Bill's HD800 mod thread (final version)

Discussion in 'Modifications and Tweaks' started by Bill-P, Sep 27, 2015.

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  1. paranoidroid

    paranoidroid Friend

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    Interesting. Would be interesting to measure both headphones stock with the same ear pads. And then, the same headphone with both earpads.
     
  2. Bill-P

    Bill-P Level 42 Mad Wizard

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    Yeah...

    [​IMG]

    [​IMG]

    [​IMG]

    2dB of extra low bass is not subtle at all IMO. That should be audible. Also the highs are more rolled off on top based on the trend. Mids didn't change all that much, but perhaps slightly more linear.

    So pads alone make quite some difference. Driver differences didn't seem to account for much. Not even in CSD. My HD800 rings ever so slightly less (like 0.1ms less), but other than that, no difference. FR and CSD are so eerily similar with the same pad that I'd have to applaud Senn for the consistency in the drivers, but the pads... man, why did they switch to these fatter pads? The old ones are better IMO. More comfy and moar bass!
     
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  3. kapanak

    kapanak Canucklehead - Friend

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    Your measurement rig seems to resolve well until 10Khz, so that's great.

    Sennheiser's HD800 driver matching seems scary excellent given all other factors are constant.

    Would be interesting to start a new thread with this subject of variation (we had one on Changstar), and have all owners kf HD800 measure their pad dimensions and state their serial number. Pads always make a difference, and given how sensitive to change HD800 is, pads seem like a major factor (though almost mutually exclusive of metal ring, metal mesh mods, since those aim to tame the 6K treble glare).
     
  4. Bill-P

    Bill-P Level 42 Mad Wizard

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    Yeah. My last coupler was only reliable up to about 8KHz. I fiddled with reflections and surface area, and how much the mic is exposed, etc... and now it's somewhat more consistent up to about 10-12KHz or so. Still, anything above is volatile.

    Anyway, will start that new thread some time soon. I'd like to investigate this matter more.

    Luckily, CEE TEE does have another pair of older thinner ear pads around, which I'll seize. |\/|

    But more to the point, if CT's other pair of ear pads also exhibit this behavior, I think HD800 owners would benefit well from some 3rd-party pads and/or pad mods...
     
  5. George Mhmmm

    George Mhmmm Acquaintance

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    I'm too afraid to take my pads off in fear of breaking that plastic and not being able to put it back on. You should try just a layer of foam and maybe some felt or whatever you have at hand around the cup circumference.

    Curious to see what that would measure like.

    Edit: it's interesting to see the peak shift from dead center 6k with new thicker pads to 6.5k with older narrower pads. This is a pipe dream but maybe the pad design could shift the peak down into the 4K range and cancel out the dip observed there. Or shift the peak even higher into the 7 or 8k range.
     
    Last edited: Oct 22, 2015
  6. Tyll Hertsens

    Tyll Hertsens Grandpappy of the hobby - Special Friend

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    Let me know pif you want me to do measurements for you, Bill.
     
  7. audiofrk

    audiofrk Guest

    Did takato ever send you his hd700?
     
  8. Tyll Hertsens

    Tyll Hertsens Grandpappy of the hobby - Special Friend

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  9. Bill-P

    Bill-P Level 42 Mad Wizard

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    Thanks, Tyll! I'll send this off to you whenever I feel like it's good enough. For now, there are still so many things I have to learn about it.

    This is probably the most interesting project I've worked on in the audio world for sure. \/
     
  10. Bill-P

    Bill-P Level 42 Mad Wizard

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    Cuz I had some free time, and access to CEE TEE's HD800 again, I did some measurements again.

    Note that the driver matching between my and CEE TEE's HD800 is so very very very close that... barring anything to do with pads, they are practically identical. There really was no point in me in trying to measure a different pair of HD800 here. Maybe there were slight variations prior to CEE TEE's pair? I dunno, but my pair and his measure like... within 0.5dB of each other with the same pads, which is scary.

    Anyway, with that said, here are measurements of the 1.0 mod:

    [​IMG]

    And... there you go. 1KHz is raised accordingly, but the peak doesn't want to go away. I guess that's just how it is.

    Bonus, measurement of the on-going 1.5 mod:

    [​IMG]

    Like I said, the 1.5 mod is more for me, and those folks who really can't stand high treble output. I'm mostly okay with this now, but only if it could be smoother. Gonna try Sennheiser's HD800S style donut thingie soon-ish. If it does what I think it does, that may just be "it" for me.

    And as always, these are relative differences, and only on my measurement setup, so please take these with a grain of healthy salt.

    Oh, and fun fact: while the stock (w/o dust cover) and 1.0 measurements were done with CEE TEE's HD800, the 1.5 measurements were done with mine. Note how scary 20 - 1KHz matching is. Senn deserves some praises for just that alone. These are TWO different headphones.
     
  11. kirayamato

    kirayamato Friend

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    really interesting stuff keep up the updates
     
  12. Maxx134

    Maxx134 no one will touch his boy parts without $$$

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    Hey Bill-P,
    A big thanks for your contributions to ongoing modding!
    I would like to add two points to your work:

    1- the pads I have noticed flatten out over the years and seem to magnify the characteristics in the trebles, whether that be sweeter or harsher depends on your actual mod.

    This pad also had a cavity which I found benificial to insert material to bring back a flattened pad, which actually some like more(!).

    The one thing I forgot to try,
    And may be a major factor for bass improvement,
    Is to use a more dense, non-porous material, instead of stuffing with rug liner inside..

    I am thinking to stuff a more solid material closer to leather inside, which should help give more of a seal around ear for bass response..(!)

