Poor Man's FD01 (HSE A2000 modded)

Discussion in 'IEMs and Portable Gear' started by james444, Jan 25, 2019.

  1. james444

    james444 Mad IEM modding wizard level 99

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    The JVC FD01 with DIY-filters have earned a reputation for being some of the best IEMs for dynamic driver fans. This tutorial is for those who can't (or don't want to) afford the real thing. But it's also for those who love the FD01 and want a cheap beater IEM that sounds very similar to their JVCs.

    [​IMG]
    [​IMG]

    The HSE A2000 are budget IEMs that can be ordered from Amazon Japan and shipped via Amazon Global to more than 65 countries. They typically cost around $30-40 shipped, depending on destination country (which is roughly 1/10th of the JVC FD01).

    Gunmetal color: https://www.amazon.co.jp/gp/product/B07DHXJ5WF/
    Various other colors: https://www.amazon.co.jp/gp/product/B07DHXT9RR/

    These are well-made with aluminum housings, flexible cable and proper strain reliefs, but otherwise very basic IEMs. No in-line remote or mic, no case, just the IEMs and three pairs of smallish silicone tips. Large ears may need third party tips in order to get a secure seal.

    I haven't found much more info on these, other than the fact that they're Hi-Res certified, feature an 8mm graphene coated driver and are supposed to restore true sound.

    [​IMG]

    Well, let's take a look at what "true sound" means in this context... hmmm, not all that impressive imho:

    [​IMG]

    And sure enough, these sounded decidedly v-shaped and aggressive / sibilant out of the box. As far as I'm concerned, I don't care much for this kind of tuning, so it was either mod or trash, from my pov.


    Modding instructions:

    You'll need a 0.5" roll of micropore tape for this mod. If you can't get it locally, you can order it via ebay for little money:
    https://www.ebay.com/sch/i.html?_fr...acat=0&_odkw=3m+micropore+tape&LH_TitleDesc=0

    The other thing you'll need is the twist tie that comes with the IEMs (don't throw it away!). Strip off about one third of its insulation, than cut the bare wire off:

    [​IMG]

    With the remaining two thirds of the twist tie, you can make yourself a nice little chin slider:

    [​IMG]

    Then use the bare wire to remove the stock mesh. (This mesh has been bugging me for hours on end while trying to find a mod, cause it made micropore damping on top of it very unpredictable):

    [​IMG]

    Close up the nozzle with micropore tape, then use the wire to poke a single hole near the edge:

    [​IMG]

    Here are the frequency responses for different variants of front damping: stock, full micropore, one hole and two holes. For our purpose of emulating the FD01, I found a single hole to be the best choice.

    [​IMG]

    Now it gets a little tricky, because we have to bring down the bass. Unfortunately the A2000 don't have a front vent, so we need to create an air duct underneath the tips as a substitute.

    Wrap micropore tape tightly around the wire. For a proper duct underneath the stock tips, you'll need 10 windings of tape:

    [​IMG]

    Make sure that the result looks like this:

    [​IMG]

    Gently pull the micropore roll off the wire, cut it in half and press very firmly to flatten the parts to strips:

    [​IMG]

    Then place a strip alongside the nozzle, so that it protrudes at the front. Hold it carefully in place as you mount the silicone tip:

    [​IMG]

    Check the result - it should look like this from the front side:

    [​IMG]

    Measurement time! Blue is the FR without air duct, green is the new response. You can see that the duct not only brings down the bass, but also has a further smoothing effect on treble:

    [​IMG]

    Finally, let's compare the result to the modded JVCs (orange). Lo and behold, a Poor Man's FD01 is born!

    [​IMG]


    Disclaimer: A properly modded HSE A2000 is able to closely emulate the FD01 and sound stunningly detailed without treble sharpness (a feat you won't easily find on budget IEMs). Its timbre is on par with the JVC's. However, the FD01 are still a bit better to my ears in overall refinement and transparency, which is hardly surprising given the difference in price.

    But most importantly, the "air duct mod" is very much dependant on tips, so if you prefer third party tips, you'll have to figure out the number of tape windings (for a neutral bass response) by yourself. Moreover, "burn in" can be real with this mod, particularly if you didn't press hard enough to flatten the micropore strips. So, if you notice the bass becoming stronger after several hours of use, it just means that the strips become flattened and less air can escape through the duct. Eventually they'll settle though, and bass levels will remain constant.

