HIFIMAN Headphone Compendium

Discussion in 'Headphone Measurements' started by purr1n, Mar 24, 2016.

  1. Thujone

    Thujone Friend

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    @E_Schaaf - do you have documentation of your HE-4 mods? I got wind of them in another thread and, being a long time HE-4 owner, was curious what you came up with.

    Mine have been gathering dust over the years but quarantine has brought me back to headphones. Unfortunately, I'm more sensitive than ever to the sibilance on these. Any chance anyone has had luck mitigating this? I once played around with a passive resistance filter (thanks to advice from Solderdude) which helped reduce treble intensity:

    [​IMG]

    Blue: stock
    Red: filter to bump up treble surrounding the 8k peak in an attempt to flatten the response
    Purple: filter to drop treble

    Note: the 200Hz - 1kHz sawtooth region is the result of removing the star felt on the back of the driver (the only other mod on these headphones). This was much flatter with the felt still present, though I don't have that measurement on-hand anymore.
     
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  2. E_Schaaf

    E_Schaaf MOT: Upscale Audio; recovering HFM addict

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    @Thujone - first of all, hi! I remember lurking and reading your posts way back when on Changstar and HF. Seems like you were inactive for a while, but it's good to meet you.

    HE4 is really difficult to work with, and no matter what you do, the distortion profile cannot be remedied. It's a tapey sounding headphone. Treble sounds 'lit' and crunchy. I like that about it, but I can see why others might be put off by it. Lots of color.

    My mods involve a 2-ply TP sandwich (I forget the brand and have tried dozens, this particular one I've settled on seems to damp dynamics the least but really great at reducing 6.5k and above), with a small cut of melamine and woven fabric (I have what I have and probably can't get more because honestly forgot where it came from, but it's the best for HE4 I've found) in between. And finally a layer of rug liner on top, and a melamine cut on the back above the stock star felt mostly used to protect against dust and particles since I have no grills. No star felt on the ear side, I forget how it came stock.

    Earside sandwich filling (not pictured is the second TP layer and rug liner) -

    [​IMG]

    Backside (the melamine layer is very thin) -

    [​IMG]

    Given the mods are asymmetrical, FR measurements are all over the place depending on positioning. I moved it around a bit this was more or less in-between ears all the way forward in the pads and ears all the way back. Measurements below are with EARS+SBAF comp -

    1. [​IMG]

    2.[​IMG]

    Don't mind the sub rolloff on the graph - sweep confirms dead flat below 100hz as expected for this planar phone. It's hot in my apartment today so lots of fans and AC running probably throw off the low end reading quite a bit. The pads do add a bit of midbass. Just need to add more double-stick tape to maintain optimal seal (I'm using ZMF Ori Lambskin non-perforated pads on these - the height of these makes measurements extra difficult to replicate).

    Pretty sure I have stock measurements on my work computer but won't be able to post those until shelter in place is over. You can see this thread for reference measurements with my same comp curve and coupler for the sake of comparison - https://www.superbestaudiofriends.o...easurement-dump-zmf-focal-audeze-extras.8087/
     
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  3. Thujone

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    Glad to meet you too! It's always exciting to find another HE-4 lover out there. The treble etch and overall distortion is definitely troublesome, but these are really dynamic headphones. Even the HE-6 and LCD2C have less punch. On top of that, the HE-4 is super light!

    Thanks so much for the pictures, you've given me some inspiration. I have never used melamine foam for anything but Mr. Clean Magic Erasers, but it looks promising as a dampening element. It looks like the back of your driver has the star felt intact, did you glue the melamine on top to keep it in place?

    I spent an embarrassing amount of time this morning googling toilet paper patterns to see if I could figure out what you used... ultimately I'm okay with some experimentation. I've also had great luck with using basic fabric in the past.

    Pads are... well, I'm going to figure that out last. Years ago the Audeze vegans were promising for the treble grain but less so for the dynamics. Regardless, this isn't a cheap thing to experiment with and I need to see if TP mods are going to save it or not. What pads does Luis put on the Code series headphones?
     
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  4. E_Schaaf

    E_Schaaf MOT: Upscale Audio; recovering HFM addict

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    I've had his modded HE6 and HE5LE and spent a good bit of time with some other friend's LFF modded HE5's too. Always the same pads and the mods are fairly straightforward too (though I'm hesitant to post publicly about it since he's worked to keep it fairly secretive). His pads are the same exact dimensions as these - https://www.brainwavzaudio.com/products/headphone-pad-angled

    Pretty sure he gets them batch from aliexpress - his pads aren't pairs either, one needs to be flipped upside-down when you stick it on.The leather feels slightly different, but FWIW I actually preferred the sonics of the HM5 over his, and the Ori pads over either at least on the HE4. LFF uses the plastic ring to maintain circular shape on the oval pads so they can stick on to the headphone via double stick tape.

    The key to melamine is to cut it as thin as possible - like just a mm or two. And not a complete covering either. It's also really great stuff for putting in cups on closed back headphones. The pic above of the front damping is flipped upside-down since I work on the headphones with the cups turned around. So the melamine is meant to be around where my ear canal is when I put the headphones on.

    I don't use any adhesive - the melamine sticks to the back just with friction (and the wires keep it in place), and my cuts for the front have enough overhang that screwing the plastic ring down simply holds everything in place. I'm scared to use adhesive given I undo and redo the mods a lot and never settle on one config (though the one above has been on there for maybe 4 months).
     
    Last edited: Apr 29, 2020
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  5. Biodegraded

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  6. E_Schaaf

    E_Schaaf MOT: Upscale Audio; recovering HFM addict

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    Makes sense, Upscale supplies toilet paper and office stuff from Costco. Thanks for that @Biodegraded !

    That stuff is really great for toning treble on TH900 too without acoustically impeding the frontwave excursion - this headphone's very sensitive to that and will sound overdamped with even 1-ply of some thicker TPs, which (believe it or not) can measurably reduce both deep bass and treble while increasing midrange distortion (yuck).

    Not the case with Kirkland Sig 2-ply, even folded. You can wet and air dry it for an even lighter effect.

    This conversation is hilarious.
     
  7. Biodegraded

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    Have you tried Kleenex or similar tissue? That's more subtle still, I found one ply to have less effect on the treble than one ply of the Costco (which itself had more effect than 2 others I tried, both Purex IIRC) when AKG modding. All papers also had a subtle effect on the midrange FR (second graph).

    My distortion results are always crappy, but after what you've said here I'll go back and check them to see if there's anything...
     
  8. Thujone

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    Damn. You're good.
     
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  9. AstralStorm

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    I had to fix a broken internal driver connection cable on my HE-6SE. Those tiny silver wires are fragile and poorly soldered. I've also decided to more tightly screw the driver assembly into the ear cups. Additionally uncovered an additional high quality felt pad under the big metal nut, which is likely responsible for some sonic improvement these have over original HE-6.
    Tightening the screws further reduced resonance and the remaining "sharp" quality to the sound.

    Seems Hifiman should either invest in some better electric screwdrivers, and/or feed their workers more meat.
    I screw my screws well.

    I'll attempt some advanced composite custom pads, since it seems to be the last avenue to improve on these. (Also check the Dekoni pads, but I suspect they won't be a great match.)
     
    Last edited: Jun 30, 2020
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