LTA Headphones Project thread - Freely accessible modular headphone platforms

Discussion in 'Headphones' started by Tomislav_L, Dec 3, 2020.

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If you're interested in this project, how would you most likely make use of it?

  1. I'd like to build my headphones from scratch, by manufacturing and sourcing all parts on my own.

    5 vote(s)
    7.0%
  2. I'd like to modify the current designs and then manufacture the modified parts on my own.

    8 vote(s)
    11.3%
  3. I'd like to build my headphones using a DIY kit that only contains passive 3D printed or CNC parts.

    10 vote(s)
    14.1%
  4. I'd like to build my headphones out of a DIY kit that already contains all required parts.

    47 vote(s)
    66.2%
  5. I'd like to have headphones custom-built for me.

    28 vote(s)
    39.4%
Multiple votes are allowed.
  1. Tomislav_L

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    Hello everyone,

    Let me start off by thanking purr1n and SBAF for the opportunity to start this thread, as I have a great passion for what I'm going to present, and being able to share it directly with the community is awesome and makes it more meaningful. I hope you'll like what you'll see and make good use of it.

    I'm a headphone enthusiast, a long-time audiophile and music lover, and a hobbyist headphone designer/DIY-er from Croatia. Currently also a medical student at a university, which often limits the time I have for enjoying this hobby, but that just makes every moment I can spend doing this count even more. I'm going to present the project I've been working on for the past almost four years, and I'm going to do it in the most open and transparent way possible by giving the headphone community full access to it, including the ability to use the raw CAD files of two fully developed, completely modular headphone models, the LTA V1 and V2, for FREE. Anyone interested will be able to use the files as they are, or further modify and build upon the existing designs, in order to manufacture the parts on their own, and make their own headphones by using the project as a guide. This is something unprecedented and will allow you to skip a ton of designing, R&D, testing and prototyping, and will enable you to go straight to actually making headphones, saving a ton of headaches and money in the process.

    >>> You can download the CAD files from the links on my website.

    In addition to that, if there will be an interest for it, I will be able to provide parts in form of DIY kits, and even meticulously build headphones out of the best available accessories and materials like Carbon Fiber reinforced PA and CNC Aluminium for those interested in owning them, but unwilling to mess with the manufacturing side of things. If you're interested in something like that, let me know.

    The amount of material related to the project that I've collected in the last few years is massive, as I've tried my best to document every step of the way in great detail, so it's simply impossible to cover the entire project in-depth enough through the forum alone. For that reason, I've prepared a ~90 page PDF file with the project summarized, organized into chapters, with every part of it described in detail. This file can be used as a main source of info in combination with the LTA Headphones website, where you can also find hundreds of photos and high quality 4K renders, additional descriptions, as well as prototype assembly videos and a very detailed post-processing guide for 3D printed parts.

    >>> PDF download (9.8 MB) RE-UPLOADED 24/4/2021: https://easyupload.io/xbwue7

    There are a lot of aspects to this project on top of actually designing and building the headphones, and I've tried my best to cover all of them. You'll be able to read about state-of-the-art additive manufacturing technologies and materials used in the project, backed up by a bit of theory about designing for additive manufacturing, as well as an entire post-processing guide for 3D printed parts. In the forum thread I'll focus mostly on things directly related to the headphones themselves and cover most of it, but for additional detail and more about the project background, I highly recommend you to go through the PDF file, and let me know what you think. I will gradually be adding more and more posts to this thread, simply to make it more convenient to read and interact with. Of course, if you have any questions in any way related to the project, feel free to ask.

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    1. PROJECT SUMMARY
    Let's get right into what the project is actually all about. From the very start of it, my plan has been to come up with headphone designs that would enable me to build headphones in multiple configurations, and would basically be modular DIY platforms, with base headphone part designs that could then be combined with a variety of aftermarket or OEM dynamic drivers, ear pads or cables, and would feature plenty of sound tuning options. In addition to that, I wanted every single part of every single headphone to be easily replaceable or upgradeable, in an entirely reversible way, giving me the potential to modify and change headphone parts in the future, all in a very efficient and affordable way. As an extension to that, I wanted headphone part designs to allow me to have them produced out of a wide range of materials, from affordable to expensive ones, all while relying on state-of-the-art additive manufacturing technologies previously largely unutilized in the headphone world, potentially combined with CNC machined metal parts. Essentially, I wanted to design fully modular, entirely customizable and future-proof headphone platforms, but without ending up with some sort of a gimmick. I wanted to end up with something that would go beyond what is usually expected from DIY projects, with every aspect of the project being very well thought out, and once I'd build a headphone in a certain configuration, it would be comparable to similar headphones on the market in terms of sound quality, design, comfort and build quality, under the condition that it would cost me less to build my own headphones, than it would cost me to simply buy such similar headphones.

    I also wanted to do something nobody's ever done before and give the headphone community something that I felt its members would really like, or could make good use of, which is why a lot of the project is freely accessible to everyone, including CAD files of two headphone models, with more coming in the future.

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    A lot of my free time over the course of the last couple of years has been invested into this, at least 2000 hours of work in total, and quite a bit more if I count in all the learning of various skills involved. Even though I've revealed only 3 headphone models so far, so that amount of time might seem like a lot, I've actually designed more of them, some just as a learning experience, and some that I'm currently still working on, and that will be revealed down the line. What I've decided to reveal now isn't the peak of my work either, and there are even better projects coming up in the future. In addition, there's a lot of stuff behind the scenes that led to this, and had to be completed in order to get to a point where I was ready to start working on headphones to begin with, let alone end up with several designs. I had so much to learn from scratch in various fields, from learning how to use CAD software, learning as much as possible about various brand new additive manufacturing technologies, learning how to post-process plastic parts, and at the end of the day, learning how to actually design headphones while also employing certain novel ideas and trying to do something different. I've tested dozens of headphone parts and designs in multiple iterations during this process, and have spent a large amount of time testing and experimenting with various materials and production methods, as my goal from the start has been to end up with headphones that would not only sound good, but would look and feel good, and would be the first entirely modular headphones out there as well.

    I've tried my best to end up with something that would be interesting and useful to the headphone community, and would demonstrate the potential of the project, which is something I'd like to emphasize. Don't judge this project just for what it is right now, but for the potential it shows as well. After all, this is where the project has gotten to after only a couple of years of work, completely alone, on the side and only when I had free time, while having to learn everything from scratch, and having to do it all on a student budget. With the experience and knowledge I've gathered, working on future projects will be much easier, so there's plenty of new stuff coming.


    HOW DID THIS PROJECT COME ABOUT?


    I've been into sound and hi-fi for a very long time, and I got into headphones around 10 years ago, largely thanks to audio forums. For a long time I've been a typical audiophile discovering the hobby, trying to learn about headphones and trying out as many of them as possible. I've owned and tried a lot of headphones, pretty much full line ups of most major brands, several flagships, etc. I've written a couple of reviews back in the day, and I've always taken a lot of time to analyze the way headphones that I bought functioned, how they were designed, assembled, etc. All along the way I had an urge to modify or customize headphones and turn them into something of my own, but what usually prevented me from doing that was the fact that I intended to sell most headphones after a while in order to be able to buy new ones, and modifying them in any major way without doing irreversible damage would have been impossible. This was one of the first sparks that kind of lit the fire and led me to the idea of building my own headphones. In addition to that, since I've left home and gone to the university, I had to stop buying new headphones as often as before, I stopped testing headphones as much, and sort of settled on a couple of good setups and simply enjoyed them, until the urge to modify them started to bug me again, and that was the second spark that led me down this path of making stuff on my own. However, even only 4 or 5 years ago, designing and building something from scratch that wasn't very simple and basic, was nearly impossible for a single person. I mean, even if I had somehow managed to design something, there was no way for me to make it. The designs that I had in mind were too complex to print using affordable FDM printers, so there was just no way to prototype products without major investments, and it was just something that only actual businesses or companies could do. Also, the amount of aftermarket parts required for a project like this, such as ear pads, drivers or cables, was far more limited. However, as more and more DIY-friendly accessories became available, and as additive manufacturing technologies became more widely accessible, especially the industrial ones that I ended up relying on, the possibilities gradually started opening up, and I started investing everything I had into this project, including selling most of the audio equipment I owned at the time.


    FILLING UP A HOLE IN THE MARKET

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    One of the main goals of the LTA projects is to enable more elaborate DIY projects in the headphone community. At the current state of the headphone market, it's possible to buy headphone drivers from multiple sources, at various price and quality levels, countless custom headphone cables are available, and the choice of ear pads is almost endless, with all of these products available from OEM, as well as aftermarket manufacturers. However, when it comes to actual passive headphone components, the choices are very limited, which is not a good thing, because passive headphone components often play a part as big as the active ones when it comes to determining the sound and feel of a headphone. It's almost impossible to buy high quality headphone components that can be used as a DIY platform for all those drivers, ear pads and cables, so DIY-ers are forced to either destroy their old headphones and re-use some of their components, which almost never results in builds better than the original headphones, or they have to settle for the rare, usually quite simple and generic aftermarket components, often just reverse engineered, cheap copies of existing headphone components. At this moment, there is very little freedom available when it comes to building your own custom headphones, both in a functional, as well as an aesthetic sense. Compare the state of headphone DIY to the state of loudspeaker DIY, and it's not hard to notice the massive difference between them. The LTA Headphones project aims to completely change that and give people the opportunity to do things that were previously very difficult or even impossible.




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    2. HEADPHONE MODELS

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    Okay, let's get to the most important part now, the actual headphone models that are currently available for you to build on your own, or have them built for you. I'll present each headphone model with a general description of it, I'll write a few words about my design goals and highlights of each model, and then I'll present the actual functioning proof of concept prototypes, featuring fully finalized or close to fully finalized designs, with performance measurements and descriptions. I know it's hard to describe how something sounds, and even though I'll do my best, I'll still be using a DT770 Pro 250 as a measurement reference to at least make the measurements done on my rig give you some idea of the sound balance of these headphones. You can easily compare the DT770 graphs from my measurements to those found online in order to see that my measurement system puts out graphs pretty close to others out there. In addition to that, the drivers used in these builds are proven to be excellent and have been used in many other applications with great success, so that should give you an additional idea of the sort of sound quality level we're dealing with. Designs of the passive components don't have any features that would be detrimental to sound quality, there's plenty of customization capacity and ability to precisely manipulate the sound, and the materials the headphones are made of have excellent properties for this application. I've been extremely self-critical while working on this and made sure that every build would perform on a very competitive level in terms of cost/SQ ratio, especially when taking into account the comfort levels, materials used, build quality and attention to detail, as well as the flexibility and future-proof nature that comes from all the modular elements and customization features.
     
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  2. Tomislav_L

    Tomislav_L Facebook Friend

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    LTA V1

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    The V1 headphone is my take on the Grado-like DIY headphones. As you probably know, it's a very popular type of headphone in the DIY community, and there are a lot of drivers and ear pads on the market designed specifically for them, so they are quite fuss-free to build, which is one of the reasons I've decided to work on this model in the first place. However, I didn't want to go down the usual route of making wooden ear cups, or sticking with the standard design approach. I've decided to do something different, not just for the sake of making it different, but to offer me more possibilities with a more modern design, and to change certain things I didn't like about that style of headphone. The design is simple on the outside and I think quite elegant, with a nicely curved and angled cup that transitions into a chamfer around the grill through two soft edges. The grill sits 3 mm deep below the outer edge of the cup, and is concave in shape, so it gives a nice appearance of depth to the cup, which doesn't quite come across on the pictures. I believe it's quite a pretty headphone, but that's obviously subjective.

    There are no fasteners visible on the cups, no assembly clues, and the individual parts fit together very precisely with no gaps between them, giving the headphone a very smooth and minimalistic feel, while still leaving me some room for customization through use of various materials and finishes. Below the surface the headphone is more complex, and features a fully modular construction. It can be an on-ear headphone, or a full-sized around-ear headphone, depending on the ear pads used. When it comes to ear pads, I've kept the way of attaching them identical to other similar headphones, meaning that all ear pads on the market that fit on any Grado, or Grado-like headphone out there, fit onto the V1. That is not to say that a different attachment mechanism couldn't be easily designed if there was ever a need for it, or if I ever try to make my own ear pads, which I didn't yet. As for attaching the drivers, the standard 46 mm diamater socket on the baffle is angled, and accepts all the drivers designed for this kind of headphone that are currently on the market. The headphone has also been designed with customizable features in mind, and allows plenty of reversible ways to tune the sound.



    LTA V1 DESIGN AND FEATURE HIGHLIGHTS

    This headphone features certain unique solutions for a headphone of this type:

    Entirely modular – Every single part of the headphone is individually removable, in a completely reversible way, specifically designed to be easy to work on and to give me room for customization, which should be the whole point of a DIY headphone. For example, I can easily replace the grill for a different one, either because of sound tuning or aesthetics, or both. The cup itself has been designed with a removable outer shell, which is the part that's painted, and can obviously be used to customize the look of the headphone. The rear part of the cup can be removed from the driver baffle without removing the driver or even unplugging the cable, for easy access to the rear acoustic chamber and playing with acoustic treatment options. At the same time, because the tolerances between parts are so small (<0.05mm) and everything fits together incredibly preciely and tightly, once the parts are assembled, the cups feel rock solid. You can squeeze them, knock on them, try to flex them, and there's no weird noises, squeaks, rattles, crackling, etc. Just complete solidity. Monolithic is the term that could be used, I guess, since the whole thing feels like it's a single solid piece, and not multiple pieces assembled together.

    Angled drivers – It might sound weird put the drivers at an angle on a headphone like this, but it actually has two benefits. First, it makes the driver slightly more parallel with the angled ear, instead of the rear part of the driver being closer to the ear than the front because of how the L-cusion ear pads sit on the ears, and second, it leaves a bit more space for the earlobes when using L-cushion ear pads, so the drivers press on the ears less. Anyone who's ever tried Grado's with L-cushions has probably experienced that uncomfortable feeling of the hard driver cover squeezing their earlobe. I've designed several baffles with various driver angles/forward offsets. The ones seen here are angled at 5 deg (silver headphone) and 2.5 deg (black headphone). The angled drivers also led to an overall angled cup design, with the entire rear acoustic chamber being at an angle. This complicated the design, but on top of already mentioned advantages, it also led to certain structural benefits, making the fit between the baffle and the rear part of the cup much tighter. I can explain how and why if someone asks.

