HD800 Screwmount Mod

Discussion in 'Modifications and Tweaks' started by Royaume, Jan 31, 2020.

  1. Royaume

    Royaume Rando

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    *Please do not blame me or others on this site for any damage done to headphones*
    *You should not need other resources if you have an HD800. Instructions are clear*
    *This post will be kept updated in case of future additions to the mod. Comments start with #2*

    --To disassemble:
    Remove pads and dust covers
    Remove outer plastic silver ring from cup
    Remove T8 hinge screws from hinge
    --Reassemble in reverse order
    --Avoid letting loose screws near driver because it is magnetic


    **********SCREWMOUNT MOD**********​

    Reasoning:
    The Screwmount mod provides an alternative way to mount the HD800 driver. The StefanAudioArt mod also does this, but I have never seen the mod. It is proprietary, expensive, and incurs a possibly long wait. This method of mounting allows for the removal of the dreaded metal ring. Until now, this has been a puzzle. The driver is very securely mounted, pinched by the four Hex grub screws cushioned by small neoprene rubber "cushions".

    *These mod is reversible: If you are careful only screw threads will be left on inside of mounting holes*

    Required:
    Torx T6 screwdriver
    Torx T8 screwdriver
    Hex screwdriver/Alan key
    Hex socket grub screws, M4 (diameter 4mm), length 6mm
    1mm neoprene rubber sheet
    craft knife/Stanley blade
    cutting board

    Procedure:
    1) Disassemble.
    2) Remove 4 mounting screws from metal ring. Remove metal ring.
    3) Remove silver plastic mounting ring and black grill from outside of cup.
    (This can be done by lifting driver with a fingernail and pushing on inside of black grill with screwdriver)
    4) Cut some small pieces of the neoprene sheet to squeeze into the small gaps between the Hex grub screws and the driver. The gap is ~4mm deep and has angled edges so this may require some experimentation.
    [​IMG]

    5) Now comes the tricky part: We will pass the Hex grub screws through the mounting holes (now empty). Screw in Hex grub screws halfway only! This will make next step easier.
    6) Insert neoprene "cushions" and replace original metal ring to hold them in place. Squeezing as tightly as possible, screw in the Hex grub screws the rest of the way. Stop when the head of the screw is exactly flush with the black basket frame. Trust me, this is the perfect depth. Note: the holes have a lip on the inside which touches the foam ring. If you screw too far you will stretch/warp this plastic lip.
    HD800 (disassembled)(Screwmount)(cup interior)
    [​IMG]

    HD800 (disassembled)(Screwmount)(cup exterior)
    [​IMG]

    Leftovers:
    metal ring with spongy foam ring
    silver plastic mounting ring
    8x Torx T6 mounting screws
    black grill



    **********BIG COIN MOD(?)**********​

    Reasoning:
    The "dustcover vs no dustcover" debate is as old as the HD800 itself. When I first received her, I compared for myself and was dissatisfied either way. I immediately (after just an hour of deliberation) did this mod and haven't looked back . :headbang:I'll leave it to others to post impressions since it's a long time since I compared. My feelings toward the change in sound at the time (May 2019) were entirely positive.
    I did this before I knew about the HD650 coin mod. I'm open to suggetions for other names too.

    Required:
    paper
    pencil
    pair of compii
    ruler
    scissors
    craft knife/Stanley blade
    cutting board

    Procedure:
    1) Remove pads and dust cover.
    2) using compii, ruler, paper and scissors, mark and cut a circle of diameter 56mm.
    3) trace outline of paper circle onto \exact centre of dust cover.
    4) place dust cover on chopping board and cut out the outline with knife.
    //Perhaps use a lighter to tidy edges? Haven't tried.
    5) Replace dustcovers and then replace pads. If you have already done the Screwmount mod, then the dustcover should tuck nicely around the driver.

    HD800 (Screwmount)(BigCoin)(cup interior)
    [​IMG]

    Leftovers:
    2x circular dustcover cutouts


    [​IMG]
    So much more beautiful!
     