    Second idea
     
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  13. Maxx134

    Maxx134 no one will touch his boy parts without $$$

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    Ok second idea,
    which I have verified with fast switching ear trials over same driver:

    I have come to the conclusion ,
    and am comfortable certain,
    that the rear grill is introducing reflection back into the driver(!)

    This is very minute and the sonic trait is a harshness/fatigue in the treble area...

    You can verify by listening with it taken off and quicly place it over the rear of driver..
    Sorry I do not have the software/coupling mechanism to visually show this effect.

    Yet I do not recommend removal of this important protective grill, as the crazy SAA mod does.

    Instead I have found a solution of dispersion without damping or covering totally the grill.
    I am using a small circular piece of VERY thin black shelf liner, that I place inside the grill:
    [​IMG]
     
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  14. Bill-P

    Bill-P Level 42 Mad Wizard

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    I have modded my pads, of course, and this is by far the biggest factor in sound change compared to anything else. Rug liner doesn't have this much of an impact on sound.

    So yeah, I'd say... if you have any idea for pad mods, go for it!

    As for back damping... I don't like them in any way. Rug liner or not. I do try to kill some reflections in the back by lining the plastic parts with microfiber cloth pieces that are cut to shapes. This helps reduce ringing by a lot, but doesn't seem to reduce overall sound pressure level (read: the peaks stay). IMO, rug liners help drop the overall perceived level of treble by elevating all other regions, but doesn't help with ringing. But that could just be me.
     
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  15. Besnia

    Besnia Almost "Made"

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    Hi guys, kudos for all the effort you've invested. I really appreciate it, since I'm about to start modding a pair of HD800 here.

    I see the topic revolves mainly around the treble issue. I don't want to negative about this, but I don't think we can ever reach perfection in this area. Jaggy/edgey sounding treble is somewhat inherent to transducers with highly magnetized neodymium magnets. In order to effectively overcome the winding and exert control over the cone, they have to be highly magnetized. This is related to the poorer hysteresis properties of the neodymium magnets, compared to barium-ferrite and cobalt permanent magnets. To my ears the stronger the neo magnet, the better the transients become, but the trade off is the sound gets pretty edgy, like it's full of tension (just imagine an epic power struggle between the magnet and the coil). Pretty fatiguing to my ears. For example, on the other end of the spectrum are the high quality crystal-based cobalt magnets, which retrieve amazing details out of the recording w/o having to be so strong (in fact they can't be that strong). And they always sound silky smooth. We can play with damping and achieve some excellent results (i personally subject all my off-the-shelf HP & speakers to any mod my evil plotting mind can come up with), but the limiting factor will always be the properties of the driver motor.
     
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  16. TomNC

    TomNC Facebook Friend

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    Good information on the HD800's driver. Wait to see how the resonator remedies the treble problems and smoothes the highs. With the chamber damping mods, the primary goal seems to address the piercing 6K Hz peak. Even with the mods, the HD800 to my ears is still bright (>HE-6>HD650), but not worse than SONY CD3000 that I used to own.
     
  17. Bill-P

    Bill-P Level 42 Mad Wizard

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    Yeah, you're right. The "transient edge", as I call it, is just inherent to the driver. However, we can mitigate it at least to the point where it's not flaring up in all recordings, but only in some, and at very specific spots.

    The thing is... I know the 6KHz peak is not inherent to the HD800. I have heard a headphone that uses HD800 drivers that do not exhibit strong treble. In fact, here are some measurements:

    [​IMG]

    So... I agree, transients are all on the drivers. They are just fast, so they will sometimes cause a sharp sound to come out. But the treble? That's all on Sennheiser's tuning. They could have tuned this driver to be perfectly flat, but they opted not to, and instead went for this sound because their board of directors wanted it that way.

    If Sennheiser wanted to, I'm 100% sure they could have made this headphone perfectly flat already. They did engineer the driver close to perfection after all.

    And another thing: it is also possible to mitigate the treble peak to the point where it's no longer standing out:

    [​IMG]

    It's still peaky, but not entirely antagonizing, whereas at stock, it'd always make my ears ring after one song... any song.
     
  18. TheManko

    TheManko Rando

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    Regarding the earpads, they must only have gotten thicker recently. I have three sets of them, originals from 2010, and replacements from 2012 and 2014. I just measured them, and they're all identical to those older ones.
     
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  19. Bill-P

    Bill-P Level 42 Mad Wizard

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    Thanks for the info, Manko.

    I'm gonna have to contact Sennheiser one of these days to ask about them. I just don't really think my HD800 needs a new pair of ear pads right now.
     
  20. Maxx134

    Maxx134 no one will touch his boy parts without $$$

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    I have been comparing the hd800 to the Ether...
    While I have increased my bass,
    There is a trait that I find on the Ether that I am currently trying to capture...
    There is a sort of "body" to intrsuments.
    Not just on bass,
    For example even cymbal taps of drummer have more substance to the hits,
    Wherease the hd800 seems thinner, airy, ghost like...
    Details pop out, but dissapear so quick that it leaves a ghost like image,
    So not as much body to instrumments...
    Bass is soo defined, but at same time soo airy as to not feel satisfied even with levels that can shake your jaw...
    Its like a ghost, yet vocals are sooo good nothing beats it for me...
    So I am now frustrated that an Ether which does nothing spectacular, has all the ingredients to musicality,
    While my hd800 is missing a trait of solidity to complete it.
    Aside from this peak which I feel you have already solved enough to be acceptable.

    So I have been experimenting with the pads, but I am thinking it is the dam basket that is a double edged sword...
    It separates the driver from the pads...
    :(
     

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