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

    Staff Member Friend BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    46,419
    Dislikes Received:
    73
    Trophy Points:
    113
    Location:
    Antarctica
    All art, instructions, material selections and information in this post and following posts (collectively the "SuperBAF HD800 BTA Absorber mod") are covered by theCreative Commons Attribution-Sharealike 4.0 international license. Any derivative work may be sold as long as instructions and art are distributed freely and correct attribution (mention of the name of the mod, SuperBAF and a link to this thread) is maintained.

    See this: http://www.superbestaudiofriends.org/index.php?threads/superbaf-hd800-mod-formerly-btamod.254/
    And this: http://www.superbestaudiofriends.or...800-mod-formerly-btamod.254/page-5#post-25585

    Z28 MOD v0.30 MEASUREMENTS:
    http://www.superbestaudiofriends.or...ks-and-experiments-a-la-hd800s.352/#post-8028
    Z28 MOD v0.30 DRAWING: http://www.superbestaudiofriends.or...-experiments-a-la-hd800s.352/page-3#post-8328
    LISTENING TEST: http://www.superbestaudiofriends.or...-experiments-a-la-hd800s.352/page-4#post-8947
    @Serious ' INDEPENDENT IMPLEMENTATION AND MEASUREMENTS: http://www.superbestaudiofriends.or...-experiments-a-la-hd800s.352/page-3#post-8490

    --
    BEGIN ORIGINAL POST

    First of all, we'd like to thank Jude for posting the photos of the drivers and inside of the HD800S cups. This is a branch of the HD800S thread, specifically concerning the Helmholtz resonator concept in the driver. Note that this approach is very different from the prior type mods which seek to reduce the diffraction and resonant effects of the cups.

    Could be a semi-closed. The calculations don't seem to imply the need for multiple cavities. Too many small cavities might also present issues with airflow.

    Anyway, a very cheesy quick mockup below. I used a drinking straw encased around with foam. Cheap tape was used to wrap around the foam to prevent air leakage (otherwise the resonator won't work.)

    Figure 1: HD800 with DIY Resonator v0.1
    IMG_20151025_134645837.jpg

    Figure 2: Measurements of stock HD800 and HD800 with DIY Resonator
    PURPLE = cheesy resonator v0.1 GREEN = stock
    HD800res.png

    These are the V1 sponge method measurements. I marked placement of the cup precisely and took multiple measurements to make sure I had it right. I also placed the dust covers back on (so more roll-off seen in the last octave).

    A bit smoother and more extension in the treble.

    I look forward to Bill-P's tweaks.
     
    Last edited: Apr 1, 2016
    Lyer25, dark_energy, Serious and 9 others like this.
  2. Bill-P

    Bill-P Level 42 Mad Wizard

    Friend
    Joined:
    Sep 25, 2015
    Likes Received:
    2,963
    Dislikes Received:
    13
    Trophy Points:
    93
    Location:
    San Jose, CA
    Thanks for doing this, Marv.

    Yeah, the effect is just as I suspected... quite slight. Putting a piece of foam donut in the back also does about the same thing. I'm torn on whether or not the "improvement" is really worth it. It actually sounds a bit on the brighter side to me, although treble is smoother.
     
  3. purr1n

    purr1n Finding his inner redneck

    Staff Member Friend BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    46,419
    Dislikes Received:
    73
    Trophy Points:
    113
    Location:
    Antarctica
    This might be effective in combination with a lite application of the prior type mods. Overall brightness from mid treble on up can be reduced with use of the dustguards.
     
    Last edited: Apr 1, 2016
  4. OJneg

    OJneg The Most Insufferable

    Friend BWC
    Joined:
    Sep 25, 2015
    Likes Received:
    3,649
    Dislikes Received:
    13
    Trophy Points:
    113
    Location:
    Grand Rapids
    This thread is now golden. If I were working at Sennheiser I would be having a conniption.

    From the look of it the existing enclosure damping options are more effective, but I think further analysis (plots and ears) is needed.
     