    On the plus side, you can achieve pretty much any bass level you like with this technique. Want a little more oomph, just use 8 or 9 windings instead of 10. Too much bass? Try 11 or 12 windings for a slight increase in leakage and decrease in bass. Just trust your ears to find out which mod signature suits you best. :)
     
    Last edited: Jan 25, 2019
  2. Merrick

    Merrick A lidless ear

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    I admire your dedication to getting the best sound possible out of DD IEMs regardless of price. For me, the JVC is tops but its awesome that you continue seeking out other great untapped IEMs for people to try. Cheers!
     
  3. Taverius

    Taverius Smells like sausages

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    Worth the upgrade from micropore'd A&D D6s?
     
  4. Brause

    Brause Acquaintance

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    Thanks @james444: Most importantly for us, you found a universal way to reduce bass without poking or drilling (some crazy Canucks have murdered quite a few earphones in cold blood before).

    I'll try this mod on the overly bassy but otherwise very good sounding VJJB K4S while my HSE unit is shipping from Japan.

    UPDATE: I did 12 windings on the VJJB - bass is overly light now (still waiting for the effects of the "burn-in/squeeze in"). The point: the air venting works even for hard cases like this one.

    [​IMG]
     
    Last edited: Jan 25, 2019
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  5. james444

    james444 Mad IEM modding wizard level 99

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    Hard to tell. I just A/B'd them and the micropore'd A&D D6 are very good, too. The PMFD (Poor Man's FD01 ;-) have better extension at both ends, a tad more sub-bass and more air on top. But the difference sounds less significant than it looks in a graph comparison (green = PMFD, brown = A&D D6):

    [​IMG]
     
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  6. zerodeefex

    zerodeefex Grumpiest admin

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    welp, ordered a purple pair (green and purple were cheapest) for $25 shipped. Given how good the modded FD01 was, I can't wait to see where this lands.
     
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  7. Friday

    Friday Friend

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    How are these for commuting? I'm assuming that isolation suffers with the bass "vent" mod
     
  8. james444

    james444 Mad IEM modding wizard level 99

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    If you don't want to wait for the effects of the "burn-in/squeeze in", you can cautiously use pliers or a small hammer to help flatten the strip.

    The majority of DD IEMs are front-vented, and isolation with the "vent" mod is pretty much on the same level. To mod these for commuting, I'd probably use just 8 windings of micropore or less, to retain a moderate bass lift. Which in turn means, that the air duct will be very narrow and hardly affect isolation.

    If you commute in very noisy surroundings and need high isolation, vented DDs with barrel-shaped housings are definitely not a good choice though.
     
    Last edited: Jan 26, 2019
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  9. Taverius

    Taverius Smells like sausages

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    Gunmetal Inc. It always amuses me that a single roll of micropore is like, 1 euro free shipping from China, but like 8 euro with 5 euro shipping from Europe.
     
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  10. Brause

    Brause Acquaintance

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    I did some rolling, stripping, clipping, and squeezing (good to have a leatherman tool), played with the number of windings, wire thickness, and tape thicknesses...

    My observations: whatever I did, I appeared to remove too much bass...which is good as it shows that the air-vent mod works. My tubes were too thick.

    I finally hit is with the iBasso IT01: a single DD bass monster. Adding these "tubes" did not only rectify the bass but also added clarity and three-dimensionality. The vocals are now intimate and forward.

    What I am wondering about @james444: does the air-vent mod affect the treble or is that my imagination? Removing bass my create the wrong perception of having created piercing treble.

    Could not measure it as I use tips for listening that are too large for the coupler...which would result in an underestimate of the bass.

    The other thing: have you tried venting by poking strategic holes in the rubber tips (e.g. at the transition of the inner and outer tubes)?

    The graphic below is only schematic.

    [​IMG]
     
    Last edited: Jan 26, 2019
  11. james444

    james444 Mad IEM modding wizard level 99

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    Reducing the bass level does of course affect treble perception, since we hear frequencies relative to each other. A treble spike gone unnoticed on a bassy IEM may suddenly stand out like a sore thumb after attenuation of the bass range. The easiest way to figure out whether your piercing treble is real or an unwanted byproduct of the vent mod, would be to try the same amount of bass attenuation by equalizer and compare the resulting sound signatures.