    Removable drivers – Instead of going for an approach of permanently glueing the drivers into the baffles, or press fitting them in so tightly they're almost impossible to pull out again, I've decided to go for an approach of a combination of a pretty tight fit (but not overly), combined with 6 small screws that additionally hold the driver in place. This way the driver is securely held in the baffle, but I can still easily remove it if I have to. It also allows me to adjust the driver-to-ear distance by using printed spacer rings which can be put under the driver and basically control how deep in cutout it sits. Also, it means that a single baffle is compatible with all Grado-mod drivers, since some of them are thicker than others. It just needs a specific spacer ring for each one.

    Hidden hinge yoke mechanism – The yoke is tightly integrated inside of the cup, with 12 degrees of rotation around a horizontal axis, and 360 degrees of rotation around a vertical axis, while nothing is visible on the outside of the cup, except the headband slider being connected to the cup. The issue I've always had with Grado's is that they have a very limited range of cup rotation are the horizontal axis, since the yoke itself sort of presses onto the bottom of the ear pads. That always led to the ear pads pressing the tops of my ears very hard, which is especially painful in combination with glasses. So that's something I absolutely wanted to avoid and fix. With the increased range of rotation around the horizonal axis, that issue is completely gone.

    Different headband adjustment mechanism - Lastly, the entire geometry of the headband size adjustment and the relation of that to the position of the cup has been revised compared to similar headphones. I'm using a Beyerdynamic pro headband spring steel, which is IMHO best on the market in terms of evenly distributing the force, and has an ideal amount of clamping force for what I wanted. As you can see the sliders are not straight, they're curved at a very specific radius, their initial angle relative to the headband spring is different than on Grado-like headbands, the the connection of the slider to the yoke is at a slight angle as well. I've experimented with these variables A LOT in order to ensure that the clamping force would be as even as possible at all headband adjustment positions, and to make sure there was enough horizontal cup rotation available in each position, so that the yoke is sort of in the middle position, giving the cup some wiggle room to rotate and sit on the ears comfortably. Essentially, it's making the headphone more comfortable and stable on the head, without a clamping force as strong as it's typical for a standard Grado headband, and with the forces on the scalp and the ears distributed evenly. I can wear these headphones for hours, with original L-cushion ear pads, and not feel any discomfort on my ears or my scalp. With Grado's, I used to have sore ears and a hotspot on the top of my scalp after 30 minutes. I've always loved how Grado headphones sounded, but I could never stand how uncomfortable they were, especially while wearing glasses, so I never kept them for long.



    LTA V1 DESIGN AND BUILD APPROACH

    With a fully modular construction that is easy to upgrade, the V1 is a fresh take on a classic headphone design. This completely new approach allows it to be upgraded, customized, and repaired, unlike the majority of similar headphones which are notoriously difficult to modify. In addition, the V1 design is more comfortable and performs better thanks to the state-of-the-art materials from which it is made. The core design philosophy behind the V1 model has been to make the passive parts as inert and rigid as possible. For that reason, the baffles and the cups have strategically placed radial ribs, plenty of bracing, and multiple elements designed to make the individual V1 parts fit together extremely tightly, leading to a completely monolithic assembly that is acoustically dead, thereby allowing the drivers to shine and to be the only source of sound. The rear acoustic chamber of the V1 can be treated in multiple ways too, in order to fine tune the sound. Various 3D printed inserts for the chamber with irregular patterns will be available as well to help with acoustics. A common alternative, cheaper and technically easier approach, is making cups out of relatively thin wood or plastic, which results in cups that aren’t entirely inert, instead they resonate to a certain degree, adding their own flavor to the sound. Both approaches have pro’s and con’s, it comes down to personal preference. However, because the V1 is designed for an extremely clean sound, the approach of achieving extreme rigidity through clever design and advanced materials has been chosen. Using wood would introduce massive design limitations and would make the creation of a modular headphone virtually impossible, while achieving high rigidity the traditional way, by using very heavy metal cups, would lead to poor comfort as well. Utilizing additive manufacturing and state-of-the-art materials, far superior to those used on any similar headphone, has helped a lot in the development process, and made it possible to hit the performance goals, while keeping the weight of the headphone low and offering better fit and comfort compared to similar headphones.

    These prototypes had all parts produced with HP Multi-Jet Fusion machines, out of a PA12 plastic material. This additive manufacturing technology is highlighted by incredible dimensional accuracy, virtually no design rules, and the ability to produce very complex parts, very quickly, ready for use straight out of the machine. It's a very strong, durable, wear-resistant and chemically-resistant type of plastic meant specifically for highly demanding engineering purposes. Also, it has great elongation at break properties, meaning that it's really impact resistant. Think of it as opposite of brittle. It's not necessarily flexible, because it's really hard to flex even the thin parts, but you have to really bend a part way beyond it's original shape to break it. It also has great vibration-damping properties.

    Some of the parts are raw, without any post-processing, and have a very fine and pleasant texture on the surface, while others have been post-processed by me, all done by hand. I had to experiment with post-processing quite a lot, as when I started doing this, there was absolutely no sources on how to post-process SLS or MJF printed parts. It took a lot of time and testing to develop a method that allows me to achieve a perfect finish. You can find more information on this topic in my detailed post-processing guide.

    The V1 headphones that I'll build and provide parts for in form of DIY kits will be produced out of Carbon Fiber reinforced PA, using SLS technology. A material very similar to the one used on the prototypes, but additionally reinforced with CF, and up to 8x more rigid and stronger than ABS plastic used to build most headphones on the market. It truly is the most advanced and simply the best plastic material that can possibly be used to build these parts in their current form. I might even experiment with CNC machining aluminium parts in the future, which would make the headphones look identical to the ones on the renders.



    LTA V1 CUSTOMIZATION LIST

    On top of being able to use the V1 model as is, in it’s standard configuration, it's possible to reversibly modify the headphones through several customization options:
    • Replaceable 46 mm diameter drivers with multiple high-quality options available on the market, all from well known and respected manufacturers, specifically developed for this type of headphone. With this simple and reversible modding capability, it’s like having multiple headphones in one.

    • Adapters for drivers under 46 mm which will fit into the original driver sockets just like the 46 mm drivers do, meaning the process will be entirely reversible and risk-free.

    • Driver spacers allowing for fine tuning of driver-to-ear distance. How far from the ears the drivers sit has a subtle effect on the sound, making the sound slightly more aggressive by shortening that distance, so it’s useful to have a simple and reversible method of finding a personal favorite configuration.

    • Removable ear pads with a large selection of OEM and aftermarket options available for sound and fit/comfort customization. The default ear pads attached to the V1 are original L-cushions. Depending on the drivers used, the optimal ear pad can change, which is not a problem, since swapping them is extremely easy.

    • Acoustic treatment materials for the rear acoustic chamber provided with the headphones, with several damping and/or sound-absorbing materials that can be used to line the internal walls and/or fill the space of the chamber. They can also be used to reduce or increase the volume of the chamber. All of the effects of these procedures are reversible, subtle, but noticeable, and give owners options for their favorite configuration.

    • Acoustic mesh filters for the rear grills will be provided, enabling additional sound customization by damping the ear cup grill to a specific degree based on how transparent or dense the acoustic mesh is. Several meshes with a useful range of acoustic impedance specs will be provided with each V1 headphone.

    • Replaceable grills with various designs will be available in the future for affordable and reversible aesthetic and functional modifications. Owners will even be able to create their own designs.

    • Removable outer ear cup shells enable simple future aesthetic personalization without having to replace the rest of the cup.


    LTA V1 v.1.0. FINAL PROTOTYPES

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    After many iterations of V1 parts and a lot of experimenting with design variables through multiple prototyping cycles, I've arrived at what I'd consider a finalized version of the headphone. Not necessarily the last one, as I'm always finding ways to improve the design, but it's finalized in the sense that it's well polished down to the last detail in terms of the assembly process, the fit and finish of the parts, the way the build feels, and in the way it performs. It's also the version that is available in form of DIY kits and as a pre-built headphone, while the 3D CAD files are already available for downloading and non-commercial use by anyone.

    I'll show two headphones here, one finished in metallic silver and the other in metallic black. They're 95% identical in terms of part designs, the only major difference being the fact that the silver version features drivers angled at 5 degrees, while the black version has them angled at 2.5 degrees. In addition to that, the black version has a dual-layer grill design, that secures the acoustic filters in place better than before, and it features a different type of acoustic treatment in the cup itself. All of these variables are minor, and both versions of the headphone perform very similarly, but with some differences nonetheless.

    First about the similaries between the two builds,
    and I'll describe them as a single headphone, as both of them are the V1 model after all. They both feature the same driver, the Elleven Acoustica P1. Why? Of all the Grado-mod aftermarket drivers I've tried, I like this one the most, and it's objectively simply an amazing driver, possibly one of the best dynamic headphone drivers out there, with a great ability to function equally well in various types of headphones, not just Grado like builds, which is a huge added bonus. When it comes to ear pads, I like the sound of this driver best when combined with original L-cushions, and that's how they were measured.




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    LTA V1 v.1.0. SILVER – PERFORMANCE

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    It's really hard to describe the sound of this headphone in any other way than saying it sounds very balanced, from top to bottom. I guess neutral would be the word that could be used as well.

    The V1 in this configuration has a very focused, tight, fast, highly detailed and punchy sound, but with wonderfully sweet and full mids, one the best I've ever heard from a dynamic headphone. Not just in terms of how full they are, but in terms of how natural and transparent they are. The "shouty" character typical for similar headphones caused by the ~2kHz peak is almost non-existent too, especially on the black version of the headphone with its acoustic treatment. Mids are without a doubt the highlight of this model in terms of sound, and for that reason it's simply brilliant when it comes to vocal and instrumental music. In addition to that, the overall sound resolution is very, very high, absolutely comparable with any <$1000 dynamic headphone, and some above that too. I've used the T1's for many years as a reference headphone, but I'd absolutely never pick them over the V1's for any music that focuses on real instruments or voices.

    The low end is very quick, punchy, clean and tight, with a great "texture" and a better extension than is typically the case with this type of headphone. It's still not an LCD4, but it's definitely not a typical Grado either, with their massive mid-upper bass peak and a sudden roll off at the bottom. This is a bass response that's very even, without an obvious peak or a "one tone" quality, and with an extension that matches most full-sized open-back dynamic headphones with ease, only starting to roll below 1kHz SPL level at about 50-60 Hz. Even at 40 Hz, there's still plenty of "rumble" present when needed.

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    Higher frequencies are slightly accentuated, although not to the extent typical for a headphone of this type, and nowhere near the point of making the headphone bright. Instead, they provide a great sense of clarity and air in the sound, without being aggressive. This can be further fine tuned with the use of various acoustic foams and fabrics in front of the driver. When leaving the driver uncovered, or with just a transparent dust filter, there's a lot of detail throughout the frequency range. I'm not gonna use the "I can hear things I haven't heard before" cliche, because I've heard plenty of high-end headphones, but this is one of those that makes you notice micro-details and fine nuances in music that most headphones mask or don't make nearly as apparent, and I can tell that with confidence becauase I've been using a certain selection of reference tracks for years, and know exactly how they sound with various headphones. At the same time, it's not a headphone that pushes details forward and tries to be overly analytical, and it's not as aggressive or rough in its presentation as the original Grado's are. It makes music involving and fun to listen to, but in a more refined way. It's more of a velvety smooth saxophone than a loud and distorted electric guitar, and that's all thanks to that sweet mid-range and a very smooth, quick and well controlled sound. This might actually be the most impressive thing about it, because sometimes headphones with this level of detail, clarity and speed tend to be overly analytical, aggressive and cold, but the V1 manages to avoid that very successfully.

    As with all high quality headphones, a high quality source is a must in order to fully explore what it's capable of, and poorly recorded music will have all its flaws exposed, and it's definitely one of those headphones that makes me avoid certain recordings. On the other hand, they're actually very easy to power, and even just plugging them into a smartphone makes them sound great, but with a limited headroom in terms of volume level.

    The sound stage with L-cushions is medium in size, but offers good imaging and great separation. Using the P1 drivers in combination with the G-cushion ear pads results in a slightly higher level of comfort and a slightly more distant and laid back sound, with a bigger sound stage and a greater sense of openness in the sound. That being said, I'm not a big fan of that combination, and don't think the benefit of a bigger sound stage is worth sacrificing the rest of the sound for. There are drivers on the market specifically designed for use with the bigger ear pads, and these aren't one of them, so I personally prefer the L-cushions.

    When it comes to specifics of the silver V1 build, other than the obvious visuals, this build sort of represents the most basic configuration possible. In terms of acoustic treatment, it only features a 2mm thick EVA foam padding on the walls of the acoustic chamber, and a perfectly transparent stainless steel mesh under the grill, which has no effect on the sound at all. Essentially, it's as raw as the V1 can get with these drivers.

    [​IMG]

    As can be seen, the silver LTA V1 prototype has a very smooth frequency response without major peaks or dips, going through frequency sweeps while listening to them confirms that. The area from 50 to 1500 Hz is particularly flat, explaining the extremely accurate vocal and instrument reproduction, as well as the incredibly tight, punchy and clean low end, something that this headphone excels at.

    Note that I'm using the DT770's only as a reference to show how my measurement rig works. I'm not using them as a performance benchmark. With all due respect to the DT770's, and I love these headphones and think I'll always have a pair around for the rest of my life, every aspect of sound is just on a different level with the V1's, as it should be, considering the drivers used in this build alone cost almost twice as much as the DT770's.

