Personalized Equalization with in-ear mics

Discussion in 'Computer Audiophile: Software, Configs, Tools' started by randomg, Nov 16, 2016.

  1. ultrabike

    ultrabike Measurbator - Admin

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    As far as angling the driver, I believe that the HD600 drivers are not angled, but the HD558 are. The signatures are similar though with the HD5x8 family having more distortion but lower impedance (easier to drive using voltage limited sources). That said, a driver not properly seated in the HD600 enclosure will sound awful. So driver localization and enclosure do make a difference, obviously.

    However, these changes in the housing and stuff will have an impact in the frequency response, which one can also fine tune with an equalizer.

    As far as experiments with ears and stuff, I would start another thread to keep things organized.
     
  2. Serious

    Serious Inquisitive Frequency Response Plot

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    I just remembered something. Some of you may know that I used to have the HE60 pads on my HD600s. Well, I put those away again for FR reasons (too recessed around 1kHz, 3-4kHz too forward). When I put the old stock pads back on for the first time, it sounded like shit. I just found that measurement:
    L HD600 Pads.png
    (This one is without the in-ear compensation, but with the mic compensation.)
    It still doesn't look quite as bad as @Hekeli's measurement, but I can tell you this configuration really didn't sound good. I only have one channel at the moment, but what I did then was to try different types of felt under the pads to make them a little thicker and for some extra absorption.
    Interpretation of the measurements is still subjective in the end. You have to know how the measurements correlate to what you hear and which aspects of sound reproduction the measurements don't capture. You'd also have to guess which part of the measurements is just an artifact. Sometimes you measure resonances that you don't hear, or sometimes resonances sound worse than measured. Sometimes the FR looks very different from how it sounds. It all comes down to your own interpretation.
    Personally I like how the modded HD800 sounds, but I don't care much for the stock HD800. Modded HD800 measures pretty good IMO. Complete lack of resonances across the audio-band (and almost one octave above) with great treble extension and good enough bass extension. In this sense a real full-range minimum-phase system, something that's impossible with speakers. The only dynamic driver headphone that I'm aware of that does this. (Orthos tend to have ortho-walls which are weird and stats tend to have tiny ridges.) Distortion is very low throughout the whole range, but D3 rises once the excursion reaches a certain point. This is what you see in Tyll's measurements. I actually prefer low levels of D3 to D2, but that's just personal preference. Distortion through the midrange and treble is very low.
    Pitfalls may be bass extension and bass distortion. My listening volumes tend to be not high enough for the bass distortion to matter to me, but better bass extension would be nice.
    Objectively there's a lot to like about the HD800, but stock it also has a nasty bright frequency response, along with enclosure ringing. Those are very serious objective issues.

    It's entirely subjective to say which headphones are better objectively. Do you absolutely need flat bass extension and low bass distortion? Get an ortho. Do you want a great tonal balance? Get the HD6X0. Most stats, even the old one have great measurements. The ESP950 measures great.

    I agree. Do what you like, though. My ear seems to consistently measure with 5-10db less 6kHz than in-ear measurements I've taken from other people (and those that I've seen).

    I've thought about this some more. If the HD800 driver has a 82db sensitivity at 2.83Vrms at 1m, that would put its efficiency at around 97.7db/1W/1m, right? That's pretty high. On the other hand I read that making the voice coil thinner, but with more turns increases the efficiency, so it might not be that impressive relatively speaking.

    82db might work in a very inefficient, small bookshelf speaker with good bass extension that needs two Vidars to power it. The Ragnarok would probably not like such a speaker. I also like a slight downwards slope for nearfield listening (because of less room interaction), so you could probably pair it with an 85db efficient woofer.
     
    Last edited: Nov 23, 2016
  3. Serious

    Serious Inquisitive Frequency Response Plot

    Pyrate BWC MZR
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    BTW: I tried the small Comply T400 tips and two other silicone tips for my microphone. It all makes a difference, so try a couple different things and pick what you think is best when you decide to do your own in-ear measurements. I didn't bother to take multiple measurements for accuracy and consistency, but I'm pretty sure the results wouldn't have changed a ton. In the end I preferred the grey silicone tips I was already using. It's possible that I already compared them before and ended up ditching the nice looking black ones for the grey ones, which I feel are more accurate. The Comply tips seemed to smooth the resonances in the treble. I can hear a slight resonance around 7.3kHz when listening to sweeps (I can hear the same resonance with the HD600 btw). There's a steep notch centered around 8kHz on all of the measurements, which is a natural ear resonance. With the grey tips there was a tiny bump before the dip that was gone with the Comply tips. The pair of clear silicone tips that I had lying around had huge resonances here. In the end I'm still not entirely sure how accurate my results are. Take this with a grain of salt. It's possible that they could be much closer if I was super careful to make them all look similar, but I guess the tendencies would still stay the same. It wasn't easy to get the microphone into the Comply tips.
    I will still attach a picture of the FR of the 4 tips. This is without my in-ear measurement compensation. I don't hear the peak at about 5kHz when listening to sweeps.
     

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  4. randomg

    randomg New

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    Given all the discussion about what's actually correct, I wrote an email to a high end speaker shop asking if I could stop by and get some measurements. Hopefully they'll respond and I can get an idea of what I measure with these in ear mics in my own ears listening to a speaker setup much closer to ideal than what I have at home. If they say yes, I'll look into getting a friend to come along so I can get two sets of measurements.
     
  5. Grattle

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    Maybe this is foolish, but wouldn't the most accurate measurement of headphone fidelity at its liwest level be to actually measure the movement of the driver vs the input sound wave?

    We use lasers to measure distance, speed, and even temperature. Why not frequency and cone displacement? It seems like a logical starting point. Surely in the year 2017, this is possible.
     
  6. ultrabike

    ultrabike Measurbator - Admin

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    I have found that as far as frequency response is concerned, different levels yields almost the same result unless the level is so high that the headphone is about to give the ghost.

    IMO, laser cone displacement is not the best way to measure headphone fidelity, because while cone displacement is related to SPL, it is SPL itself what we hear. It is SPL what we measure.
     
  7. Grattle

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    But wouldn't the actual frequency of the cone vs the expected freq be valuable?
     
  8. Thad E Ginathom

    Thad E Ginathom Friend

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    Yes, I'm afraid it is. If the frequency with which the driver flaps around was the only thing that mattered, then anyone could make speaker cabinets of any dimensions/material, and all headphones would need to be is something that holds the driver near an ear.

    In fact, wouldn't all such devices sound the same?

    High-tech ideas are nice, but I don't think this one works.

    Maybe there is something in assessing vibration from different components/places? Like... maybe... bits that ideally would not be vibrating at all?
     
  9. ultrabike

    ultrabike Measurbator - Admin

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    I think it would be when designing a headphone. I think with speakers one looks at that among other things to figure out the dimension of the cabinet. But once the speaker is fully designed, I think SPL measurements are more telling.
     

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