    That said, I'd appreciate it if we kept this thread on topic of the modded HSE A2000 and try to keep digressions to a minimum. Please try to see things from a reader's perspective, who may find all kinds of graphs here that have nothing to do with the A2000. Needless to say, I'd be happy to discuss IEM modding techniques in a dedicated thread though.
     
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  12. james444

    james444 Mad IEM modding wizard level 99

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    @Brause: Great idea to put off-topic graphs in spoiler tags, thanks! :)

    As for your last question:
    Yes, I've done experiments with that too. However, there are several issues with it. To begin with, it's not reversible. Then there's the fact that different sizes of the same tip often differ in thickness of silicone (and rigidity) at the transition of inner and outer tubes. Moreover, if you insert tips into different sized and angled ear canals, they may warp and bend in various ways, which may alter the shape of that vent hole and result in varying air-flow for different ears.

    In short: consistency is a huge problem with that approach. It may work adequately for your own requirements, but if you publish a tutorial for the community, you need to make sure that everybody has a chance to get reasonably similar results. No doubt, the micropore-strip / air-duct method also involves some variability. But it's reversible and ime more consistent than poking holes in tips.
     
    Last edited: Jan 27, 2019
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  13. james444

    james444 Mad IEM modding wizard level 99

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    Here's how to check channel balance of your air-duct mod: Use a tone generator to verify that bass is centered:

    http://www.szynalski.com/tone-generator/

    If you hear bass off-center towards one side, it means that this side has less airflow than the other and you'll need to redo the mod.

    Repeat the test after several hours of use to make sure the mod has settled and remains constant.
     
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  14. fraggler

    fraggler A Happy & Busy Life

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    Thanks for finding and sharing these! I have a set on the way from Amazon.jp and some micropore tape on the way from Amazon.com. I tend to need bigger tips than stock so was wondering what size bore I would need. Is it Campfire sized?
     
  15. james444

    james444 Mad IEM modding wizard level 99

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    Nozzle diameter is a little more than 5 millimeter. I don't have CA tips, but pretty much all my wide-bore tips fit the A2000.
     
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  16. gixxerwimp

    gixxerwimp Professional tricycle rider

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    I got these in 4 days from Jamazon, finally an advantage to living in Asia, far from most sbaf activity.

    I found them to be still too bright with 1 layer of micropore. Adding a partial 2nd layer helped, but stifled the mids. So I tried adding the original FD-01 filter, but used the inner layer of a "surgical" mask* as I'm at my in-law's for Chinese New Year and forgot to bring an alcohol swab. I think the material is fairly close in thickness and texture. My target was to have 2 layers inside the nozzle and a 2cm length was a bit more than that.
    20190203_174139.jpg

    Cbf'd to trim it so I put the micropore on (including bass vent) and the tonal balance was about right for me with no hole. Still a touch of sibilance, but not bad for $25 and a couple of hours of fiddling around.

    *They're commonly worn in Asia to protect from pollution and airborne germs.
     
    Last edited: Feb 3, 2019
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  17. james444

    james444 Mad IEM modding wizard level 99

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    I take it you didn't mod the bass? The air-duct mod further smooths out treble, as shown in graph #3.
     
  18. gixxerwimp

    gixxerwimp Professional tricycle rider

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    I did. Followed your full instructions initially.
    I thought it was implied so I didn't mention it at the beginning. Maybe there's some variation and my pair are brighter.

    If they could work these mods into the production version, they'd have a really good budget iem.
     
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  19. james444

    james444 Mad IEM modding wizard level 99

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    That's possible, of course. The two units I've got so far have been surprisingly consistent though.

    Also possible are different ear canal resonances. With a sound signature like that, it only takes a few dBs more to cross the line.
     
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  20. Brause

    Brause Acquaintance

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    Fast shipping from Japan to Canada. OOTB it has a good, dry, punchy bass and excellent clarity and sense of space, but it is overly bright, borderline sibilant, and the treble is outright piercing. I had to tape my eardrums off with micropore and also stuffed some swabs down my ear canals. The rubber (tips) come in sizes M, S, and XS...everything is smaller in Japan.

    FR below is unmodded. Curve is raw.

    [​IMG]
     
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