Modding a Headphone to Reach a Target Response

Discussion in 'Audio Science' started by cskippy, Jan 24, 2016.

  1. cskippy

    cskippy Creamy warmpoo

    Friend MZR
    Joined:
    Oct 14, 2015
    Likes Received:
    4,042
    Trophy Points:
    113
    Location:
    Tempe, Arizona
    Short and sweet to start. I'll add more later...

    Backstory

    From the first listen to the HE-6 I immediately thought there was something off about them. Some claimed they needed break in, others claimed to try various pads (which did help to some extent). However there was always treble glare and just a overall brightness to the sound. I could tell there was potential even compared to my fully modded HE-500. The bass was more refined and had articulation and differentiation between notes. Definitely NOT one not bass! I started playing around with different materials to try and tame the treble and etch that I was hearing. I was going all by ear and wanted to match the gold standard reference the HD650.

    Frequency response of my mods done by ear
    [​IMG]
    I was pretty happy with these mods as I was trying to reach a -10dB slope target from 20Hz to 20kHz. However, there are inconsistencies like the 1.3kHz peak, the dip in the midrange, and the slight treble bump at 8kHz.

    I decided to build a measurement rig to get accurate and repeatable results.

    HD650 for reference
    [​IMG]
    [​IMG]
    [​IMG]

    My current mods for HE-6
    [​IMG]
    [​IMG]
    [​IMG]
    Here is an overlay of HE-6 modded vs HD650
    [​IMG]

    HE-6 with Audeze pads and no grills (this is soooo close to sounding right)
    [​IMG]

    I'll post pictures of my measurement rig later.
     
    • Like / Agree Like / Agree x 3
    • List
  2. cskippy

    cskippy Creamy warmpoo

    Friend MZR
    Joined:
    Oct 14, 2015
    Likes Received:
    4,042
    Trophy Points:
    113
    Location:
    Tempe, Arizona
    Sound Impressions

    Although I can't A/B these I've spent enough time modding them to understand when something sounds off. The HD650 is also a great tool to check with.

    The first thing that I noticed when listening to the current mods is that the headphones are obviously less bright and tizzy from the stock 10kHz beak. The bass is better integrated and the midrange is less scooped out. Guitars come forward with the appropriate bit and voices are better placed in the mix.

    The next thing that I realized was how much better detail was revealed. The more linear frequency response with less deviation from the intended -10dB slope lets timbre and intended coloration come through so much better. Pitch differentiation is also vastly improved, especially in the bass. Sub bass response is clearly audible down to 20Hz but more importantly the level stays strong and doesn't taper off like the stock form. This truly has bottomless bass.

    Pictures of mods will be shown at a later time as they are further tweaked and then cleaned up for public consumption!

    These headphones will be at the Arizona Phoenix Headphone meet at the Burton Barr Library on the 30th.
     
    Last edited: Jan 25, 2016
  3. cskippy

    cskippy Creamy warmpoo

    Friend MZR
    Joined:
    Oct 14, 2015
    Likes Received:
    4,042
    Trophy Points:
    113
    Location:
    Tempe, Arizona
    I spent some time applying a soundcard correction to better match my HD650 measurements to Purrin's.

    HD650 Frequency Response with SBAF Compensation applied:

    [​IMG]

    Here is the SBAF curve on my modded HE-6 (super zoomed in):

    [​IMG]
     
    • Like / Agree Like / Agree x 3
    • List
  4. spoony

    spoony Spooky

    Friend
    Joined:
    Sep 28, 2015
    Likes Received:
    502
    Trophy Points:
    93
    Very well done!
     
  5. cskippy

    cskippy Creamy warmpoo

    Friend MZR
    Joined:
    Oct 14, 2015
    Likes Received:
    4,042
    Trophy Points:
    113
    Location:
    Tempe, Arizona
    Thanks! I have more ideas on how to improve the results but I'll need a CNC for better variation on design. I'll update as I make more progress.
     
  6. Audio Zenith

    Audio Zenith Custom Title KGB

    Friend
    Joined:
    Sep 27, 2015
    Likes Received:
    353
    Trophy Points:
    63
    Looks like a GREAT JOB! Only if 650 was totally neutral, nevertheless it's one of the closest so cudos to you!
     
  7. ohhgourami

    ohhgourami Friend

    Friend
    Joined:
    Sep 27, 2015
    Likes Received:
    606
    Trophy Points:
    93
    Location:
    SGV, CA
    At this point, I don't even give a shit about the curves; I just want to see your mods.

    I'm glad others still hear the potential in these.
     