    Last edited: Oct 25, 2015
    AustinValentine likes this.
  5. paranoidroid

    paranoidroid Friend

    Friend
    Joined:
    Sep 30, 2015
    Likes Received:
    135
    Dislikes Received:
    0
    Trophy Points:
    43
    Location:
    San Francisco
    I can't seem to get the math to work right when using the entire earcup as the resonating spring and venting to the outside, just too much volume to have an effect at 6khz. Although your test seems to show a ~1db difference and in the right direction. I still suspect there's something more to it..but maybe not *shrug*.
     
    Last edited: Oct 25, 2015
  6. purr1n

    purr1n Finding his inner redneck

    Staff Member Friend BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    46,419
    Dislikes Received:
    73
    Trophy Points:
    113
    Location:
    Antarctica
    Indeed, I don't think some of the newer folks here are aware of the earlier work which was done on the HD800:

    Figure 3: Response of Raw Driver (bare driver removed from enclosure)
    Top: sponge coupler
    Bottom: solid plate coupler
    hd800 raw driver.gif
    IMG_20151025_171614099.jpg

    Figure 4: HD800 Frequency Response Measurement
    In the cups, i.e. measured normally
    HD800.gif

    It would appear that the treble peaks are caused more by the enclosure than the driver. The frequency response of driver itself is actually quite smooth.
     
    Last edited: Oct 25, 2015
    jsgraha, ultrabike, FlySweep and 2 others like this.
  7. Chris F

    Chris F Boyz 4 Now Fanatic - Friend

    Friend
    Joined:
    Sep 27, 2015
    Likes Received:
    793
    Dislikes Received:
    1
    Trophy Points:
    93
    Location:
    Ottawa, Canada
    Looks like you traded some 8K for 10K so they are closer to equivalent. It would be great if the official version could get 8K and 10K flat with each other. I'm guessing that would sound pretty good.
     
  8. purr1n

    purr1n Finding his inner redneck

    Staff Member Friend BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    46,419
    Dislikes Received:
    73
    Trophy Points:
    113
    Location:
    Antarctica
    I believe you mean 6kHz, not 8. Overall the peaks are broader, and that is a good thing.

    Also, everyone should keep in mind that this tweak was done in two minutes with materials I had available on my desk and in the kitchen. I wanted to see if it was even worth pursuing.
     
  9. purr1n

    purr1n Finding his inner redneck

    Staff Member Friend BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    46,419
    Dislikes Received:
    73
    Trophy Points:
    113
    Location:
    Antarctica
    Here are the results after some minor adjustments. This time, the peak at 6kHz is brought down without elevating 10kHz.

    Figure 5: Measurements of stock HD800 and HD800 with DIY Resonator Tweak 0.2
    GREEN = cheesy resonator v0.2 YELLOW = stock
    HD800 tweak 2.png
     
    eddypoon, jsgraha, JoelT and 3 others like this.
  10. OJneg

    OJneg The Most Insufferable

    Friend BWC
    Joined:
    Sep 25, 2015
    Likes Received:
    3,649
    Dislikes Received:
    13
    Trophy Points:
    113
    Location:
    Grand Rapids
    I still thinking that reducing the 4k dip goes a huge way to making things sound better. As your plots show, the 6k peak isn't that bad relative to the level of bass, but things sound so uneven because of that weird lower treble recession. Certain enclosure modifications can help fix that I've found
     
  11. purr1n

    purr1n Finding his inner redneck

    Staff Member Friend BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    46,419
    Dislikes Received:
    73
    Trophy Points:
    113
    Location:
    Antarctica
    Making incremental progress... (sealed off the straw from the outside)

    Figure 6: Measurements of stock HD800 and HD800 with DIY Resonator Tweak 0.25
    GREEN = cheesy resonator v0.25 YELLOW = stock
    HD800res2.5.png
     
    Last edited: Oct 26, 2015
    firev1, jsgraha, Freddy1201 and 5 others like this.
  12. TMRaven

    TMRaven Friend

    Friend
    Joined:
    Sep 27, 2015
    Likes Received:
    593
    Dislikes Received:
    2
    Trophy Points:
    93
    Wonder where this 'greatly increased bass extension' comes into play with this resonator, or if it's also the work of a new diaphragm.
     