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    Last edited: Jan 31, 2020
  2. Royaume

    Royaume Rando

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    Hi all,
    First of all I want to stress that I couldn't have done this by myself. The ideas for this mod are building on the work of many other modders, and I believe we will continue to find better ways to improve the HD800. I want to open by thanking:
    @purr1n for dismantling and measuring the effects of the hd800 assembly,
    @Bill-P for putting it back together again and developing his own mod,
    @johnjen for his extensive experimentation with damping the ring,
    @Maxx134 for his many mods and experiments,
    @ThePianoMan for comments on Maxx134 thread,
    @Serious for measurements and comments,
    @Besnia for comments and explanation.


    There have been many others who have contributed greatly to my understanding of the HD800 and my enjoyment of music. I will add them to this list when I remember.

    I have listened to the Big Coin modded and hardwired HD800 for 9 months.
    I was finally was brave enough to do the Screwmount mod (planning for months) just a few days ago. Since then I have listened to the majority of my music collection! I have heard a definite improvement across the entire treble region. The timbre of many instruments is less artificial, more natural. I notice myself often anticipation a particular sound, only to be pleasantly surprised by a more liquid and natural sound than I expect.
    Note that I have not felt the need for a SuperDupont resonator! My FR certificate looks quite different from a typical HD800:
    mine
    [​IMG]
    vs
    [​IMG]
    I might be blessed with the goldilocks headphone!
    Subjectively, I hear a gentle downward slope from 200Hz to 100Hz, rolling off harder below that. 50Hz and 40Hz are still very reasonable in level. FR is very even the whole way up from 200Hz to 2kHz. No 4kHz suckout!! Instead I hear a broad hump centred at 5 kHz. Immediately after 7kHz there is a massive suckout centred at 8kHz. It recovers a little less suddenly, by 10kHz. 10kHz to 15kHz is even, and roughly in line with 1kHz. Overall it is still a slightly bright headphone and I will address the broad 5kHz hump, 8kHz suckout and decreased level at 100Hz and below with future mods.
    Sadly I have no measurement rig, and cannot measure the impact of these mods. I have kept them reasonably simple and replicable, so others should be able to test their effects.

    IF ANYONE HAS A MEASURING RIG AND HD800, PLEASE MEASURE EFFECTS OF THIS MOD (CSD)
     
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    Last edited: Jan 31, 2020
  3. Walderstorn

    Walderstorn Friend

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    Excuse me but i am confused, you open a topic about a mod and you have absolutely nothing about its results?! At least put some pictures of what you did, comments about the setup, etc...
     
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  4. Royaume

    Royaume Rando

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    I'm doing that right now. Please give me a chance. Btw, how do I get image links working?
     
  5. Royaume

    Royaume Rando

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    Ok, I figured it out
     
  6. allegro

    allegro Friend

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    Upload the images to imgur.com or other free hosting service then use the link ending in .jpg
     
  7. Royaume

    Royaume Rando

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    I want to share some of the story of this mod, and the thought that went into it.
    When I first dismantled and hardwired this headphone I spent at least a day examining and measuring each part. I spent countless hours shining light into it's darkest crevices and thinking about how exactly each part couples with the others. I noticed something that might be important:
    The driver is actually isolated completely from the rest of the assembly. it is damped from behind by a soft sorbothane/rubber ring, and in front by the spongy closed-cell foam underneath the metal ring. You will notice that every precaution has been taken to ensure that the driver unit does not touch plastic "arms" for the mounting screws. That is why there is a gap left where I put the neoprene "cushions". Even the "arm" which extends from one side of the driver toward the hinge is isolated from the rest of the assembly by a thick, soft, rubbery glue.
    @johnjen has experimented with replacing the spongy foam material.
    When I ordered the Hex grub screws, I thought they would grab the driver directly, and I was curious to try this and observe the results of directly coupling the driver to the basket/cup. However, there was a gap left. I quickly realised that I could take advantage of this and cut the cushions.
    If you find that the driver is pinched too tightly or not tight enough, feel free to experiment with the thickness of material or the type of material used to make the cushions. I have not tried anything else yet and any contribution is very welcome.
    Currently my driver is held very snug. It's a perfect fit, just like the screws I used.
     
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  8. Bill-P

    Bill-P Level 42 Mad Wizard

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    I think I did try something like this a while back and measured it. Will try to dig in my hard drives to see if I saved the results somewhere.