    From personal experience, speaking subjectively, I would put the V1's sound (in this configuration at least) above the level of mid-range headphones, for example the HD600, and at the level of the Beyerdynamic T1 (one my favorite dynamic headphones ever) in virtually every aspect of performance other than the size of the soundstage and the bass extension below 50 Hz. I'd even rank them above the T1 in terms of mids, and how they reproduce vocal and instrumental music. The fact that it can be built for approximately 2/3 of the cost with highest quality materials, makes it even more impressive. Keep in mind that this headphone still doesn't make use of the more expensive reinforced polyamides and CNC machined aluminium in it's production. Both of those materials are going to drastically increase the overall rigidity of the ear cup assemblies, resulting in an even better sound. In addition to that, various additional acoustic treatments can be utilized to fine tune the sound to ones liking.
     
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  3. Tomislav_L

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    LTA V1 v.1.0. BLACK - PERFORMANCE

    [​IMG]

    I've built another prototype with slightly updated parts, with very minor design changes, just an added second grill on the rear opening of the ear cup that helps keep the filters or metal mesh sandwiched in place under the main, outer grill. It adds nothing to the transparency of the overall opening, as the inner grill design is perfectly aligned with the outer grill.

    More importantly, this configuration features more advanced acoustic treatment than the previously shown one. The internal walls of the rear cup chamber are lined with a layer of Dynamat, and then a layer of 3 mm thick acoustic felt on top of it, with the possible addition of speaker-box damping material, like "Angel hair". These changes make the cup more inert, and reduce the reflections off of the internal walls. In addition to that, the parts feature something I've been experimenting with for a while, and that is using liquid glass, or a special type of epoxy resin, to fill in the cutouts in the components. The reason for doing this is the fact that this resin, once cured, is extremely rigid and inert, far more than any plastic material I could use to make the components out of, while being only slightly heavier than plastic at the same time. This means that printing components with cutouts, and then filling them in with epoxy resin, leads to more rigid and inert components than they would have been if they were to be printed without cutouts to begin with. The amount of resin used leads to different effects, so in a way, this method can be used to control the resonant properties of plastic parts. The improvements in rigidity will be even more noticeable when I make the raw components themselves out of superior materials such as the Carbon Fiber reinforced Polyamide, which might put them on this level of performance even without filling them with epoxy resin. Another change compared to the previously shown configuration is the mesh used under the grill, which is not a stainless steel mesh, but a Saati polyester acoustic filter, slightly more transparent than the stainless steel mesh.

    [​IMG]

    In terms of performance, this configuration is a noticeable improvement over the previous one subjectively speaking, not by a large margin, as it's mostly an identical headphone, but still an improvement. The acoustic treatment of the rear chamber has led to a slightly more even frequency response, with a 2 kHz peak slightly reduced, and an overall smoother sound, particularly in the high frequencies. On the other hand, the additional rigidity and mass of the components due to the epoxy resin filling has led to a slightly tighter, quicker and punchier bass response.

    Below, the frequency response can be seen in a direct comparison to the DT770, without any smoothing applied, 1/24 oct setting in ARTA, giving the most detailed graphs possible. As can be seen, the curve is smoother and more even than previously, with slightly increased SPL in the low end, and flatter upper mid range. CSD Waterfall plot can too. The extreme proximity of the driver to the wooden panel of the measurement rig in this case cause a lot of tiny peaks in the highs which aren't audible when actually listening to the headphones. When using some felt padding on the measurement rig, that's gone, but it also ruins the seal of the ear pad and makes the low end unrealistically rolled off, so these are the most accurate and "raw" measurements I could have made.

    [​IMG]

    Below, I've added a collection of three measurements with an identical headphone, without being removed from the measurement rig. The only difference is the adjustment of the headband size, leading to slightly tighter and stronger clamping force with each reduction in size. Green line is the lightest clamping force, red the strongest. This is to show how the clamping force of the headband affects the sound of a headphone, and how important it is to adjust the size of the headband when wearing a headphone, enabling an optimal seal between the ear pad and the ear. This is also obviously an important factor when attempting to couple an ear pad with a flat piece of wood in order to achieve a proper measurement. In addition, the headband spring I'm using currently is already 3 years old, and has been stretched out significantly, meaning that a brand new spring would lead to an even higher clamping force, and an even better seal, which is crucial with these headphones.

    [​IMG]

    In any case, the measurements shown here are the worst-case-scenario ones, because of all the materials that I can potentialy use to make the parts out of, the most affordable ones have been used to produce these parts. On top of that, I can still explore additional acoustic treatment options, the ear pads I have are already slightly worn-out, and the old headband spring is not clamping as hard as it could. Despite that, the headphones perform very well and subjectively sound excellent, definitely competitive with upper-tier Grado's, while costing less to build.

    [​IMG]

    ULTIMATE VERSION OF THE LTA V1

    The final goal, as with other models I've designed, is to build them in a top configuration, featuring the most advanced Carbon Fiber reinforced Polyamide on functional components, in a combination with CNC machined Aluminium structural and mechanical parts in the future.

    Several renderings of such headphones can be seen in the render gallery on my website, in various combinations of materials and finishes. These hypothetical headphones have all internal parts built out of Carbon Fiber reinforced Polyamide, while the mechanical and structural parts are CNC machined out of Aluminium. Cup shells and headband pieces can be brushed, polished or anodized to any color, with a matching apparearance. In case of a brushed finish on these parts, the grills and the headband sliders would be anodized to a black matte finish, with a laser engraved LTA logo on the grill, and a stainless steel mesh behind the grill. It would be a play between two contrasting Aluminium finishes, combined with the reflective nature of the stainless steel mesh, and I believe a headphone like that would look excellent in person. It's my personal favorite aesthetic configuration. Needless to say, the build quality, solidity and durability of such a configuration would be excellent, while the overall rigidity of the headphone would lead to the best possible sound quality that this design can offer, regardless of the driver, ear pad and acoustic treatment combination.



    FUTURE PLANS FOR THE LTA V1

    • I plan to further develop this model and offer more options over time. For example, two baffle designs have been developed already, one with the driver at a 2.5 degree angle, and the other at a 5 degree angle.
    • Inserts for the driver socket will be available for drivers with a diameter below 46 mm, which will enable one to fit a wider range of drivers to these headphones. Adapter rings for fine tuning the driver-to-ear distance have already been developed as well, and they'll also come in handy when fitting 46 mm drivers that have various thicknesses. The Elleven Acoustica drivers are 8 mm thick, but there are some out there at 7 or 9 mm.
    • Various grill designs will become available over time, both for aesthetic and functional purposes, and hopefully CNC machined out of aluminium as well. Pre-painted cup shells will also become available, as well as those CNC machined out of aluminium. In general, my goal, if there will be an interest for it, is to produce parts out of CNC machine aluminium.
    • The LTA V1 model will be available in form of DIY kits, as well as in several versions of fully built headphones. Spare parts and upgrade parts will be available as well, such as various types of 3D printed inserts for the rear acoustic chamber, which will allow one to tune the chamber diameter, volume, shape and the reflective properties of the walls, as various patterns will cover the 3D printer inserts.
    • With more and more drivers coming onto the market, it's possible to imagine that in the future, owners will be able to vastly improve the performance of their headphone in a very affordable manner, and always entirely reverisIbly.
     
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  4. Tomislav_L

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    LTA V2

    [​IMG]

    The LTA V2 is a headphone that's been designed and developed as a traditional open-back headphone, and an alternative to the more complex V3 model, offering a different sound character and a more elegant, minimalistic appearance, while maintaining the same level of quality, attention to detail, durability and toughness. Just like the V3, the V2 heavily relies on the most advanced additive manufacturing technologies to an extent previously unseen in the headphone industry and can feature the same cutting-edge materials in the construction, such as Carbon Fiber and Graphite reinforced polyamides, Multi-Jet Fusion PA12 and CNC machined aluminium. In addition to that, it's been designed as a fully modular headphone, not only acting as a high quality standalone product, but also as a fully modular DIY platform, enabling full freedom to build, assemble, disassemble, test, experiment and customize the headphone in aesthetic, as well as functional aspects. The idea is to offer as much flexibility and freedom to headphone builders as possible, similar to the flexibility custom PC builders or DIY speaker builders have had for years, but at the same time without sacrificing any of the things necessary for ending up with a high-quality headphone that can be very competitive against similarly priced offerings on the market. In addition, the ability to easily replace and upgrade every single component of the headphone using basic tools will prolong the life of the headphone.

    The basic geometry, the headband, the hinges, frames and ear pad attachment rings are shared between the V2 and the future V3 model, which means they're virtually identical in terms of feel, fit and wearing comfort. What is different though are the ear cups themselves, which are designed in a more traditional open-back headphone fashion on the V2, meaning that the driver sits between two chambers, separated by a baffle that contains tuning ports or vents, with the rear chamber being opened to the back and covered with a grill. The rear chamber contains both the driver and the tuning ports, which is the main difference between the V2 and the V3, with the V3 having the driver chamber completely separated from the tuning ports and the rest of the headphone. Each concept has pros and cons that come down to personal sound preferences. Internally, the headphone has been designed to accept a wide range of drivers, featuring replaceable driver holder components, removable ear pad rings, as well as unique filter frame components, enabling simple and quick customization of the headphone's sound character depending on one's personal taste, as well as adapting it for use with various driver and ear pad combinations. Another unique aspect of this headphone, further increasing the DIY potential, are the three variations of the basic baffle design featuring different enclosed ear pad volume shapes and driver positions that will be available, each carrying with it a specific acoustic character. On top it, the large and spacious design of the ear cups enables even more modifying freedom in the future, because the V2's baffle can easily be completely redesigned not only for use with various types of dynamic drivers, but also for use with orthodynamic, planar magnetic or even electrostatic drivers, as there is more than enough room for them in the cups, and with all the tuning possibilites necessary, easily available. In addition, the headphone can be modified into a semi-open or even a fully closed version, depending on the type of ear cup grill or cover that it uses, as well as the type of headphone driver fitted to it. All of these are plans for the future and further evolution of this headphone model, some of which are already being worked on.



    LTA V2 DESIGN AND BUILD APPROACH


    The design of the passive components is one of the V2’s crucial aspects and is what gives this platform its main advantages. The design of the baffle and the driver holders is at the center of this. It’s a system of four separate, extremely complex components: the two-part driver holder, the filter frame, and the main baffle body. Every detail on each of those components is intentional, and done with the purpose of not only making the headphone entirely modular, but also creating the most rigid, inert, and acoustically neutral baffle possible. The baffle overall is irregular and asymmetrical because the drivers are at an angle. This combines with strategically placed and designed ribs, which are radially spread around the driver itself in order to provide the highest rigidity exactly where it’s required. These ribs continuously flow from the baffle onto the driver holders, with an extremely tight fit between them. The whole "sandwich" of ear cup components is held together by more than 20 fasteners, so the assembly is rock solid. Combined with the stiffest and strongest material in the additive manufacturing world, the V2 baffle ends up being one of the most rigid in the headphone industry, allowing any dynamic driver to be used with it to its full potential. In addition to rigidity, the very irregular shapes also help eliminate resonance modes inside of the ear cup. On top of that, acoustically absorbent material line the inside walls of the cup, while special acoustic foam fills the entirety of the internal cup volume. All of this ensures a very clean acoustic environment, resulting in a very even and smooth sound, illustrated by the lack of sudden peaks or dips in the frequency response and an extremely clean CSD waterfall plot. Starting from this solid foundation, it’s easy to use the modular aspects of the V2 to tailor the sound to one’s own liking, regardless of the drivers or ear pads used.



    LTA V2 CUSTOMIZATION OPTIONS

    In addition to the standard configuration, V2 can be modified to anyone's liking through several customization options:

    • Replaceable 40 to 50 mm diameter driver units with multiple options available on the market at a wide price and quality range, from various OEM and aftermarket manufacturers. The V2 headphones can be fitted with pretty much all of them, in an entirely reversible and simple way, unlike any other headphone on the market. This gives the V2 headphone platform a lot of flexibility and potential, and gives the owners an opportunity to build unique headphones in the future, without having to replace an entire unit.

    • Unique and removable driver holder components enable quick driver swaps, with various driver-to-ear distances and several acoustic filters available. Driver holders are an excellent solution for swapping the drivers, because they’re the only components that have to be changed, the rest of the headphone can remain the same, so swapping drivers is as affordable as possible.

    • Unique and removable filter frame components enable owners to fine tune the size and shape of the enclosed ear pad volume, which is another unique LTA features which makes sound tuning extremely flexible. The exact methods of use, and the effects of various filter frames on the sound, will be explained in the example section below.

    • Several types of acoustic mesh filters can attach over the tuning ports on the filter frames, allowing owners to find the exact configuration they like. Once a couple of configurations are determined, owners will be able to order or build custom filter frames with specific acoustic mesh filters fitted to them. This will enable them to quickly swap filter frames and reversibly switch between their favorite sound signatures. It’s like having multiple headphones in one.

    • Damping the rear driver ports is another quick, simple, affordable, and fully reversible way of manipulating the sound signature. Several damping acoustic mesh pads will be provided with the headphones. Their effects are described in the use case example section.

    • Removable ear pad frame components designed to fit any ~100mm diameter ear pad (industry standard) on the market from manufacturers like Beyerdynamic, Dekoni, Brainwavz, etc. Whether you decide to stick with the excellent provided ear pads or upgrade them, you will have plenty of choices. Each ear pad gives the headphone a unique feel, fit, and effect on the sound, giving owners an opportunity to find exactly what they like.

    • Ability to tune the acoustic properties of the rear chamber allows for additional sound tuning options, by making it possible to customize the transparency of the grill, the volume or size of the chamber, the reflective properties of the chamber walls, as well an ability to fill the volume of the chamber with various acoustic materials, such as polyfill.
    • Acoustic mesh filters for the rear grills will be provided, enabling additional sound customization, with several acoustic impedance spec options.

    • Removable hinge yokes and ear cup frames enable simple future aesthetic personalization.

    • Parts are designed so that they can be produced using various manufacturing methods, including Carbon Fiber reinforced polyamide and CNC machined metal parts.

