HD800 Resonator Tweaks and Experiments a la HD800S

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

  1. Clemmaster

    Clemmaster Friend

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    Marv, can you please use a different color set than Yellow / Green? The Color blinds (and dogs) will thank you!
     
  2. frenchbat

    frenchbat BritishBat's arch enemy - Friend

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    A quick question Marv. Did you push the resonator in the driver's integrated dust cover ? Did you cut it ? I can't really see from your pics.
     
  3. purr1n

    purr1n Finding his inner redneck

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    I cut it out. You can cut just the center portion and leave the rest of it over the driver intact.
     
  4. frenchbat

    frenchbat BritishBat's arch enemy - Friend

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    That's what I thought, not really a problem, as it plugs the hole shut, and dust can't enter. Thanks Purrin.
     
  5. purr1n

    purr1n Finding his inner redneck

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    The center cavity is isolated. The magnet assembly surrounds it. No worry about dust even it if gets in there.
     
  6. kirayamato

    kirayamato Friend

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    what are you finding out with actualy listening tests @purrin getting to the next level?
     
  7. Bill-P

    Bill-P Level 42 Mad Wizard

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    Just wanted to add my own tests...

    No photos as I'm lazy ass. Sorry...

    But I didn't want to try anything destructive (for aesthetic reasons and also because I'm just not "sure" about the "improvements" yet), so I tried putting closed-cell foam, open-cell foam, felt, etc... rings in the back of the driver around the whole instead. Technically, this is behind the screen, and the screen is permeable, so I think it's *almost* equivalent to what's being done here.

    Objective measurements do suggest that the peak does shift slightly downward and the higher peaks do shift slightly upward with this.

    Subjectively, I do not like the sound. At all. Much more piercing than stock for some reason. Hopefully, Marv is getting better luck with the front-damped/tube version.
     
  8. Serious

    Serious Inquisitive Frequency Response Plot

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    I also tried this.

    I used 3 straws with a diameter of around 8mm and put some closed cell foam in them.

    Here are my measurements:
    [​IMG]
    My coupler is sort of a bad compromise between the V1 and the V2 type.
    EDIT: Will post pics and descriptions of my measuremt setup later, just not today.

    My measurements also show a rise in volume the 1-4khz (and also 10khz) region with a reduction between 5-8k but only about 1db.
    Keep in mind these results are with a version of the anax mod installed (basically anax 2.0 with tyll size foam rings).
    I'm sure Marv's V0.3 mod is better, I will try to improve mine tomorrow. (I think I didn't quite manage to seal it off perfectly, will look into other methods for that tomorrow)

    I think the tonality did indeed get a little better but I could just be imagining things.


    @Bill-P I'm sure the results from this are very different than from just putting foam behind the hole without changing its tube diameter.
     

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    Last edited: Oct 26, 2015
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  9. The Alchemist

    The Alchemist MOT: Schiit - Here to help!

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    Now what is the ideal measurements we want to see with HD800 Mod - I mean what would the measurements look like if the mod achieves what is being aimed for?
     
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  10. Bill-P

    Bill-P Level 42 Mad Wizard

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    Good question. I'd say... I (we?) have no idea. :punk:

    The way I've been going about it is... if there are subjective differences that are positive to my ears, then... it passes. Sometimes changes don't even show in measurements (really!), but they are still there subjectively, so... either my coupler is broken, or something weird is going on. Some stuffs make quite an obvious difference like this experiment that Marv is doing here, but I think... a crazy amount of reflection damping would still make more of a difference than this.

    As an aside, here is what I'm shooting for...
    [​IMG]

    It's not shown, but subjectively, my HD800 sounds a lot fuller and bassier than the stock pair. I think bass on my pair should at least be as elevated as the next highest midrange peak. I don't think the 1dB reduction at 6KHz makes any difference. It's still slightly harsh/peaky, though not annoying. I can probably find 1-2 songs in my entire library that are kinda hard to listen to, but other than those, it's pretty good.

    My goal was to push everything to be about the same as the peak at 6KHz... and I think I've been fairly successful there.

    And even this version still sounded brighter than HD650 (you can ask @drfindley), but you wouldn't see that in the measurement at all. HD650 would look like it has more treble/air, but... subjectively, that's just not the case. I think the internal reflections of the HD800 is interfering with our ability to measure it by quite a good amount.

    As an aside, I think we can achieve a fairly listenable HD800 without resorting to irreversible mods. If you have to destroy a $375 driver (I got this figure from the guy who worked on that DIY closed-back headphone) in order to get at this, then you might as well spend that amount on new toobz! ;)
     
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  11. purr1n

    purr1n Finding his inner redneck

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    It could be possible the lining material type mods play such a large factor that the resonator tweak doesn't seem to do much. I can't reiterate enough that the 6kHz peak is caused more by the enclosure / cup itself than by the driver. Are there any differences with the impulse response?

    Also, I figured I'd post this here for clarity in case anyone missed it in the HD800S general discussion thread.
    [​IMG]
     
    Last edited: Apr 1, 2016
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  12. The Alchemist

    The Alchemist MOT: Schiit - Here to help!

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    @purrin - I know it has been mentioned before, but thank you for all of your hard work and experimenting, tweaking etc on the HD800. I am very grateful as I am sure a lot of members are, for your willingness and work on experimenting with this. And thank you to everyone else who is contributing graphs, measurements etc. It is very appreciated.
     
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  13. kapanak

    kapanak Canucklehead - Friend

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    Marv, can you measure the diameter of the cavity in the middle of the driver? Preferably in millimetres. Also the depth please :)
     
  14. purr1n

    purr1n Finding his inner redneck

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    Diameter = 9/16"
    Depth = 9/32"

    25.4mm = inch
     
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  15. cooperpwc

    cooperpwc Friend

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    This thread is awesome. And I will pile on the view that Senheisser has nothing to worry about in terms of sales. Some of us interested parties do not have the DIY instincts and skills while the general public just isn't going to go there.
     
  16. Stapsy

    Stapsy Friend

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    Really cool stuff Purrin. I had given up on my HD800 modding efforts but this has given me some new life. It is tough to pull the trigger trying a permanent alteration though.
     
  17. Serious

    Serious Inquisitive Frequency Response Plot

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    I Improved mine by making sure it was completely sealed off and I'm now using felt instead of the closed cell foam that I used before.
    I also detached the cup from the headband assembly to make modding easier, which results in a different FR, so these aren't comparable to my first measurements
    [​IMG]
    The difference is about 2.5db now

    I still need to do the other cup so no subjective impressions for now.
    I don't have the impulse response right now (need to find my ARTA key) but the CSDs look pretty much the same (the mod already gets nearly completely rid of the resonance on my coupler)
     

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  18. George Mhmmm

    George Mhmmm Acquaintance

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    Wow this mod seems to be making a real difference in taming the 6k peak and bringing up the mids ever so slightly. Most cup mods thus far seem to bring up the mids to make the 6k peak seem more in line, but this one actually smooths out the treble spikes themselves.

    Great work everyone.
     
  19. spoony

    spoony Spooky

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    Has anyone played with this kind of foam? It's high-density open-cell foam which I found to be effective with my T50RP mods. What happens if one were to plug the whole center of the driver assembly with foam instead of using 'resonators'?
     
  20. Tyll Hertsens

    Tyll Hertsens Grandpappy of the hobby - Special Friend

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    Arnaud turned me onto Melamine foam. I think those makeup wedges might be latex.

    You can get Malamine blocks at your local grocery store.

    [​IMG]
     
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