HD800 Resonator Tweaks and Experiments a la HD800S

Discussion in 'Modifications and Tweaks' started by purr1n, Oct 25, 2015.

  1. purr1n

    purr1n Finding his inner redneck

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    It's just open cell foam. The stuff you find in shipping boxes. I cut up small pieces and shoved them in the straws.
     
  2. Halaudio

    Halaudio Rando

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  3. Stapsy

    Stapsy Friend

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    Thanks Marv, I am giving this a try right now.

    First impressions are that it is an improvement. It sounds similar to Anax 2.0 but without losing the air. I need more time to go back and forth to see how much difference it makes and refine the pieces a little

    For anyone who wants to try I have found the biggest straw from Starbucks to be the best fit with a three straw setup.

    I have it set up with the rug liner from the Anax 2.0 in a new design I am working on trying to get a more consistent fit. I can post the template if anyone wants to try it and give me feedback.
     
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  4. drez

    drez Acquaintance

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    This is really interesting project - in my own modified HD 800 there is still some brightness in certain frequency regions which stands out especially in acoustic instruments which traverse the peaky regions. It's very interesting that the center of the driver vents straight out - I never thought about this before - this is very obvious place to locate dampening however this would likely affect the "open" sound of the HD 800. I believe this may be why Sennhesier left a hole in the middle of their "acoustical absorber" (which may be sales & marketing term for felt ring.)
     
  5. Serious

    Serious Inquisitive Frequency Response Plot

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    You have to understand that this isnt a ring (like the pic in the HF thread), it is a hole in a cylinder.
    The end of the tube is sealed off (atleast in the versions discussed here) to make it a helmholtz resonator. By changing its depth, diameter and the material inside it we can change its resonant frequency.
    If you just block the hole and stuff it with open cell foam(/whatever works best), it doesn't do shit against the 6khz peak and makes the treble less even and more peaky.
    If we use straws to create isolated chambers that are each tuned to a frequency of about 6khz, we can reduce the peak and smooth out the treble.

    I am still working on improving mine, right now I would just try 3 straws stuffed with open cell foam.
     
    Last edited: Nov 2, 2015
  6. Serious

    Serious Inquisitive Frequency Response Plot

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    Here is a -55db floor measurement of a WIP mod (basically Marv's V0.3). (compare to Marv's 60db, -6db start plots)
    [​IMG]
    My coupler should be comparable to Marv's V1 type coupler (but they are still pretty different so take this with a grain of salt).

    I tried to make the CSD look closer to the V2.95b plots, here are my REW settings:
    (X50;Y450;Z250; 5.21ms time range; 0.25ms rise time; 4.0ms Window (I get reflections if I make it longer); 1/24th smoothing)

    I will not use these settings for most CSDs.

    EDIT:
    -the settings under the Analysis tab in the Preferences were at default
    -I will further experiment and try to optimize my settings and then post them in the measurement systems thread.
     

    Attached Files:

    Last edited: Nov 3, 2015
  7. The Alchemist

    The Alchemist MOT: Schiit - Here to help!

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    Received the Hd800's with Marv's Z28 Mod. (original post here: http://www.superbestaudiofriends.or...-experiments-a-la-hd800s.352/page-4#post-8947

    I have to say they really sound amazing. As Marv stated in his post, they are still bright. but the hardness and glare are extremely reduced. I have listened to HD800's with the Anax 2.0 mod, and Marv's Z28 mod really surpasses the Anax mods IMO. I thought I loved the HD800's before, but with Marv's Z28 Mod they are just an extreme pleasure to listen to. There is still some 6kHz peak, however with the Z28 mod it has decreased quite a bit from stock, making these much more pleasurable to listen to, and for me personally, a lot less fatiguing for long listening sessions. Also, it is very clear that the imaging positioning is much improved. Basically, everything Marv stated in his post on the mod is accurate, even through my mid-fi setup.

    I have only had about 6 hours of listening time with these, since I just received them yesterday, however the mod was immediately apparent. I recommend HD800 owners to definitely try this mod - I am not sure if Marv plans on releasing this mod commercially, but if he does, I would contact him about doing this mod for you if the 6kHZ peak bothers you - this Z28 mod REALLY makes a noticeable difference, even on my mid-fi setup. I am only using JRiver MC21->Bifrost Uber (not Multibit :( ) -> Valhalla 2 with Amperex Orange Globes -> HD800. (Oh Gungnir Multibit where out thou???)

    I can imagine with a higher-end setup, the mod would sound even more spectacular. I do not like to endorse many things unless I am certain they are amazing, but I have to say, for what it's worth, I endorse this mod.
     
  8. The Alchemist

    The Alchemist MOT: Schiit - Here to help!

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    Anyone who has not tried purrin's HD800 Z28 mod should definitely check it out.
     
  9. hifi01170

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    Any progress?
     
  10. zerodeefex

    zerodeefex Grumpiest admin

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    I have access to significantly better 3D printers than what you can access online. We have the first carbon3D printer as well.
     