  13. Ali-Pacha

    Ali-Pacha Friend

    Friend
    Joined:
    Sep 27, 2015
    Likes Received:
    261
    Dislikes Received:
    0
    Trophy Points:
    63
    You guys are crazy. I like it.

    Ali
     
    ultrabike and recarcar like this.
  14. spoony

    spoony Spooky

    Friend
    Joined:
    Sep 28, 2015
    Likes Received:
    241
    Dislikes Received:
    2
    Trophy Points:
    43
    Now that's something!
     
  15. purr1n

    purr1n Finding his inner redneck

    Staff Member Friend BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    46,419
    Dislikes Received:
    73
    Trophy Points:
    113
    Location:
    Antarctica
    More progress. Here's a three chamber design. This one is the most effective so far. The chambers are sealed on one end - on the outside. I've actually tried just stuffing that entire middle area with foam without chambers or tubes - that approach doesn't work.

    Figure 7: FR Measurements of stock HD800 and HD800 with DIY Resonator Tweak 0.30
    GREEN = cheesy resonator v0.30 YELLOW = stock
    20151025_204744.jpg
    HD800res3.png

    Figure 8: Impulse Response of stock HD800 and HD800 with DIY Resonator Tweak 0.30
    hd800res3IR.png

    Less overshoot, tighter rise, reduced ringing amplitude (but same decay time).
     
    Last edited: Oct 28, 2015
    zonto, SSL, FlySweep and 12 others like this.
  16. Judeus

    Judeus Almost "Made"

    Executed
    Joined:
    Sep 28, 2015
    Likes Received:
    213
    Dislikes Received:
    1
    Trophy Points:
    43
    Location:
    summit-fi purgatory
    it looks like from the official pic of the hd800s that there is another "resonator" ring around the inside of the second circle of the black plastic piece that protects the driver
     
    maibuN and kapanak like this.
  17. kapanak

    kapanak Canucklehead - Friend

    Friend
    Joined:
    Sep 27, 2015
    Likes Received:
    309
    Dislikes Received:
    4
    Trophy Points:
    63
    Not many of us have access to what you have here, so I really appreciate the effort, Marv! You really are onto something here! Look at the peaks going down and the valley rising! Woot!
     
  18. kirayamato

    kirayamato Friend

    Friend
    Joined:
    Oct 18, 2015
    Likes Received:
    93
    Dislikes Received:
    5
    Trophy Points:
    28
    this is some next level stuff you really know your stuff XD
     
  19. purr1n

    purr1n Finding his inner redneck

    Staff Member Friend BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    46,419
    Dislikes Received:
    73
    Trophy Points:
    113
    Location:
    Antarctica
    As Ali said, we are crazy. I'll probably hang it up now and see if Bill-p can take it to the next level. FYI: I added impulse response plots up above. I think TheAlchemist is going to get a nice HD800. I still need to perform a full subjective test on the tweaks, and TheAlchemist's HD800 is going to be the guinea pig. The changes won't be huge (and they shouldn't be); but I don't think anyone will complain of less 6kHz peakage, the slight lift to the mids, while still maintaining stock bass and mid/high treble. There is actually a way to tone down 10kHz, but I want to leave it as it.
     
    Last edited: Oct 25, 2015
  20. TMRaven

    TMRaven Friend

    Friend
    Joined:
    Sep 27, 2015
    Likes Received:
    593
    Dislikes Received:
    2
    Trophy Points:
    93
    Now we're getting somewhere! About 2.5db less response at the 6khz peak and about 1db more at 2-3khz-. The faster impulse response is great as well. With such progress in only one day using mostly rudimentary materials, I'm curious as to how far you can take this over a period of time, and I'm curious as to how the HD800 measures with stock vs anax mod only vs resonator only vs anax mod and resonator.
     
    maibuN likes this.

Share This Page