    • The baffle will be available in several versions with drivers placed at 5, 7.5 and 10 degree angles, with fully removable and replaceable filter frames and driver holders for each specific version. They're already at the end of development.
    • Possibility to develop baffles for other types of drivers because of the size and shape of the V2 ear cup, giving this headphone model the potential to feature orthodynamic, planar magnetic, or perhaps even an electrostatic drivers in the future, while keeping the basic structure of the headphone unchanged.
    All of these features leave pretty much an endless ability for tuning the sound and achieving desired results, and because the plastic components themselves are so incredibly rigid and acoustically neutral, it's not very difficult to find a proper balance with any combination of drivers and ear pads.



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    LTA V2 v.1.0 PROTOTYPE - Elleven Acoustica P1 drivers

    [​IMG]

    The headphone featured here is the older v.1.0 prototype featuring the 46mm driver baffle design. This prototype is fully manufactured out of a PA12 polyamide, produced using HP Multi-Jet Fusion technology, so the Carbon Fiber and Graphite reinforced polyamides weren't used in order to reduce prototyping costs. These prototype headphones feature an Elleven Acoustica P1 driver, Beyerdynamic T1 gen. 2 ear pads and SAATI Acoustex acoustic mesh filters. Despite the fact that they're built out a material less strong and rigid than the Carbon Fiber and Graphite reinforced polyamides, or the CNC machined aluminium parts that can be used, the headphones are on a very high level in terms of mechanical properties. Assembled headphones feel rock solid, with no flexing, creaking or squeaking, but very lightweight at the same, with a high level of rigidity and strength, a combination which is hard to appreciate without experiencing it in person. It fully highlights all the advantages that the superior Polyamide has over the most commonly used ABS plastic.

    [​IMG]

    PERFORMANCE – P1 drivers

    In terms of performance, nothing surprised me, as I've gotten used to the versatility and quality of the P1 driver, and the frequency response I had predicted during the design turned out pretty much exactly as planned. In order to fully utilize the performance of the driver and achieve the planned sound balance, certain crucial design goals have been met during development, such as using the correct sizes and shapes of tuning ports on the baffle, finding the right driver-to-ear distance, as well as modelling the proper shape and size of the enclosed ear pad volume. These goals have been fairly easy to achieve by applying the experience and knowledge gained while working on the V3 model. As mentioned previously, I've even designed several types of baffles for this headphone model, with the driver placed at different angles and forward offsets. The 7.5 degree and the 5 degree baffle are very similar due to featuring the same driver and acoustic mesh, as well as the same total baffle port area and the same enclosed ear pad volume, so the only variable between the two designs is the position of the driver relative to the ear. Simply put, the 5 degree version is a tiny bit more neutral and less sensitive to positioning on the head, but has a slightly smaller soundstage and a slightly less pronounced frontal projection than the 7.5 degree version. The difference is very subtle.

    [​IMG]

    This prototype has no special acoustic treatments applied to it, the rear chamber is not lined with felt or foam, but can be, the rear grill is fully opened apart from a very transparent mesh covering it, and there are no filters in front of the drivers, but despite that the headphone performs very well, very close to the intended goal. The sound of the headphone is very smooth, clear and transparent, with an almost perfectly flat frequency response from 100 to 3000 Hz, with the smooth bass peak at around 80 Hz, with excellent bass control without any bleeding into the mid frequencies, and only a slight SPL rise between 6 and 10 kHz. It's not a perfectly neutral headphone at this stage of tuning, it's perhaps a touch brighter than I'd wish, not so much because it sounds too bright (and it's less bright than many fully-opened headphones out there), but because of how sensitive it can be to bad recordings. However, while simply listening to high quality recordings instead of analyzing the sound, it's evident that the headphone is capable of extracting an incredible amount of information and detail out of them, it has a very quick, tight and punchy low end, and some of the best mids I've heard from a dynamic headphone, which makes this headphone particularly great with instrumental and vocal music. Definitely above most dynamic headphones that can be purchased for the cost of putting this prototype together, well, if I exclude the overall cost of development, that is. In addition, it's very "musical" and fun to listen to, and the amount of drama and emotion this headphone can bring out of the music is amazing, thanks to the incredible speed and dynamics combined with forward and full mids. In that way, it's the complete opposite of certain high-end headphones on the market that are technically great, but can still sometimes be overly cold and dull to listen to.

    [​IMG]

    In addition, the sound balance of the it can be easily controlled and modified by simply using different acoustic mesh on the filter frame ports, as shown on the graphs below. Using a slightly less transparent mesh on only two ports out of twelve, results in a linear and smooth boost to the low end by approximately 2 dB, as well as an equal reduction of the 1-3 kHz area. Using that mesh on four out of twelve ports further amplifies the effect. The results are always very predictable, and obviously a modification of the sound in the opposite direction is also possible, by using more transparent acoustic mesh. If we take into consideration that there are 12 tuning ports on the baffle, and various types of acoustic mesh filters available, with each port potentially covered with a different type of mesh, it quickly becomes clear that the tuning capability is immense, with an ability to fine tune the frequency response with a precision better than +/- 1 dB. In addition to that, partially blocking the rear grill with felt, acoustic fabric or acoustic mesh, gradually accentuates the 1-5 kHz region and tightens the bass, which adds an additional dimension of tuning. The driver-to-ear distance can also easily be adjusted by using different driver holder components and driver spacer rings, currently available for three positions, 0mm, +1.5mm and +3mm. Moving the driver away from the ear makes the sound less aggressive and forward, with slightly smoother upper mids and highs, and a slightly softer bass impact. Differences between the steps are subtle, but easily noticeable.
     
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  5. Tomislav_L

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    ALTERNATIVE AND IMPROVED BAFFLE DESIGN

    I've designed an alternative and improved baffle that can accept drivers other than the 46 mm ones. This baffle design can accept a wide range of aftermarket drivers up to 50 mm in diameter, regardless of the design and shape of the driver, enabling builds with an even wider range of possibilities, with any of the hundreds of aftermarket drivers available, or even OEM drivers available from various headphone brands. The driver attachment system is slightly different on the alternative baffle design, with a separate two-piece driver holder design. The driver is attached to the front piece, which is then press fitted into the baffle, and then the rear piece is pressed onto the back of the driver and additionally secured using six fasteners and brass threaded inserts, making sure that the whole assembly is extremely strong and rigid. The driver holders can be printed in various lengths, enabling driver-to-ear distance adjustments. In addition, in case the driver requires a proprietary attachment system that some OEM drivers use, the driver holders can easily be designed according to those demands and enable a perfect fit for virtually any driver out there. Because the driver holders are completely separated from the rest of the ear cup, it's possible to remove drivers together with their driver holders by removing the six screws, and then simply attach a different driver + driver holder combination in the place of the old one. The best thing about this system is that the driver holders are relatively cheap to print, certainly far cheaper than most of the aftermarket drivers.


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    LTA V2 v.1.0 PROTOTYPE – Peerless drivers

    [​IMG]
    As promised, many alternative baffle designs will be available for the V2 headphone platform over the time. The current latest design can be seen on the prototype below, and has been developed with an intention to house drivers that range from 40 to 50 mm in diameter and can be considered the ultimate version of the V2 baffle. It's also the version that will be made public and available for everyone to use its design, as it's the most flexible version of the ones that I've designed. In this case, the excellent Peerless HPD-50N25PR00-32 set of drivers has been used to build a prototype. The Elleven Acoustica P1 drivers mentioned above can also be fitted using modified driver holders. The Peerless drivers are well known and respected, and used in several great headphones on the market with great results.

    This V2 model is no exception, offering a higher level of rigidity and a more advanced design than any comparable headphone on the market that uses these drivers, it manages to extract all the performance that these excellent drivers have to offer. At the same time, this is proof of how well developed the LTA V2 modular platform is, and how easy it makes to switch between two sets of entirely different drivers, and end up with excellent results in both cases.

    [​IMG]

    The alternative baffle design differs to the above mentioned standard design only in the way the drivers are attached to it. Physically and functionally, both designs are identical. The shapes and sizes of both baffles are actually identical. The shapes and sizes of enclosed ear pad volumes, the sizes of filter frame tuning ports, the ear pads, and the rest of the cup assemblies are identical between the two builds. Functionally speaking, the only variables that are different are the drivers and the acoustic mesh filters used on the filter frames. Because the Peerless driver is slightly bass-heavier than the Elleven Acoustica P1 driver, the total amount of venting or leakage out of the enclosed ear pad volume it requires is slightly higher. For that reason, 4 out of 12 ports on the filter frames have been covered with a more transparent acoustic mesh than on the P1 build, which has led to an ideal frequency response balance that can be seen below.

    Furthermore, this alternative baffle makes it incredibly easy to replace drivers, as the entire driver sub-assembly is removed from the baffle as a single piece, only requiring 6 fasteners to be removed, a new driver sub-assembly can then be attached, and the 6 fasteners put back into place to secure the driver.




    PEERLESS DRIVERS ARE A GREAT CHOICE

    There are multiple headphones on the market using these drivers for a very good reason, as they've proven to be excellent in a wide range of headphone designs. It's one of the reasons why I've decided to use them as well. These drivers are essentially the reasonable and safe choice, and objectively a great performer in many well regarded headphones, such as models from Aurorus, Kendricks, Hyland, etc.

    [​IMG]

    When I started the project of designing modular headphones in 2016, this is the sort of driver I had in my mind, something that objectively performs on a very high level and can compete with upper tier dynamic headphones, but has the flexibility to work well in various types of headphones, with a wide range of sound signatures, and in this particular case, are the best drivers with the V2 that I've tried so far. There are more drivers like it on the market, they're just "under the radar" at the moment, and require a properly designed modular platform that allows people to experiment with them and discover what they're capable of. Such a platform did not exist until now, and people were forced to disassemble and modify old headphones designed specifically to work with their OEM drivers, take those original drivers out, and then somehow fit the aftermarket drivers into them, with no optimal ways to tune such headphones. Not the best way to do things, and inevitably leads to mediocre results at best. With the modular platform as well designed as the V2, you'll have the ability to test and try various drivers and discover all kinds of excellent examples on the market. In that sense, think of the V2 as a high quality body shell and chassis for a track car, which will work well with various suspension or drivetrain parts attached to it.

    For now though, this is the driver that I will be installing into the V2's by default and that I recommend as an excellent sounding option that also happens to be a ridiculously good value for money. With time, more driver combinations will be discovered and introduced. That's the beauty of a modular headphone. It doesn't matter how it's built today. If in two years from now some new company releases some spectacular new driver, it won't be a problem at all to pair it with the V2 platform and upgrade the headphone to a whole new level of performance, something other headphones simply can't do.



    PERFORMANCE – Peerless drivers

    As already mentioned, the Peerless drivers are excellent, and it shows in the performance of this prototype headphone. In comparison to the P1 build, the Peerless build has a slightly flatter frequency response, with a more even performance from top to bottom, and is easier to manipulate in terms of sound signature. The bass extension is better due to higher excursion and larger diameter drivers, and this gives the headphone a deeper foundation than with the P1 drivers. It can still be tuned to be superbly tight and well controlled, without any bleeding into the mids, but the P1's have a slightly more defined and quicker impact. It's a matter of preference, but I believe the Peerless build bass response is better suited for a wider range of music genres.

    The mids are entirely flat, without the upper-mid dip that the P1 build has. This gives the Peerless build a more even and smooth overall feel, but at the same time, these drivers don't quite match the level of resolution that the P1 drivers have, for those who prioritize resolution over everything else, the P1 build is still slightly superior. That being said, the Peerless build is still absolutely competitive with any opened dyamic headphone up to $1000 in that regard, and some above.

    What the Peerless build does really well is avoid any harshness while not lacking detail, because the highs are quick and detailed enough to be worthy of an upper-tier dynamic headphone, but without the sort of sharpness that can sometimes be heard from headphones such as the HD800's or T1's. The P1 build can be a tiny bit bright with some badly recorded music, and can exaggerate faults in bad recordings, whereas the Peerless build is less picky in that sense, and isn't as sensitive to the quality of recordings. For that reason, it's a headphone that is better suited for a wider range of music genres and recording quality levels, but at the same time, it still extracts a level of detail out of the music that the average mid to upper-mid range headphones simply don't, and still leaves an impression of a very resolving headphone, just not to the extreme extent of the P1 driver build. I guess a good way to describe the sound would be to say it sounds fluid and is easy to listen to for long periods of time, whereas the P1 build can be tiring with it's microscopic level of detail. The soundstage is also slightly larger with the Peerless drivers, there's a more intense sense of space and air in the sound, and this also makes them excellent for gaming and movies.

    [​IMG]

    In either case, both builds have their pro's and con's, and while the P1 build ultimately does have a slightly higher level of resolution, it's in my honest opinion an irrelevant difference at this level anyway, because both builds are more than resolving enough, and the Peerless build is still an absolutely amazing sounding headphone, with excellent value considering the cost of putting it together. Without any doubt in my mind, there is no dynamic open-back headphone on the market that performs this well at a price similar to the cost of putting this headphone together. It's also the reason why these drivers are my current favorite to put into this build, and why I consider it the default driver for this headphone model at this time.

    On top of that, the platform is entirely modular and future-proof, which makes it an even better value for money in the long run. Nothing prevents one from tuning the sound to their liking, or even installing entirely different drivers into the V2 build while keeping the vast majority of the headphone unchanged.

    [​IMG]
     
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  6. Tomislav_L

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    LTA V2 CUSTOMIZATION EXAMPLES

    In order to more easily understand the benefits of modularity, it’s useful to look at a real world example of customizing the V2 headphone with the Peerless drivers.