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  11. hifi01170

    hifi01170 Facebook Friend

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    haha funny! just got myself my christmas gift.... and after a few days of stock listening, was eager to experiment the rug liner... never expected this to be this difficult.
    Just getting the proper shape with the proper dimensions and being able to cut properly the rugliner.... finally I capitulated! maybe the right tools might help... a cutter/scissors. I feel so embarassed!

    ah yeah about taking out the pad... never thought I would need to use this much force... was affraid that i might damange something!
     
  12. Maxx134

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

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    Ok, so it is clear that the enclosure is the culprit,
    So why hasn't anyone adressed (besides Bill_P) the enclosure?

    I have done what would be a messy undertaking to reverse. .

    I have dampened the frame in certain locations with "dynamat extreme"...

    I am posting because I have made noticable positive results with second HD800 on hand for comparison.

    Then I was able to duplicate it on second HD800.

    The effect was a noticable & almost elimination of the diffused trebles.
    Alot of sonic cues and nuances were made very clear and noticable.

    I will post pic and I although I do not have measurment rig to show,
    The improvement was very noticable.
    Added Sibilance seems gone, and recorded sibilance seems more real.

    The only difference that is helping is the added resonator mod I have in place, but that mod did not adress treble resonances like the dynamat damping.

    It was placed in two areas.
    The front metal ring was removed and replaced with the dynamat.
    The rear frame behind the grill in the circular area I will post pic later.

    So my question is has anyone tried to dampen the frame with any results?
    :)
     
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  13. Scubadude

    Scubadude Almost "Made"

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    Hi all,


    Tried making the SDR mod this afternoon and glueing the felt is a mission of note. Got me thinking ... if the resonator is more about exact physical dimensions (which I think is the case given the very specific target frequency) than absorbent properties of the materials, would a resonator laminated from creatology foam not be more effective?


    Anyone tried this? I'm making a pair like that tomorrow, but have no proper SDR resonators to test against, nor do I have access to a test bench.


    Thanks!
     
  14. Benny-x

    Benny-x Rando

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    What ever happened to those pics? I read in another headphone mod thread about the positives of damping the frame, so it's interesting to hear about it here. And especailly so since @purrin said the enclosure was the main culprit, but then no one seemed to be going after it.

    I'm also new to the site and trying to figure our where all these HD800 mod threads are going. This one seems to have just died, then the "order form" version of this thread is up, but there's not much discussion in it about the mods and the effects of the mods. Then later on there talk of matching this with the SDR mod... Can anyone really outline where all this went or if the SBAF HD800 (Z28) mod and the SDR mods are separate? I understand for them to go together the 3 mini Helmholtz resonators would have to be dropped a there's only room for one centre stuffer. By why, did one unanimously win out?
     
  15. Serious

    Serious Inquisitive Frequency Response Plot

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    What @purrin really meant is that reflections between the enclosure and the ear are the main culprit. The Anax type mods and, most recently, the SBAF mod try to address this.
    The SD resonator mod is simply another way of bringing down the treble, but instead focuses on the 6kHz spike only. Like the SBAF mod, it also brings up the upper mids, making the overall frequency response smoother and more neutral. There has been some discussion about the helmholtz resonator mods for the HD800 in this thread. It also seems that there might be some resonances in the hole and filling the hole (which is what the resonator mods in this thread and the shure tip mainly did, I think) does bring down 6kHz but also pushes up 10kHz (depending on the material used). I mentioned this here.
    There has also been some discussion about modding the pads in this thread: 'Neutralizing' my HD800.
    My preference is for using the SBAF mod + SD resonator mod + a variation of the pad mods. I will make a thread about the effect of various HD800 mods measured at the ear canal opening (with a WM-61A mic in a silicone tip) in the near future, as the effects tend to be different (and often greater) than the typical coupler measurements might indicate.

    There has also been some discussion about the effects of enclosure vibration (which is what the dynamat mods try to address) in this thread: A passing idea on vibration analysis...... I think many people didn't try these mods with the HD800 because I think the consensus is that the HD800 is very dead to begin with.
     
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  16. Maxx134

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

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    It really doesn't matter how dead the hd800 plastic is thought to be,

    When the fact is,
    that it has a well known resonant treble peak .

    I was waiting to post because I don't have a measurement setup ready yet to visually show,

    But adding damping definitely cleared up the diffused sound and increased image focus to the two hd800 I had done.

    :)


    I was away and on other projects but will post pics soon.
    Edit:
    I am thinking it is the added mass that is altering the interaction of cup to ear,
    Rather than a "resonance" of the frame or plastic density.
     
    Last edited: Apr 24, 2016
  17. Benny-x

    Benny-x Rando

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    Thanks for outlining how they all worked.

    The Pad mod seems funny to have almost come late to the party. That's a top mod among many other headphones, but I also guess the relative incompatibility of the HD800 earpads have slowed this down? I hope there's progress there. And the chassis damping is interesting too. I read about that in the Denon LA mods with Dynamat and sort of with the HE-6 mods using blue tack to seat and seal the driver to the cups. I'm going to experiment with those 2 ideas on a lot of my headphones as they seem like they'd make some nice differences. I apply the same mass loading and constrained layer damping on my other components to nice effect, so I'll have to give it a shot on headphones. Works with speakers already anyway.

    Looking forward to your measurement rig and what you turn out :)
     

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