    Let's just say... it's interesting, but I think shelf-liner has a bigger effect overall on FR versus the stock cover thing. At least taking the middle piece away goes a long way into helping HD800 with its diffused sound.

    Also, replacing the aluminum ring that's used to affix the driver also has quite an effect. I haven't dialed in the right shape for 3D printing yet (still experimenting with it), but I think that's where the next frontier is.

    Putting a round piece of foam on the bottom of the middle hole instead of SuperDupont resonator also does help quite a bit with CSD in case you're interested.

    Let's just say... there is still quite a lot that can be done to HD800, I think. The drivers are very capable, but how Sennheiser is using them seems to be too heavily influenced by earlier decisions to emphasize the treble range.
     
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  9. Royaume

    Royaume Rando

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    Hi Bill-P!
    Thanks for your response and all your input. I knew there was someone important I forgot to thank! I am going to add links to each of the threads. I'll add yours too.

    If you can find the measurements of a similar mod that would be amazing.

    Yes, my goal in replacing the ring was not to change FR, I simply wanted to get rid of the ring, though I will try to alter FR with future mods. I will certainly try what you suggest, blocking the centre-hole with foam, and I'll read over your thread again.
    Ahhh, very interesting! It didnt even occur to me that I might replace it with another material. Now that you suggest this, I might try paper-folding one since I dont have a 3d printer. As a student I cant even afford a good amp nor dac, let alone a measurement rig and 3d printer:p

    What did you mean by this? I think we may need a "HD800 glossary of terms" thread! Its very difficult to think of names for each part that everyone will understand. I tried to be very clear above.

    I'm so happy to be corresponding with you, as I really came to admire your work during the months that I lurked here :bow:
     
    Last edited: Feb 2, 2020
  10. Bill-P

    Bill-P Level 42 Mad Wizard

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    Oh no, you did include me! That's how I learned of this thread. I don't check SBAF very often these days, so it's pretty easy for me to miss things. But I do read and study what other folks have done. It's not like I know everything... and there are indeed interesting things that I haven't thought of trying yet when I read folks' threads. For instance, in this one, I learned that I could attach the stock dust cover... on top of the metal ring! The last time I did it, I used the metal ring to hold the cover in place. Now that I think about it... I'm not sure if doing it your way may make more of a difference... or not. I'll have to find the stock dust covers and try this, then measure and report back.

    You can actually build an el cheapo measurement rig with $30 mic, and the cheapest 3D printer I know (and one that I use) is Elegoo Mars. You don't have to go broke trying to obtain these tools.

    I find anything on top of HD800/S drivers cause the sound to become very diffused and blurry... as opposed to just bare drivers. Granted, the surroundings gotta be covered or else bass extension goes right out of the window. It's a balancing act, I think. There's more to be done if you're willing to get closer to the driver... such as putting a circular piece of foam in the middle hole, like I suggested.

    Beyond that, I think you can reference the SBAF mod for what shelf liner to use and what shape to cut it in.

    I am unworthy of such praise. Honestly! I used to be a student myself not too long ago, and a lot of my "work" per se actually stemmed from me having way too much free time back then. Now that I hold a job and everything, I've had less time to experiment, but I'm still very curious and passionate about the hobby.
     
  11. Royaume

    Royaume Rando

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    Oh crap, lol!
    Thanks for the tips on measurement rigs and printers, I may well make a measurement rig! However, this would be a terrible distraction from my final year studies. It may have to wait some months.
    About the shelf liner, I am hesitant to imitate mods developed with the goal of altering FR, since I am quite sensitive to sibilance, but hear no problem with my unit, as an example. I should still try the Superdupont resonator and rugliner mods, even if only out of academic interest. I am already very happy with the timbral improvement since removing the metal ring. I cant wait to see what will happen with changes to pads, the centre hole, dynamat extreme, and earcup inserts.
     
  12. Maxx134

    Maxx134 Dunning–Kruger effect poster boy

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    That was excellent work to have unit secured with no grill.
    :)

    Suckouts are usually a Resonance thing.
    Typical suckout in hd800 was there so you may have shifted it when you tightened unit to frame.

