The Unthinkable Has Happened: The Sennheiser HD700 is now listenable. The HD750 mod.

Discussion in 'Modifications and Tweaks' started by takato14, Oct 5, 2015.

  1. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    Yes, showing promise but not 100% there. Keep it up. :)
     
  2. FatTeemo

    FatTeemo Rando

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    So I guess my feeling that it only needed the earpad mod has some support?
     
  3. takato14

    takato14 Doglover

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    Yeah, I think the best course of action from here is to retweak it by ear when I get it back until I get it to a point where I'm happy with them (which I wasn't when I sent them out) and then send them back.

    ... or just beg tyll to take the dust covers and damping out and remeasure it with your tail between your legs :x
     
    Last edited: Feb 2, 2016
  4. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    Don't send things if you're not 100% happy. Takes a long time to get there, but you feel less...stupid? after the fact. Something like that.
     
  5. FatTeemo

    FatTeemo Rando

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    That seems easy enough to do. He didn't send it back yet right?
     
  6. Tyll Hertsens

    Tyll Hertsens Grandpappy of the hobby - Special Friend

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    Yeah, I'll take the stuff out and re-measure.
     
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  7. lm4der

    lm4der A very good sport - Friend

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    The FR improvements are amazing. Here is the before and after from Tyll's site:

    before_and_after.png
     
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  8. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    I wonder what's causing the large differences in bass measurements. Can't rule out that the pad mods are doing something funky with achieving proper fit and seal, which could also tie into distortion and how hard you have to drive the headphone. But his measurements do clearly show that it takes a lot more power to bring these up to 90dB.

    I'm curious...what drives does the HD700 use anyway? Are they at all related to the HD6X0 drivers?
     
  9. takato14

    takato14 Doglover

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    It's possible that the connectors on the cable are causing some impedance issues due to almost all of the plating wearing off (cheap piece of shit) or the fact that I've disassembled it so many times that I messed up something somewhere, either in the housing or the driver. The impedance of this transducer is much higher than the other pair tyll measured... Also, as for the fit, this headphone does not rely on a seal, much similarly to the HD800, but since the drivers are now closer to the ear that might be why the 3kHz area has become significantly elevated.

    And no, the drivers are a new design, completely unrelated to the HD6x0 drivers.
     
    Last edited: Feb 3, 2016
  10. ultrabike

    ultrabike Measurbator - Admin

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    Pretty good job Taks!
     
  11. gibosi

    gibosi Acquaintance

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    How noticeable do you think that loss in sensitivity would be? I didn't do the foam mod on the back, only the pad and filter paper, and I do not recall noticing any discernible difference in sensitivity. That is, I am listening at about the same level as before, around 10 o'clock on my amp.
     
  12. takato14

    takato14 Doglover

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    It could just be pair-to-pair variance as well, gibosi. This was a very early HD700 and I disassembled it many times... who knows what microscopic mechanical tolerances I might have fucked up.
     
  13. Lurker

    Lurker Almost "Made"

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    Nice work tak.
    Would like to see this measured again without the foamdisk/paper on the back and front of the transducer.
    It's destroying it's perfectness~ Axel can't make bad drivers.
     
  14. MATEOBCN

    MATEOBCN Rando

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    I did the mod. and seeing that it works. I explain other way, giving them a twist, but the peak of the 6 kHz, without destroying the pads.

    That piece of plastic that fits into the pad, pulling straight out, comes out. on it we will die with a piece of rubber sheet, to be comfortable on your head.

    [​IMG]


    [​IMG]


    When taking measurements and making the decals, I recommend you leave a few millimeters out, to fit perfectly and remain visually beautiful.


    [​IMG]

    When they see that they fit well trimmed pieces of rubber on the handset, as is seen in these 2 pictures, and can put pieces of adhesive zeal duplex in the plastic that fit on the handset, to glue the pieces cut from rubber.

    [​IMG]


    [​IMG]

    Here you can see the end result, how well are the new pads. They have the right size, so that we are comfortable with them. (Maybe whoever has a small head, is more advisable to do the platillas with a piece of thicker rubber. For that best fit the handset.


    [​IMG]


    [​IMG]


    [​IMG]


    I have removed the sponge behind the driver, so they have more cushioning and I've also removed the filter paper which went before the driver.
    Let that are standard, the original handset is only necessary to remove the pads and make templates that I indicate.
    As I checked mod tatako14 doing and seeing measurements Tyll.

    It has been demonstrated that by coming peak resonances have the front pads.
    With this invention, there is even less resonance, the sound now is a mix between a HD600 and Grado.

    Since the driver is practically glued to your ear. It makes like when you change the pads for a finer Grado labs to a headset (Flats) effect.
    The sound is more direct. guitars sharper, smoother acute and the impact of low is more direct. Although the presence lose the lower area.

    Sorry for the English. (I'm using google translator) I hope I have understood something.
     
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  15. takato14

    takato14 Doglover

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    I tried something similar with creatology foam but found myself displeased with the low end.
     
  16. gibosi

    gibosi Acquaintance

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    Would it be too much to ask if you could take out the foam backwave damping as well and then re-measure? It would be very useful to see exactly what the pad-mod is doing by itself in order to determine if any further mods are required.

    Thanks! And I sure hope this is not asking for too much.... :)
     
  17. takato14

    takato14 Doglover

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    Thats a bit excessive. I would advise against this as the part is very difficult to remove.
     
  18. takato14

    takato14 Doglover

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    Alright NOW we're getting somewhere...

    https://dl.dropboxusercontent.com/u...YModifiedTakato14WithDustCoversNoDampling.pdf

    Looks like the pads alone don't quite completely eliminate the 6kHz spike. The ringing, on the contrary, is significantly reduced. Looks like I was targeting the right thing, but didn't get quite enough of the pad out of the way. The upper ranges are at least a bit more fleshed out.

    From here I'm gonna try restuffing the earpads and see what I can accomplish. I suspect the memory foam is more of a culprit than the pleather. Making my own pads is seeming like a viable option at this point too.
     
  19. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    I dunno, man, maybe a very slight 6KHz reduction (could be product variance), but that might look worse than stock overall if I'm being totally honest.
     
  20. takato14

    takato14 Doglover

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    Actually 6kHz is down by about 5dB, with a new spike at around 7kHz. I find 7kHz more tolerable than 6kHz personally, and the peak is no longer outlying -- it doesn't ascend past the rest of the FR anymore, which is a very very important improvement. In stock form the peak was about 5dB louder than any other part of the FR, which is a huge part of why it sounded so metallic. Now it lines up almost perfectly with 3kHz.

    We could take pair-to-pair variance into consideration, but this IS Sennheiser we're talking about. Their quality control is absolutely relentless, especially on their expensive shit.
     
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