    • FILTER FRAME REPLACEMENT

    For example, changing filter frames is an easy way to manipulate the general sound balance of the V2 headphone. That is because the overall tilt of the frequency response, especially in the range up to ~2000 Hz, mainly depends on the total acoustic impedance of the tuning ports on the filter frames/baffles, or in other words, it depends on how much leakage the ports allow, or how much damping is applied to them with acoustic mesh filters. The less leakage is allowed, achieved through use of less transparent acoustic mesh filters, the higher the SPL level under ~2000 Hz will be, with a very slight rise above it, and vice versa. Because LTA headphones are utilizing special acoustic mesh filters specifically designed for headphones and for this purpose, the results are very predictable and entirely linear, with no peaks or dips in the response. This means that simply changing the acoustic mesh that covers the tuning ports on the filter frames, or replacing the entire filter frames with those that have different mesh attached to them, is an easy way of manipulating the sound balance of the headphone towards a fuller or a leaner sound, is entirely reversible, and most importantly, completely unique, as no other headphone on the market offers a similar system.
    In addition to the filter frames, specific amounts of damping can be applied to the drivers themselves, either in the front, or the rear. Specifically speaking about the V2 drivers, the main port on the rear of the driver can either be uncovered, or it can be covered with one of the acoustic mesh filters that will be provided with the headphone. Depending on how much damping is applied to this port, the character of the low-end response of the headphone changes. The more damping is applied, the tighter the bass response becomes, with the peak of the bass response being pushed towards higher frequencies, and vice versa.​

    You can observe these effects on the frequency response graphs provided below.​

    [​IMG]

    The red line represents the stock configuration, with a very transparent rear driver damping filter, and a medium acoustic mesh on the filter frame, resulting in a well balanced response suited for a wide range of applications.

    The light blue line represents a configuration with the same medium acoustic mesh on the filter frame, but with a less transparent rear damping filter, which increases the tightness of the bass response, but also reduces the overall SPL in the low end of the frequency range, leading to a leaner, tighter sound signature.

    The dark blue line represent a configuration with the same, less transparent rear damping filter, but also with a less transparent acoustic mesh on the filter frames, which increases the overall SPL below ~2000 Hz, resulting in a tight, but more impactful bass than the light blue configuration, with a slight SPL reduction above 2000 Hz.

    Combining the effects of the filter frames and the rear driver damping allows one to precisely tailor the frequency response of the headphone, and these examples represent just a fraction of what is possible. The effects can be more or less pronounced, with very fine steps between various configurations, as there are many types of acoustic mesh filters available, there are 12 ports on the filter frame, and each can be covered with a different mesh. Whether you want more or less tightness in the bass, a higher/lower amount of bass, a higher/lower peak bass frequency, or a fuller/leaner overall sound signature, the V2 allows you to easily find the right configuration, with each step always being entirely reversible.

    As a result of that, it’s easy to imagine how beneficial this is in practice, because it allows one to change the response of a headphone in an entirely reversible way, and will enable future owners to simply swap between filter frames depending on what kind of sound signature they’ll prefer at any given moment, or even which drivers they’ll decide to install into their V2 headphone, effectively turning a single headphone into multiple ones by swapping affordable parts of it, and leaving 95% of the headphone untouched.​



    • EAR PAD REPLACEMENT
    Another way to modify the sound, but in a more extreme way, is to change the ear pads. The effects of changing ear pads are less linear and predictable than previously mentioned methods of tuning, as they introduce certain dips or peaks to the frequency response, which can be good or bad, depending on the type of sound signature one is aiming to achieve.

    Below, you can see the different frequency response effects depending on the type of ear pads used with the headphone. The headphone is untouched between ear pad changes, so the ear pads are the only variable between the graphs below. Combining the effects of ear pads with other modification options leaves one with an ability to endlessly tune the sound of the headphone. In my opinion, it's best to first find the right ear pad, based on the comfort, fit, and the general sound signature of the ear pad, and then use the other modification options to tune the sound to perfection. Whether your desire is a very dark, bass heavy sound, a V-shaped sound, a mid-forward sound, a neutral and flat sound, or an airy and bright sound, it's possible to achieve it while keeping most of the headphone components untouched.
    [​IMG]

    On the graphs above, you can also see that the peak located at around 8 kHz is entirely induced by the Beyerdynamic ear pads. No aftermarket ear pad I've tried caused this peak, but stock T1, DT770, DT880 and DT990 pads all caused the peak at the same exact frequency. It seems to be a characteristic of most Beyerdynamic pads caused by the hard rubber/plastic underside of the ear pads. This peak would generally be something that should be avoided, but I really like the way the headphone sounds and feels with the Beyerdynamic T1 ear pads, and the peak is nowhere near as present subjectively as it is on the measurements, so I suspect it's got something to do with my measurement rig as well. The peak on the DT770Pro is at the exact same spot too, but is actually audible when listening to the headphones. My guess is the position of the angled drivers relative to the ears is actually beneficial in reducing this peak, as opposed to the headphones sitting on the measurement rig and interacting with a completely flat surface.

    In addition to that, it can be seen that certain ear pads introduce more low end as well, which can easily be compensated for by simply using more transparent filter frames, as mentioned in the previous section. I didn't do that for these graphs, because I wanted to show the differences between pads alone specifically. However, using slightly more transparent filter frames in combination with the Brainwavz Hybrid pads, and in doing that tilting the entire FR below 2-3 kHz down a bit while maintaining the same curve shape, can lead to a FR that's very even from top to bottom, just like the graph with the T1 ear pads, but without the high frequency peak. I tried that, and it sounded great, however, I don't like the way the Brainwavz pads feel, as they have small 55 mm diameter openings, and my ears don't fit into them fully, which leads to slight discomfort. In the future, I'm planning to do the same test with Dekoni Hybrid pads, which should behave very similar to the Brainwavz ones in terms of sound since they're very similar in terms of materials and structure, but have a larger 60-65 mm diameter opening.​




    ULTIMATE VERSION OF THE LTA V2

    The final goal, as with other models, is to build the ultimate version of this headphone, featuring the most advanced Carbon Fiber reinforced Polyamide for the production of functional components, in a combination with CNC machined Aluminium structural and mechanical parts.

    Realistic renderings of such headphones can be seen on the website, representing what they would look like in the best case scenario. The hinge yokes, frames, and headband pieces are CNC machined, with Type 3 Anodizing applied to them, leading to a matte black, very finely textured, and extremely durable finish. The headband slider is CNC machined, and lightly brushed for a contrasting appearance. The ear cup grill is also CNC machined, with a laser engraved LTA logo, and a black polyester acoustic filter underneath it, giving off a subtle reflection based on the angle it's observed from. The center of the grill is brushed, with the exact same pattern as one on the headband slider, possibly with a mirror polished outer circular edge, which would be a luxurious detail that would additionally improve the appearance. The cup itself, as well as the rear headband piece, and the baffle frame, are made out of MJF PA12, with a nanosphere shot peened surface and a very finely textured, black finish. This means that the only two types of surfaces visible on the outside of this headphone are the CNC machined ones and the MJF PA12 ones, keeping the appearance very clean and subtle, but still undeniably high-quality. Of course, this is just one of many possible finishes. CNC machined parts can be polished, chromed, anodized in any color, brushed, etc. Possibilties are endless, this is just the appearance that I personally had in mind.


    Internally, the baffle, the filter frame, the driver holder and the hinge attachment pieces, are all produced out of the Carbon Fiber reinforced Polyamide, leading to the highest possible level of rigidity and potential for great performance with any driver and acoustic treatment combination, while still fully benefiting from additive manufacturing advantages and keeping the headphone entirely modular. Mechanically speaking, the main rotating hinge between the yoke and the slider features a CNC machined 4 mm diameter stainless steel shoulder screw, for extreme durability. This hinge, as well as the hinges between the yokes and the cups, are meant to be used with damping grease, leading to an ultimate level of smoothness in operation, similar to that found on high-end volume pots.

    A headphone built this way, would be as good as any on the market in terms of build quality, feeling of solidity, durability and a general perceived level of quality, while still offering a lot of possibilities in terms of functional characteristics, with plenty of sound tuning possibilities, regardless of the drivers or ear pads used.



    FUTURE PLANS FOR THE LTA V2

    I have a lot of plans for this headphone model, as it's extremely flexible. Several versions of the baffle have already been designed, with the drivers placed at 5, 7.5 and 10 degree angles, each with their own versions of filter frames. On top of that, baffles will also be available in those three varieties, but with 6 radial baffle beams around the driver instead of 12, for an even more opened character. New grill designs will be developed over time for aesthetic and acoustic purposes too.

    • A closed-back version of the cup will be developed as well, compatible with the rest of the parts, which will enable a simple transition from an open-backed to a closed-back configuration.
    • Other driver technologies will be employed as well if there will be an interest for that, with baffles designed for them, but still compatible with the rest of the headphone parts, making the transition simple and affordable.
    • The LTA V2 model will be available in form of DIY kits, as well as in several versions of fully built headphones.
    • Spare parts and upgrade parts will be available as well, such as various types of filter frames with specific acoustic mesh attached to them, each for a specific sound signature. This will allow owners to swap filter frames and end up with a different sounding headphone, while not having to modify the rest of it.
    • Upgrade kits will be available too, containing only the parts required to upgrade the headphone or change its configuration. For example, a kit containing a different pair of drivers, with the appropriate driver holders and filter frames with an appropriate acoustic mesh installed onto it will enable a practical way to upgrade or change a headphone. Owners will then have an easy task of replacing those components and turn their existing headphone into something completely different, without having to buy an entire new headphone. With more and more drivers coming onto the market, it's possible to imagine that in the future, owners will be able to vastly improve the performance of their headphone in a very affordable manner, and always entirely reversibly.
    [​IMG]
     
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  7. Tomislav_L

    Tomislav_L Facebook Friend

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    THE IDEA OF MODULAR HEADPHONES


    [​IMG]

    WHAT IS MY DEFINITION OF MODULAR HEADPHONES?


    As I've said already, my goal from the very start of this project was to design headphones that would offer possibilities that most other headphones on the market didn't, and that would give owners the ability to change their functional and visual characteristics whenever they felt like it, in a completely reversible and reasonably affordable way, without necessarily having to replace an entire headphone every single time they got bored of it or wanted to try something different, which has been the case in the past, and I'm sure most people reading are familiar with something similar.

    To simplify my definition of modular headphones:
    • They can accept several drivers, with an ability to adapt the headphone to each one

    • They offer an ability to manipulate the sound balance/signature while using a single driver

    • They can be customized in terms of aesthetics

    • Every part of the headphone can be easily removed or replaced

    • Everything done to the headphones has to be reversible
    I wanted to make headphones that would not just be single-configuration items, but future-proof and fully modular headphone platforms instead. I like to use the analogy of a PC here, as it's probably the best example of a complex platform with various possibilities. If I build a PC today, I can pick the exact parts I want and end up with a certain configuration, but at the same time, at any point in the future, I can replace specific parts to achieve different goals, wide a wide price and performance range available to me. I wanted that level of freedom and depth of possibilities from my headphones as well. In fact, this is particularly important when it comes to headphones, considering there's a lot of subjectivity involved, and they're very personal things.

    I knew that if I wanted this idea to be plausible, I had to do everything I could in order to make sure the headphones would be very DIY-friendly and easy to work on, with simple to understand modular design features that would give them a wide range of possibilities. Most importantly, modular features shouldn't introduce any fundamental drawbacks into the picture, and once built in any of the many possible configurations, the modular headphones should behave as if they aren't modular, but are simply great headphones instead. I've tried to apply these principles to every headphone I've designed as much as I could, and will do the same or even more when it comes to future models.

    The principles that I believe define what a modular headphone is, can be summed up into four points:

    1. Every single part of each headphone has to be removable, replaceable and upgradeable with basic tools, without any damage done to the parts that are being replaced, or to the rest of the headphone, with each process being fully reversible. You should never be forced to replace an entire headphone just because one part of them is damaged, faulty, or you've simply decided to change it or upgrade it.

    2. Every part has to be designed in a way that allows its production via multiple manufacturing methods, and therefore multiple materials, from affordable to expensive. This in turn allows for the creation of a variety of headphone configurations at multiple performance and quality levels, all while using a single basic design platform for each individual headphone model.

    3. The entire design concept of each headphone platform needs to be modular to such an extent that it enables several select types of drivers to be used with it, while featuring enough functional tuning options to actually allow the headphone to be adapted to those drivers, and offer high levels of performance with them. In addition, the modular features need to allow one to modify the sound of the headphone while keeping the same driver, by manipulating the sound signature and balance through modular passive elements.

    4. When switching between drivers, or keeping the same driver and playing with sound tuning options, as many parts of a headphone as possible should stay untouched, in order to make the modding process as affordable and simple as possible. Practically speaking, this means that each headphone platform features two groups of parts. The first group are the parts that represent the mechanical and structural elements of a headphone. They have little to do with the sound (to a certain extent) and should therefore be designed in a way that allows them to be reusable and stay the same regardless of the functional configuration of the headphone. Their job is to be as strong, durable, rigid and inert as possible. These are parts such as the headband pieces, adjustment sliders, hinge yokes, fixed parts of the ear cup, fixed elements of the driver baffle, etc. They are still individual parts, and can be replaced independently, but don't necessarily have to be replaced when upgrading the drivers or manipulating the sound signature. The second group are the functional parts, which have a direct influence on the sound of a headphone, and should therefore be designed in a way that allows them to be replaced or modified as required, depending on the desired results, and depending on the requirements of each specific driver. These are parts such as the removable filter frames, acoustic mesh filters, driver holders, ear cup grills, various acoustic treatment elements, etc. They are smaller, lighter, simpler and far less costly to produce than those in the first group, but have a massive effect on the sound of a headphone. As I've said at the beginning, this makes modifying headphones (once the basic structural parts are assembled) very efficient compared to having to build entire new ear cups or even an entire new headphone in order to achieve a different sound.


    WOULDN'T MODULAR HEADPHONES BE INFERIOR BY DEFAULT?

    A lot of people may think, due to the fact that an idea like this hasn't been fully explored in the past, that making a modular headphone that could work with various drivers and/or ear pads is impossible, or would simply never give positive results.