    The hump is the climb from the 4k suckout that I assume you mitigated but still part of it.

    This alteration can be ripple effect of frequency dips change.

    Good work, I believe that can be address with optimizing your mod.
    Your using pressure to the existing rubber bottom which is acting like what sorbothane is intended for.
    This is the other route to choose instead of my dynamat.
    Choosing compression with sorbothane instead of dynamat.

    So completing, what I would call, your compression mod (of using those screws) with a sorbothane ring in place the metal, would "sandwich" the driver as intended.
    You don't have the top, only the bottom now has a compressed rubber.

    No prob check out the measurement rig thread here and at least you can download the REW program to use its its sound generator to listen.
    Anything is better than nothing and most measurement setups at least conform in the midrange frequencies.

    That is great you pointed that out.
    Very important to make note how the driver needs vibration absorbtion, either thru sorbothane with compression (stock setup) or by my method of dynamat extreme.
    Both do the job of vibration control, so it won't get amplified into the metal basket.

    That was an excellent job!

    Yes it has a bigger effect, but wether positive is up to the user.
    I consider this frequency absorbtion alteration to be post driver, or after the driver makes its sound.
    Personally I gave up on this route because it reduces the inner volume of space, and always (for me) diminishes the soundstage.

    I agree this is the other road to alter the HD800.
    But plastic introduces Resonance and the intended design was for compression using that metal ring.
    Thanks to this thread for pointing out the bottom rubber/sorbothane layer, which, by its very use, implies the intention of compression.
    Sorbothane does not work any other way but compression or expansion.
    It use implies the need for compression, which aludes to the ideal solution being a sorbothane ring on top to sandwich the driver.

    Maybe even longer screws to apply a sorbothane ring, and also put back the metal ring.
    It is NOT the bad thing most may believe, but instead needed to apply the even pressure for the underlying sorbothane/rubber under the driver.

    I tried this and also other things like elimination the center totally..
    IMG_20200317_165901__01.jpg
    CSD can be cleaned up, as you describe, but the resultant sound was not optimal.
    Covering the hole at rear created an effect of closing in the sound, similar to a closed headphone.

    And opening the hole totally killed all the bass.

    I believe the two forms of vibration control that can optimally be placed around the driver, are either dynamat method, or sorbothane method which works differently than dynamat, by being either under pressure or expansion. In this case it is obviously compresson.

    It makes sense now, how the bottom sorbothane/rubber gasket is being used under the driver.

    The question of which is more effective, dynamat or sorbothane, is a really the next step.
    We know in stock form, it is woefully ineffective at combatting the ringing, and my usage of dynamat I shown in my measurements to actually work.

    But I now believe that stock form was incomplete due to lack of sorbothane between the driver and metal ring...
    So that needs to be looked into, for an alternative solution instead of dynamat.

    Some longer screws and a ring of sorbothane under the metal is what can be a real solution here..(!)
    :)

    Although I am not using the metal ring any longer, I am of the firm opinion that it is not detrimental to the tonality of the sound at all.
    I use nothing to cover my soft metal on my latest mod.
    IMG_20200227_204339.jpg
    And the fatigue I have noticed in past was instead actually due to the rear grill, so either removal or dampening there (I applied a thin shelf liner) helps.
    :)
     
    Last edited: Mar 18, 2020
  13. Royaume

    Royaume Rando

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    Gee thanks!
    So sorry for the late response. For some reason I wasn't alerted and so I didn't see this until today. I am delighted that you and Bill-P have now seen the work I did. I was the two of you and JohnJen who inspired me to do this.

    Oh fascinating, I remember you really didn't want to remove the rear grill. Personally, I just didn't think it was necessary so I yoinked it out and never looked back! :p I didn't even bother thinking about it. I definitely heard a big timbral improvement, but since I did the driver remounting at the same time, I never knew which change contributed more to the overall improvements. (or maybe I did some listening tests... I don't remember)

    Anyway, thanks for all the work you originally shared as it helped me a lot. :bow:
    I am not finished with these headphones. I had to put my modding to one side for the past couple of years, but maybe I will get to finish the project I started some time soon.
     
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