  8. cskippy

    cskippy Creamy warmpoo

    Friend MZR
    Joined:
    Oct 14, 2015
    Likes Received:
    4,042
    Trophy Points:
    113
    Location:
    Tempe, Arizona
    All will be revealed once I get the mods finalized. Also, distortion should be better than it shows. I am using the Liquid Carbon on 3x gain almost maxed to get 90dB @ 1kHz.
     
  9. ohhgourami

    ohhgourami Friend

    Friend
    Joined:
    Sep 27, 2015
    Likes Received:
    606
    Trophy Points:
    93
    Location:
    SGV, CA
    Are they in addition to some of my mods?
     
  10. cskippy

    cskippy Creamy warmpoo

    Friend MZR
    Joined:
    Oct 14, 2015
    Likes Received:
    4,042
    Trophy Points:
    113
    Location:
    Tempe, Arizona
    No. Using stock velour pads. I might try a version with Audeze Pads but for now I want to get this nailed down.
     
  11. ktmracer12345

    ktmracer12345 Rando

    Joined:
    Feb 10, 2016
    Likes Received:
    14
    Trophy Points:
    3
    Location:
    Gilbert, Arizona
    I don't have a cnc, but I have a 3D printer. If you have a CAD file/3D printer file, I'll print you whatever you need.
     
    • Like / Agree Like / Agree x 2
    • List
  12. cskippy

    cskippy Creamy warmpoo

    Friend MZR
    Joined:
    Oct 14, 2015
    Likes Received:
    4,042
    Trophy Points:
    113
    Location:
    Tempe, Arizona
    Hey ktmracer12345 that's a very generous offer! I might take you up on that. I'll have to do some work on that but I have some ideas.
     
  13. cskippy

    cskippy Creamy warmpoo

    Friend MZR
    Joined:
    Oct 14, 2015
    Likes Received:
    4,042
    Trophy Points:
    113
    Location:
    Tempe, Arizona
    I'd like to share my current mods with everyone. These are NOT FINAL but are pretty close to the intended target. I hope to reduce distortion and clean up the CSD a little, although my settings are all wack so it's probably better than it shows...

    I'll start with my modded HD650 ( you can see the mods in the HD650 measurements thread) and then applied EQ to further flatten and improve the frequency response.

    [​IMG]L HD650 modded plus EQ by Chris Riley, on Flickr

    CSD

    [​IMG]L HD650 modded plus EQ CSD by Chris Riley, on Flickr

    Spectro

    [​IMG]L HD650 modded plus EQ Spectro by Chris Riley, on Flickr

    This sounds fantastic but is cheating obviously. I wanted to see how close I could come with just acoustic modding. Here is the HE-6 in it's current state:

    [​IMG]L HE-6 modded by Chris Riley, on Flickr

    CSD

    [​IMG]L HE-6 modded CSD by Chris Riley, on Flickr

    Spectro

    [​IMG]L HE-6 modded Spectro by Chris Riley, on Flickr

    Subjectively this sounds very close to the modded HD650 with a slightly less deep soundstage and microdetails, especially hard left/right are a little harder to hear due to the planar design and being open. The last octave sounds like it shows. I would like to have that raised up for a touch more air but am more pleased with the fact that the annoying stock 10kHz peak is GONE. Yay!

    Current mod pics:

    Microfiber cloth with a quarter sized hole in the middle on the inside of the driver. If you try duplicating these mods BE WARNED that different microfiber clothes yielded very different changes in the frequency response.

    [​IMG]HE-6 current mods by Chris Riley, on Flickr

    Yellow Artist Sponge cut to appropriate depth. It can be bought from Michael's. It's the royal langnickel synthetic sponge pack

    http://images.michaels.com/cms/mich...0001L0000E000020000J0001Y0000200KL8.ViewAsset

    [​IMG]HE-6 current mods by Chris Riley, on Flickr

    1mm felt disk diameter 4.75cm underneath 2mm closed cell foam ( Darice 2mm foam from Michaels).

    [​IMG]HE-6 current mods by Chris Riley, on Flickr
     
    • Like / Agree Like / Agree x 2
    • List
    Last edited: Feb 12, 2016
  14. MF_Kitten

    MF_Kitten Banned per own request

    Banned
    Joined:
    Jan 1, 2016
    Likes Received:
    180
    Trophy Points:
    43
    Closed cell foam, eh? I've heard a lot of "open cell or go home!", so this is very intriguing! I always figured it was overly cautious. Cool mods man, I like the idea of what these can sound like if someone did a full ZMF/Alpha type makeover to them.
     

Share This Page