    Before going into why I strongly believe it is possible, I'd like to address the argument that something modular, designed to work in multiple configurations and with a lot of variables at play, is generally supposed to be inferior to something that's designed specifically for a single purpose and to work in a single configuration, with all the parts finely tuned to work together. That argument is correct. It is without a doubt a fact that developing a headphone (or any product) from ground up, and fine tuning every single aspect of it, should lead to the best possible results, at least in theory. However, it's not always the case in practice, especially when it comes to products like headphones, which are often highly subjective. It's actually virually never the case, hence the fact that pretty much no headphone ever created, at any price point, has been perfect and exactly matching the personal preferences of everyone out there, which is why there are large differences in performance levels, with a lot of different sound signatures between various headphones, even between those that are sold at the same price points. If making "the perfect headphone" was simple, or even possible, someone would have done it a long time ago.

    What I'm trying to say is that developing a traditional headphone with a fixed single configuration, doesn't lead to excellent performance and everyone liking it by default. At the same time, if properly designed, there is no reason why a headphone that offers modular aspects and a possibility to replace or upgrade its individual components would have to be inferior by default. It all depends on how well the headphone has been designed and engineered, regardless of whether it's modular or not. The point is that all of the characteristics that make certain single configuration headphones great are applicable to modular headphones too, but with the modular headphones having an added bonus of certain design solutions that aren't present on fixed configuration headphones. Therefore, if done properly, a modular headphone design can potentially allow for the development of multiple great configurations based around a single platform, with each individual configuration having all the characteristics of a great headphone, such as the use of high quality materials in its production, well designed passive headphone parts, high quality headphone drivers, a high level of attention to detail and great build quality, all while allowing for personalization of subjective aspects, such as the sound tuning in each of these hypothetical configurations.

    There are already headphones on the market that have taken this approach, to a certain extent. Take headphones such as the Sennheiser's HD6xx line. There have been multiple models in that line-up over the past 20+ years, all with a slightly different sound and a slightly different appearance, but they're all based on the same design, with the majority of their components being identical, but with different tuning options and aesthetic finishes applied to each headphone. Now imagine if you could have an HD650, but after some time decide that you'd like to try something different, and by replacing a single part on it, you could have the HD600 signature, without having to buy the entire headphone. And then you could change the sound signature again, and again, to an extent as extreme as you want, but always in an entirely reverisible way. That is the point of a modular headphone, and that's why a modular headphone is not by default inferior. It all comes down to the fact that people have different tastes and preferences, which change with time, and in order to satisfy their preferences at any given moment, they had to buy multiple headphones in the past. With modular headphones, that's not necessary anymore.

    Through this project, I think I've proven that headphones can be modular without any drawbacks introduced by the nature of modularity itself. Once they're built, they behave just like a great non-modular headphone, without the features that make them modular introducing issues or compromising the performance of such headphones in any way. Modular features are simply a massive bonus for those that are willing to make use of them.

    [​IMG]


    WHAT MAKES MODULAR HEADPHONES POSSIBLE?

    Making any headphone platform adaptable to various drivers, and allowing for multiple sound tuning options with a single driver, required a combination of some non-traditional and novel design choices, combined with some well tested principles that many high quality dynamic headphones feature.

    Based on my experience of playing with various designs, I've determined a couple of crucial elements of an open-back (or semi-open) headphone design that the overall "sound character" depends on the most.
    Identifying these elements was the first step, and allowed me to then start working on ideas of how to make those elements easily controllable and customizable, while keeping as many headphone components the same, in order for that headphone to be considered fully modular. Again, this is based on my experience, so take it with a grain of salt, because while the methods I'll describe have led to consistent and predictable results with all the headphone designs I've played around with, that doesn't guarantee the same would be true with absolutely all other designs. It probably would be, and it makes sense that it would be, but I'm not gonna claim that.

    To simplify it as much as possible, I'd like to divide those elements into five categories:

    1. The raw performance of the driver

    Obviously, this means that starting off with a driver that has good performance in isolation is very important, and the more linear the response of the driver is, with as few localized peaks or dips in the response as possible, the easier it is to manipulate its base sound character in a predictable way. Not every driver can be used for this purpose or is DIY-friendly, but the amount of them available that are is quite large. A lot of aftermarket drivers are developed to have a very even response, while some OEM drivers are developed to have very specific "tailored" response curves that only suit a specific headphone that they've been developed for, with built-in compensations for certain characteristics or drawbacks of that specific headphone design. Picking a driver that is suitable for a certain type of headphone design is obviously extremely important too. A driver developed for use in a fully sealed closed-back headphone, will never work properly in an open-back headphone, regardless of the amount of tuning done to it. Some drivers can be made to work equally well in closed and opened headphones, but they're quite rare. In addition, if the concept of modular headphones becomes more popular, it's going to attract more and more companies that can develop and produce high quality drivers to offer their products on the market. This already happened when Grado-like DIY headphones became popular, and has spawned many manufacturers of great aftermarket drivers, some of which perform as well or better than Grado's own top of the line drivers.​


    2. Controlling the position of the driver

    All of my headphone designs feature some method of attaching the drivers to the baffles at various distances to the listeners ear, most of them via driver holder parts, which are easily removable, cheap to produce, easy to design in various versions, and are usually designed to have multiple purposes, on top of just holding the driver in place securely. How far away from the ear the driver is can have pretty noticeable subjective effects, and probably easily measurable with the right measurement gear. In my experience, pushing the driver closer or farther by a range of 2 or 3 mm doesn't create major changes in the frequency response, but it does have certain subjective effects, making the sound "more forward" or "aggressive" the closer the driver is, and vice versa. Having an ability to adjust the position of the driver also helps when dealing with other variables, such as the shape of listeners ears, the type of ear pads used, etc. The angle and the forward offset of the driver also leads to certain effects, but the angles are fixed on current designs, in positions that I found best worked for me through testing. In the future model designs, I plan to make the driver positions and angles adjustable "on the fly", without removing them from the headphones, or having to replace any components. This is technically more difficult to pull off, but I have a pretty good idea of how to do it.​


    3. Controlling the venting of the enclosed ear pad volume

    One of the biggest aspects of being able to adapt various drivers to a single base headphone design, or manipulate the sound of a headphone while keeping the same driver, is the ability to control the venting, or the amount of leakage out of the enclosed ear pad volume. This is crucial for controlling the low to mid frequency performance of an open-back headphone, parts of the audible range that obviously have to be well tuned in order for any headphone to sound natural, as these areas of the frequency range contain most of the major information of anything we hear, regardless of whether we're listening to it in person, or through headphones. If this area is off, without an even and smooth frequency response, vocals won't sound good, instruments won't sound good, and at that point you might as well throw the headphone into the trash. For that reason, finding a way to precisely control the area up to around 2-3 kHz has been extremely important to me. I've managed to accomplish that with removable components that I call filter frames, which are at the core of all full-sized headphone designs I've worked on so far, and are one of the biggest reasons why this idea of modular, DIY-friendly headphones is actually possible in practice, instead of just being a nice sounding idea on paper.

    [​IMG]

    Now, a little theory behind this idea first, based on my experience with various designs and quite a lot of experimenting. Remember, I'm not claiming that any of this is solid science, it's still work in progress, and these are just my subjective and objective observations. As I've already mentioned, I found that the low to mid frequency response of any semi or fully opened headphone depends most of all (but not only) on the effects that the entire system of passive ear cup parts has on the amount of leakage, or venting out of the enclosed ear pad volume (let's shorten that to EEPV). To fully simplify this, we can say that the more leakage is possible, or the more "opened" the EEPV is, the lower the SPL up to ~2000 Hz will be, and vice versa. In addition to that, the actual physical volume, or the amount of air enclosed by the ear pad, as well as the shape of the EEPV, can have multiple effects, but more on that later. Now, controlling the amount of leakage, on any open-backed headphone, is usually done with a combination of two things:

    1. Ear pads – To simplify it as much as possible, the less transparent the ear pads are (eg. Leather), the less leakage they allow out of the EEPV, and therefore generally lead to higher SPL in the low to mid frequency region. More transparent ear pads (eg. Velour) will allow for more leakage, and will lead to a lower SPL in this region, if all other variables remain the same. However, ear pads usually have various other effects on the sound as well, throughout the audible range, and these effects usually aren't linear, leading to various dips or peaks in the response, sometimes quite nasty ones too. Which material is used for the ear pad, how much it absorbs or reflects certain sound frequencies, how perforated it is, how large the perforations are, how dense the foam inside of it is, how well the pad sits on the head and how well it seals, how deep the ear pad is, and how large the ear pad opening is, are just some of the variables that all add their own little contribution to the sound. For that reason, relying on ear pads alone to tailor the sound of a modular headphone is more or less a game of trial and error, and will rarely lead to desired results on its own. When making a single configuration headphone that's not meant to be modified in the future and that will only use a single type of driver, designing an ear pad to tailor the sound in a specific way is possible, but we're talking about modular headphones here. So relying on ear pads alone is impossible.

    2. Baffle ports
    The other way of controlling the leakage out of the EEPV are the ports on the baffle surrounding the driver, which vary in shapes and sizes from headphone to headphone, and are covered with filters that have a certain acoustic impedance rating. Paper filters are usually used on most headphones, because they're cheap and can do the job in most cases, especially when the ports are fairly small relative to the overall area of the baffle. The better way of doing it, and this is how most dynamic high-end headphones do it (HD800, HD700, T1, K812, all Focals, etc.) is to make the baffle ports as large as possible, and then cover them with more advanced, but more expensive, metal or polyester acoustic mesh filters. Acoustic mesh filters are specifically designed for use with headphones, have very linear effects on the frequency response, and are available in a wide range of acoustic impedance ratings, from very transparent, to very dense, making it very easy to find the right filter for any application. I've been using such filters by SAATI. Now, making the openings on the baffle very large, also means that the design of the baffle has to be quite complex, with a lot of structurally beneficial design elements and bracing, combined with high quality materials, in order to ensure that the baffle is rigid and inert enough, keeping the impact it has on the sound of a headphone to a minimum, and allowing the driver itself to shine. At the same time, the baffle itself can't be too heavy. It would be easy to make a perfectly inert baffle by just laser cutting a 1 cm thick piece of steel and drilling some venting holes in it, but the headphones would be unbearably heavy.

    In addition, this design principle has certain other benefits as well. Logically, the larger the ports on the baffle are, the less solid plastic/metal areas there are to reflect the sound back. Keeping the baffle as opened as possible also leads to a subjective sensation of a more opened sound because it's possible to hear the surroundings, and there's less heat build-up as well, leading to more comfortable listening sessions.

    All of this means that controlling the low to mid frequency performance of the headphone is best done by relying as much as possible on a combination of the baffle, the ports and the filters, rather than ear pads alone.

    However, deciding on the design direction only solved half of the problem, because replacing acoustic mesh filters on headphones such as the ones I mentioned above is impossible without permanent damage. This meant that I had to design a headphone in such a way that replacing filters would be quick and simple while also following this design direction. I wanted the ability to replace filters with no damage done to either the filters or the rest of the headphone, with the process being entirely reversible, and without introducing any downsides to the performance or the rigidity of the entire assembly. The best solution I could come up with for that are multi-layered baffle designs with removable filter frames.

    Since the filter frames are easily removable, and very cheap to produce, costing a couple of dollars per unit to make, they can be replaced in order to change the sound of a headphone to a larger or lesser degree, depending on the design of the filter frame, and the acoustic mesh used with it. In short, the more transparent the mesh is, the lower the SPL up to ~2000 Hz is, combined with a very small boost in the 2000-4000 Hz region, and vice versa. Steps in acoustic impedance levels between various types of mesh filters are very fine, so it's easy to find just the right balance. On top of it, baffles have multiple ports, so it's possible to use a combination of various mesh types at the same time, leading to even finer degrees of sound tuning. In my experience, the effects are very linear and predictable, the shape of the FR curve in that region doesn't change when replacing one mesh with another, and there are no peaks or dips introduced. The only things that change are the tilt and the level of the FR curve, with the effects becoming gradually more pronounced towards the lower frequencies. It's basically like a physical equalizer. This is the case regardless of whether only the filter frame is being changed, or the driver is being replaced as well. So, the method of replacing filter frames is not only useful for adapting a base headphone design to a different driver, but for customizing the sound of a headphone without changing the driver, enabling a transition to a different sound signature by simply swapping the filter frames, and nothing else. It's like having the HD650's, and then after spending 5 minutes to replace a few cheap parts, you end up with the HD600's, but with many more degrees of tuning possible in either direction of the sound signature spectrum, and without having to buy another pair of headphones each time you want a different sound signature.

    Alternatively, I've tested a method of using a certain amount of smaller ports on the baffle, opened or closed with a sliding mechanism, however, this allows for a far smaller range of adjustment, and takes away space that could be otherwise used, ultimately making the headphone more complicated with limited benefits. However, it is an idea I'm exploring and could possibly combine with removable filter frames in certain future designs.


    - How additive manufacturing helps in this case?

    Now, using a multi-layered baffle is only possible if the fit between the filter frame part and the main baffle part is extremely tight, eliminating any possible rattling, noise or any unwanted structural losses in general. Luckily, the dimensional accuracy of SLS or MJF 3D printed parts is extremely high, enabling very tight assembly tolerances or gaps between parts, which means they fit together very tightly, but can still be separated without any damage. On top of that, all the polyamides used by these AM technologies are very "silent", they don't rattle and they don't squeak like ABS plastic can, for example, because of their slightly "soft" surface feel. Once the parts are assembled and all of the screws tightened, filter frames and baffles essentially act as a single solid part, with a very solid feel. In fact, without knowing about it, it would be very hard to tell the parts are layered.



    4. Controlling the shape and size of the enclosed ear pad volume

    Since the filter frames are now removable, and since they essentially represent the "upper layer" of the baffle, so they define the size and shape of the EEPV to a certain extent, another modification becomes possible. As I've mentioned previously, changing the volume enclosed by the ear pad has an effect on the low frequency performance. Again, in my experience, the larger the volume is, the higher up the frequency range the bass peak is pushed, and vice versa. This means that changing the designs of the filter frames in order to make them thicker, or thinner, is a simple way of either increasing or decreasing the EEPV, and therefore control the peak frequency of the bass response. In addition, since the shape of the filter frame/baffle has an effect on the sound as well, primarily on the 3000-5000 Hz region in my experience, changing the design of the filter frame part, or modifying how "concave" or pronounced the "bowl shape" of the baffle is, enables a bit of control over the frequency response in the highs. However, the higher in the frequency range you go, the more difficult it becomes to control the sound, and the more you depend on the characteristics of each individual driver and the peaks or dips introduced by specific ear pads, earlobe shapes, etc.

     
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  8. Tomislav_L

    Tomislav_L Facebook Friend

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    5. Controlling the acoustic chamber behind the driver

    The last major aspect of tuning a headphone is dealing with what happens behind the driver, All three of the headphone designs that I'll present, despite all being fundamentally different in terms of design, offer an ability to control the rear acoustic chamber in four main ways, by allowing me to:

    • Control the volume/shape of the chamber – This is possible by utilizing various custom pattern designs of the chamber walls, including 3D printed adapters with complex patterns that can be inserted into the default chambers, or by lining the walls of the chambers with materials of varying degrees of thickness.

    • Control the reflective/absorptive properties of the walls of the chamber – The methods mentioned in the previous point can be used for this purpose as well. Lining the walls of the chamber with a certain type of felt, or foam, will produce different results than leaving the walls exposed, with a smooth plastic surface. Various irregular patterns can be designed and featured on the 3D printed inserts too.

    • Control the degree to which the chamber is opened at the end opposite to the driver – This aspect can be controlled by using various filters, felts, foams or fabrics, in combination with grills of different designs and various degrees of openness covering the ear cup holes. Of the four points mentioned here, this one has the most dramatic effects in most cases, allowing to entirely transform (and sometimes ruin) the sound of a headphone just by adjusting this single variable. Anyone who has used an open-back headphone like the K701's and covered the grills with their hands, knows how big the effects on the sound can be. Using less opened grills doesn't just "choke" the amount of airflow available to the driver, but it can also lead to more reflections from whatever is blocking the openings. For that reason, I generally like to keep the rear chambers as opened as possible, with very transparent grill designs (at least 60% open area), and then use acoustic filters to control the airflow, if that is necessary to begin with. In some cases, it isn't, and leaving the grills alone leads to good results. As for the effects on the sound, in my experience, blocking the rear grills on V1 and V3 models leads to a gradual increase in the 2-4 kHz region, while gradually making the bass tighter. Blocking the grills past a certain degree leads to an exaggerated mid-high region, gradually spreading the effect over a wider frequency range, combined with a gradual reduction in the low-end performance, leading to an overly stiff and rolled off bass. At the same time, with some drivers, leaving the rear overly opened can lead to a somewhat bloated low-end, lacking in control. It's a matter of fine balance, but luckily, it's very easy to find that balance, as the effects of using acoustic filters to block the ear cup openings are predictable and consistent, just like when using them on the baffles. Additionally, blocking or opening the ports on the back of the drivers themselves, which are usually covered with acoustic filters (paper, mesh, felt...), can lead to similar effects, but IMHO it's best not to touch those filters, unless absolutely necessary, because it could lead to irreversible damage.

    • Control what happens within that volume of air in the chamber – Precisely, dealing with the standing waves in the chamber behind the driver, since sound waves are obviously emitted from the back of the driver as well. For this purpose, if required, certain porous or fibrous materials can be used to fill the volume of the chamber to a certain extent, in order to break up the standing waves. Using certain types of foam, or even better, stuff like polyfill, specifically designed to deal with this issue in speaker boxes, is usually very effective, simple and affordable. This isn't particularly useful for tuning the sound balance, but instead for dealing with certain possible issues (narrow peaks at specific mid to high frequencies) that could arise with certain headphone designs, especially those with relatively long, cylindrical rear chambers.
    [​IMG]

    WHAT DOES ALL OF THIS MEAN?

    It means that it's entirely possible to have a single base headphone design that can work with several different drivers, which require slightly different environments in order to function optimally, because now all of the crucial sound tuning elements can be modified while keeping the majority of the headphone components untouched.

    Because of this, it's possible to not only fine tune the sound of a headphone, and achieve different sound signatures when using a single driver, but even after building one configuration of a headphone, it's possible to keep most of the "expensive headphone parts" the same, put an entirely different driver in it, and still have the ability to adapt that headphone to function properly with that new driver, by simply changing the "cheap headphone parts". This is great because it's not only fully reversible, but is also far more efficient and affordable than changing the entire main baffle, or the entire headphone. The best part is, the amount of headphone drivers available is enormous. Even if we just limit our choices to the "Grado mod drivers", the 46 mm diameter ones, there's multiple high quality choices on the market. Expanding to the entire aftermarket driver industry, there are literally hundreds of choices at various price points. And at the end, there are the OEM drivers, since pretty much every major headphone company sells their own proprietary drivers as spare parts, so it's possible to build custom headphones using them as well.

    It also leaves us with some interesting implications regarding the potential life-times of such headphones, the possibilities to gradually change or upgrade them in the future, replace parts with new updated and improved versions, replace them with parts produced out of higher quality materials, maybe made with some newly developed additive manufacturing technology that's yet to become available. The possibilities are literally endless.
    Of course, theoretically, it still takes a lot of work to develop a modular design that actually works in practice. But, as I've said at the start, my idea has been to design fully modular, DIY-friendly and future-proof headphone platforms that could serve me well for years, and I think this comes quite close to what I've had in mind. Does it require more work than simply going into a store and buying a headphone? Sure. But it's damn fun to play around with, and that's what headphone DIY should be all about. Especially when it's possible to end up with good results, while potentially saving money.






    ---------------------------------------------------------------------------------------------------------------------------------
    FREE ACCESS TO 3D CAD FILES

    [​IMG]


    THIS MAY SEEM LIKE A BAD BUSINESS DECISION...


    ...or it may just be so insane that it's impossible to ignore.

    Right now you're probably thinking why in the heck would I spend over 3 years, over 2000 hours, and thousands of dollars on a project like this? Why would I go through the effort of learning all those skills from scratch, doing so much research, developing new design methods and concepts, experimenting with manufacturing technologies and materials previously unused in the headphone industry, developing a complex post-processing method for 3D printed parts, creating an enormous amount of written mateial, taking thousands of photo's and making hundreds of 4K renders, filming hours of videos, building a huge website...and then finally, as a cherry on top, why would I release the 3D CAD files of the final products into the public and give everyone free access to them?

    Well, in my mind, as someone who dreams of having his own headphone brand, but is currently unknown and doesn't yet have a reputation of someone who designs and builds headphones, there is no better way to earn the trust of the community and gain that reputation than by actually sharing those designs and headphones in the most interactive, insightful and direct way possible.
    Especially when we're talking about completely modular headphones which offer possibilities that no other headphone does and have been specifically designed to be easy to customize, hopefully resulting in all sorts of unique builds by the community. It's also fair to give something back to the community, a way to thank the members in advance for hopefully getting involved, spreading the word about the project and helping it turn into something bigger. In doing that, I hope that at least a part of the headphone community will understand how much work went into this project.

    I also want to use this as an opportunity to show my potential and give people a hint of what's coming in the future.
    Whether people like my work or not, they're bound to ask what's coming next. I'm already working on several new headphone models, and I have a lot of plans for the future, a lot of far more extreme design concepts to explore and more modern manufacturing techniques to utilize. The more attention the project receives, the quicker I'll build the reputation, which is crucial for me to be able to continue doing this. Now it's only up to the headphone community to decide what comes next and it will all depend on how many people there will be around who will really want to see this project have a bright future.

    In addition to that, I really want this to be an interactive project unlike any other in the headphone community, that will actively involve its members and enable like minded people who share the passion for this hobby to swim up to the surface and show what they can do. I want the DIY headphone community to wake up and grow, because I know there are a lot of people out there who know they have the creativity, but don't know where to start. In general, I want people to realize that we live in a time where they can have more control over the products they use than ever before, including designing them and building them from scratch. If you have the creativity and the determination, you can do it, because all other tools are already available.



    WHAT HAVING ACCESS TO CAD FILES MEANS FOR YOU

    Quite simply, it allows you to skip a huge amount of work, R&D and save a lot of money, as I've already gone through the hardest stages of the process of developing a new product - forming the ideas, making concepts, doing the required R&D, designing the actual products in multiple iterations, doing a lot of testing, making functioning proof-of-concept prototypes and planning out the entire manufacturing process down to the last detail. You can simply skip most of that and go straight to the last stage, the manufacturing.

    You can use the CAD files in any non-commercial way you can think of.
    You can modify them, redesign them, build the headphones using the designs as they are right now, or build them using modified designs. You can add parts, replace parts, etc. I will also continue to improve the designs over time and continue to add new versions of certain headphone components. My goal is to enable people to build high-end worthy headphones for mid-end prices, and depending on materials, drivers and accessories, it's possible to build V1 or V2 headphones for anywhere between 400 to 800 dollars, which, when all things are taken into consideration, makes them great value for money, and when built properly, easily competitive with headphones at twice the price. Obviously, if you're gonna make a single headphone, it's gonna cost a bit more, since the economies of scale will affect your project, but that's to be expected. You'll also most likely have to go through a couple of iterations and some trial and error.

    If you want to redesign certain parts, and have special requirements, another option is to let me know about what exactly it is you need, and I can help you out with the design and manufacturing.

    If you want to use these designs for commercial use, you can contact me we can find a way to collaborate, but yes, in theory you could even use these designs as a basis to build your own line of headphones, and then sell them for whatever price you choose. This is certainly something unprecedented, but I hope it triggers a spark in people who are interested in some more serious DIY work, but don't know where to start. Who knows, this project might turn into a headphone equivalent of the O2 headamp, with multiple variations of the basic design available on the market, made by various builders.


    [​IMG]

    MANUFACTURING THE HEADPHONE PARTS

    It's up to you to decide how you'll manufacture the 3D printed parts, but it's important to remember that these headphones have been designed with industrial Selective Laser Sintering and Multi-Jet Fusion additive manufacturing technologies in mind, which have virtually no design rules or restrictions, require no supports for overhangs or hollow parts, are extremely good at producing very complex parts with a high level of dimensional accuracy, and do so out of the most advanced 3D printing materials out there, resulting in parts that have extreme mechanical properties, far superior to ABS plastic parts found in most headphones out there, as well as an excellent surface finish, with great chemical and thermal resistance. Crucially, they're also very suitable for post-processing, which is an important part of making these headphones feel like high-end items. These industrial additive manufacturing technologies are not a replacement for traditional manufacturing, in fact, they're upgrades, this has to be clearly understood. More affordable FDM or SLA 3D printing methods are replacements and enable you to make "good enough" prototype parts for certain applications, SLS and MJF on the other hand exist for the sole purpose of producing high performance plastic parts for the most demanding industries. We're not using these technologies to save money, instead we're paying extra and using them to produce better parts than we could with traditional methods. Therefore, it's guaranteed that these parts will have proper mechanical properties when produced using these technologies, but I don't know how far off they'll be when produced using inferior 3D printing methods such as FDM or SLA.

    I know a lot of people have FDM or SLA printers, but it's important to understand that those technologies operate entirely differently compared to SLS and MJF, both need to print supports for overhangs and hollow parts, suffer from warping and dimensional stability issues due to differential cooling, and their materials aren't as durable or mechanically versatile. In essence, they're not industrial-grade technologies, they're good for hobbies, but for anything more serious, you're always in unknown territory. Therefore, I can't guarantee the parts will fit together properly without additional design modifications, whether some of the more complex 3D shapes can be printed at all using those printers, and I don't know how strong the parts will be when printed out of certain materials, you'll have to go through some testing on your own if you decide to go on that route. I also can't guarantee you'll be able to install thermoplastic threaded inserts, use self-tapping screws or post-process the parts properly when produced out of some FDM materials and most SLA materials, as they have various thermal and chemical properties, so make sure to use proper materials.

    What I'd strongly recommend is sticking to SLS and MJF
    and using the services of some consumer oriented company like Shapeways, Sculpteo or iMaterialize to have the parts produced, unless you have 150-300k USD laying around to buy yourself an SLS or MJF machine. :)


    [​IMG]


    KEEP SOME THINGS IN MIND BEFORE STARTING A DIY PROJECT

    Don't let this scare you or put you off attempting to work on a DIY project. It's just that having access to 3D files puts you at 50% of the way to holding the headphones in your hands, and in order to get through the other 50%, you'll need to figure certain things out on your own depending on the direction you want your headphone build to go in. Building your own headphone from scratch if you decide to manufacture the parts and source all of the accessories on your own is challenging and requires a lot of work, but remember, it's still far less work than having to design and develop the whole thing from scratch as well. You can read more about things to look out for in the PDF file, or contact me if you'll need help.



    WHAT IF YOU DON'T WANT TO MANUFACTURE PARTS ON YOUR OWN?

    If you're not feeling like working on a project of that level of complexity, and don't want to go through the trouble of manufacturing parts on your own, you can always contact me and I'll help you source parts the same way I do it for myself, including giving you an option to get DIY kits, at prices that are in most cases going to be quite a bit lower than what you'd spend by manufacturing things on your own anyway, and with guaranteed best available part quality and the best available materials, as I've already gone through the process of having parts made by various companies until I discovered what worked best, and can get special prices because I've made a few valuable contacts in the additive manufacturing industry in these last few years of constant prototyping and making a huge amount of parts.

    If you're not interested in DIY kits either, but would still like these headphones built specially for you, that possibility exists as well. You can currently get these headphones built for you at the absolute highest level of quality, out of the best materials available, meticulously post-processed by hand and for a price that's lower than what you're most likely going to spend on building a headphone from scratch on your own, because I can avoid the trial and error phase of manufacturing. I have the entire building process sorted out already, know exactly what to do, and for that reason, every headphone I'll work on for each individual client will always be built to the highest level of quality. Later on, you can still make use of the CAD files and redesign parts, or have individual parts manufactured in updated versions in order to upgrade or customize your headphones, but you don't have to bother with building the whole headphone at once if you don't want to.
     
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  9. Tomislav_L

    Tomislav_L Facebook Friend

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    [Reserving reply for future updates]


    Whew that was a lot of text. I'm hoping it's not overwhelming, but this is just a small part of it and I've tried my best to section the content so it's at least sort of easy to navigate through. I won't post any new massive walls of text for now, and I leave it to the community to give me impressions, opinions, criticism, suggestions, etc. Feel free to ask anything and I'll try to answer ASAP. Hopefully we'll soon see some headphone builds by the community as well.
     
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  10. Walderstorn

    Walderstorn Friend

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    Will you have prototype of the hd600/650?
     
  11. Tomislav_L

    Tomislav_L Facebook Friend

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    You mean a prototype with HD600/650 drivers? I haven't done anything with those drivers yet.
     
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  12. spoony

    spoony Spooky

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    Had something like this in the backburner for a while, now I won't have to do finish it! Huge, huge props!
    Due to the sophisticated additive manufacturing required for the parts, I would think that a logical next step is to have your prototypes in a loaner tour to gather encouragement from this community and have more people jump into the bandwagon.

    Any comments on the R1 drivers from Elleven?
     
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  13. Taverius

    Taverius Smells like sausages

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    Holy info dump batman, you certainly put a lot of work into this project.

    As to the poll & associated questions, while the idea of DIY kit sounds fun, that'd be only if the parts came surface finished, because I already do finicky surface finishing at my day job.

    And at that point I might as well have someone who knows wtf they're doing assemble it.

    Also, none of the prototypes you've shown attract me, because to me the only sane response to suede on my skin is "just say no".

    Messing about with filter materials and whatnot is one thing, but fucking about with pads myself would balloon in costs too fast for my liking.
     
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  14. Tomislav_L

    Tomislav_L Facebook Friend

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    Yea, I'll definitely try to get the prototypes to people who'd be interested. For the last month or so they've been in Portland at Mouser's because I had to ship it to them for inspection before the crowdfunding campaign, but I should get them back in a few weeks, maybe I'll be able to sort out to have them sent directly to someone in USA, although I have no clue what kind of condition they'll be in in that case since who the hell knows what they did to them, whether they disassembled them, etc. Might be better if they get to my hands first to make sure everything is ok. Meanwhile I hope I'll get to build a few fully refined and finalized production units for some people, and if I'll manage financially, put together a production unit or two specifically to send them out to people for reviews.

    Also, yea, the additive manufacturing is expensive, but I'd encourage people to give it a try, at least have a part or two printed for a few bucks to get familiar with the advantages of these materials, lots of AM companies have major discounts around this time of year too, be sure to check out Shapeways and a few of the bigger names for special offers, free deliveries, etc.

    As for the R1 drivers, I have limited experienced with them, only tried them in Grado-like builds, and in those I prefered the P1's and stuck with them, so I have far more experience with them. P1's are a bit more expensive, but IMHO in some ways one of the best dynamic drivers I've tried. Especially for vocal and instrumental stuff, which as I said in the post, they excel at and I have a hard time thinking of a dynamic driver that does it better. Certainly not the HD800 or the T1 that I've tested a lot (and owned for 5 years in case of the T1). It's one of the reasons why I sold the T1's after a long time, every time I put them on after a V2 build with P1 drivers, I felt like the mids were super dull and I couldn't enjoy the music I mostly listened to anymore, so off they went and financed a part of this project. P1's (and judging by measurements R1's as well) do have some "issues" though when used in full sized builds, mostly in the lack of the low end extension compared to some of the latest and greatest dynamic headphones. Not that they lack bass (and can be tuned to kick like a mule while still being relatively tight and controlled), but they do start rolling off sooner than I'd like with some music.
     
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  15. Tomislav_L

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    Yes of course the parts in kit could be surface finished, that's a major part of putting these together and requires special equipment and space (especially when working with 2K paint products which is a big health hazard without proper spray booth ventilation, full body suit and a proper respirator), so that would definitely be something I'd offer, either as an option, or by default. Hopefully in the future CNC machined aluminium parts that will already be anodized, brushed, or with whatever finish straight out of a factory will be a thing, so there will be no need to paint stuff at all. But that will require me to work with larger quantities, as just CNC machining parts for a single headphone at a time costs around 1200€ if done in Europe, or about 800 in China, so, no. :) With 5 units though, that cost drops to ~400, and that's sort of acceptable already.
    My idea for DIY kits is to offer the building experience as smooth as that of building Lego's, if that makes sense. :) No hassle, no unwanted surprises or guessing. Everything needs to fit perfectly and work as intended on the first attempt, but that should also be the case if people actually produce parts on their own using the CAD files.

    So, you don't like suede (well, velour in this case) pads? I guess we're in opposite camps, because they're the only ones I can tolerate on my face, hate the feeling of leather. But, that's the advantage of being able to replace them. In the future I will put together a "data base" of sorts with several configurations of headphones each with a different pad AND appropriate combination of acoustic filters and acoustic treatments, to counterbalance the effects of the pads and end up with a decent sound signature. So those configurations will also be usable as examples or "plans" to build DIY headphones after, and to not have to experiment too much, because I get it how it could be overwhelming to go and attempt to voice a headphone without even knowing where to start.
     
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  16. Taverius

    Taverius Smells like sausages

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    It very much has the "prickly wool sweater" effect where I want to rip them off my head in less than 30m.

    Also I'm an oily sweaty Italian and suede, velour and naked foam - grado pads - become ick at unreasonable speed.
     
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  17. Tomislav_L

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    Yea I get what you mean, not a huge fan of exposed Grado foam either, but they're not that bad once I got used to them and they just lead to better sound than any similar aftermarket pads IMHO, and they can be washed easily. I wonder why none of the big aftermarket ear pad companies don't make grado-style pads but actually covered in some material. Velour does get nasty with time, I admit that, that's why I wash my silver DT series Beyer pads 2-3 times a year, soaking it in soap seems to help the foam "bounce back" to a somewhat original shape as well. However, the T1 pads have a slightly different material, it's not as "fuzzy" as the silver DT line ones and the whole pad feels "more expensive" (and is), which is why I picked it for this project, and also happens to sound the best overall to my ears. There are some great pads out there though that I have to still try out. I tried the entire line of Brainwavz rounds, and like the Hybrid the most for sound and feel, but the openings are still a bit small for my huge ears. Gotta get my hands on some Dekoni pads, but I'm having a hard time agreeing with the 70-80$ price tag at the moment.
     
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  18. señorhifi

    señorhifi Acquaintance

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    Whoa, that's a lot of info and the first FR graph looks impressively flat! Money wise, here's how I am looking at this:

    -it gotta be at least as good in detail retrieval as the HD6X0 line up and improve those headphones somehow (better bass, soundstage, or speed).

    -The price shouldn't go over 500€ total for a DYI Kit with all required parts so you can make it at home. If it goes higher than that (say 1000€ for everything), it'll be a hard sell. I have a hard time imaging people buying some new DYI kit over some other TOTL around this price (be it new or second hand). Price thess according to sound quality. Remember that at 500€ you compete against the HD6X0 line up, the K712, the Sundara, the Koss electrostatic hp and the DT1990 (albeit that's garbage so no big deal). At 1000€ you compete against the LCD2 Classic, the Focal Elex (not sure but maybe even Clear?) and the HD800S (it's a bit more expensive though). With a DYI kit you gotta blow that competition away depending on how you price them.

    - Materials must not look DYI, but high quality and factory made. I would hate to see 3D printed plastic or roughly cut aluminum. The assembly should be smooth and gap free and once assembled, it must not look in the slightest like a DYI kit. I think you got this figured out though. Those headphones look awesome!

    My main point is, if you won't be able to improve on the HD600 sound in terms of detail retrieval or somehow else, it will be hard to sell. Why buy an expensive DYI kit, if the 300€ HD600 is better, right? Mind you, the K712 is only 220€ in EU and the DT880, 150€. If you're gonna release the Kit, this must sound TOTL (or get close) and be around 500€ to maybe 750€. I won't spend that much money on something that's not great, keeping in mind how awesome things can be at 300€ or less. Hope this helps somehow.
     
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  19. Tomislav_L

    Tomislav_L Facebook Friend

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    You're correct, I've had all those things in mind when working on this project, and have been very cautious all along the way with what was already on the market and at which prices, and your assumptions in terms of pricing ARE in fact quite similar to what is currently (with the cost of 3D printing, CNC machining, etc.) possible to achieve.

    The V2 kit, with the best plastic materials (carbon fiber reinforced PA), with parts post-processed (to better quality than seen here, these are after all just prototypes and the V2 parts have been disassembled and assembled dozens of times and "thrown around" for over a year, so the clear coat is not in the best polished condition anymore), with drivers and all accessories included (like a built cable with original Hirose and Neutrik connectors, Beyerdynamic ear pads, all screws, etc.) could be made and sold for around 450-500€. Less than that without a cable, without post-processing the parts, like 100€ less, and potentially even less than that with more affordable materials, avoiding the exotic carbon fiber reinforced stuff. I agree that kits should not feel like kits, or DIY headphones look or feel like DIY headphones, that's high on my priority list, and when I post-process parts, I really aim for a perfect finish, you can see the whole process on my youtube videos, there's a whole series of post-processing guides. There should be zero worries about fit and finish or quality, I'm super sensitive to parts not fitting together properly, things feeling loose, creaking, etc. Pleased to say I've worked out all of those issues with super tight tolerances so even the prototypes feel very solid and substantial. If and when I start selling the V2, my goal will be to NOT go above 550€ maybe 600€ max with a top configuration and best materials, for a fully built headphone, which I think would be a SUPER fair price considering the performance, exotic materials, amount of precise hand work involved in post-processing them, the fact that they're modular and can be upgraded, customized, etc. in ways other headphones can't, so it's a more "future-proof" investment since you can change the sound signature in the future, upgrade parts, put in better drivers, etc. On top of that, about 50-60% of the parts cost-wise are cross-compatible between the V2 model and V3 model coming out soon, so it's gonna be far cheaper for someone who already built the V2 to build the V3 and reuse a lot of the parts. In case of using CNC machined parts, that would simply have to go up by an additional 100-150€, it's just impossible to pull off CNC machined parts at prices near the cost of 3D printed ones unless making 100's of units at once.

    As for the performance and comparisons to the HD6xx line. I think both the V1 and V2 don't have any issues against the HD6xx line (or any headphone in that segment like the K701, DT880, etc.). I've owned 3 pairs of HD600's and 2 pairs of HD650's over the last 10 years. Love them, sold them many times to try something else, went back to them, and so on, so I've got a lot of experience with them, and I'd still own a pair of HD600's if I wasn't working on this project and had to sell them. I've also owned the K701's (original made in Austria) and the newer made in China version, and a full line-up of Beyers, all 3 impedance varieties of the 770Pro's, DT880 600's and DT990 Pro's and 600's, and most importantly, the T1's, which have been my reference dynamic headphone for the past almost 6 years, until I was forced to sell them for financial reasons (read: this project was expensive). So, I went into this project with a lot of experience with headphones in the price range I intended what I was working on to be competitive in. Before I sold the T1's, I did a lot of listening comparisons between the V1 and V2 prototypes, and the T1, and only sold the T1 once I felt like what I was working with started showing potential to be good enough to replace them. I may be biased, despite how hard I try not to be, but it's a reason why I kept working on this project despite spending a lot of money on it, having to sell a lot of my beloved gear to finance it, and having spent more time working on it than I'm ready to admit. If I wasn't entirely confident that the project had potential, I would have given up on it a long time ago. :)

    Bottom line is, biased as I may be, but also experienced and extremely self-critical, I'd rank the V1's and V2's closer to the T1's than I would to the HD600's for example, knowing each of those headphone inside and out and having lived with them for a long time. Not much to say about the V1's, anyone who tried any Grado-like DIY build with the Elleven Acoustica drivers knows how good those drivers are, it would almost be an art to make them not sound great. The only thing the V1 does is it provides a very solid platform to build from. For my tastes, I like the entirely inert and rigid approach of the V1 more than the traditional "tone wood cup approach", but understand how someone would prefer woodie build with the P1 drivers, it's totally down to personal preference, but the V1 does make tuning easier than a traditional woodie cup, since it can be taken apart once it's put together and there's no glue involved in building. And by tuning in this case I mean just increasing or reducing the volume of the chamber behind the driver, lining the walls with damping materials, putting various amounts of speaker cabinet damping material into it, and messing with how transparent the filters under the rear grills are, so very much a "trial and error until you find what you love" thing. But that's what makes DIY fun.

    The most similar headphone to the V2 built in the configuration shown here would be the Aurorus Borealis, in terms of technical ability I guess, considering both headphones use the same drivers (and same ear pads if one chooses to). I haven't listened to it, so I can't speak about it, however, on paper the V2 has an advantage of significantly more rigid baffles made out of carbon fiber reinforced PA instead of ABS, with more complex baffle designs which "should be" acoustically superior, with angled drivers, and acoustic mesh filters by SAATI on the baffle ports (same line of filters, not necessarily the same spec of acoustic impedance, used by Focal on their TOTL's, HD800's, T1's, etc) instead of steel mesh cloth. It can also have a lot of the parts CNC machined as well, like the outer frame of the Borealis. Of course, a recipe doesn't guarantee the food will taste good, but based on the recipe alone, the V2 must be AT LEAST on par in terms of performance in a strictly technical sense. Of course there's still a matter of tuning to personal preferences, graphs relative to the DT770 show how I've chosen to tune mine, but that's a type of costumization made easy with the V2 as well due to being modular. So someone building one would have a lot of freedom to play with the sound, starting off with that foundation of combining proven and great drivers with a really rigid passive "shell and body" of the ear cups.

    That's why I'm so excited to have people try these out and am currently working towards making that possible ASAP.
     
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    Last edited: Dec 9, 2020
  20. Argopo

    Argopo Facebook Friend

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    Tomislav, thank you for posting this.

    I'm interested in this project. But, I won't want to do the DIY build. (I'm currently preoccupied with a DIY differential headphone amp project.)

    It seems the way to order a pre-built V1 or V2 unit is through the crowd supply site? Or can I DM you to work out the details.

    Thanks! And best of luck with this project.
     

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