AKG K7xx modding

Discussion in 'Modifications and Tweaks' started by fishski13, Oct 13, 2015.

  1. fishski13

    fishski13 Friend

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    there may be all of two or three guys around these parts that enjoy listening to the AKG 7xx variants, but i thought a repository of mods and links to share would be helpful for those interested in modding the AKGs to suit their personal preferences. while i've not encountered a perfect headphone for my tastes, i think they do a lot right, especially if your willing to try EQing or modding.

    i've owned at least one K7xx variant on and off over the past decade, currently the K701 and K7XX. it's been a love/hate relationship. yes, the peaks starting in the mid-highs at 2KHz to high treble can be pesky, or for some, even painful. combined with a leaner bass response, i'm guessing the AKGs can feel like red hot poker shoved in the ear canal.

    i'm not looking for perfect metrics. if any deviation from 'neutral' has pleasing flavor enhancing properties, i'm all in. i like to have my music served up with a good sense of note attack, dynamics, and clean decay - a little on the lean side is better than cuddly and over-ripe. so a peak here and there in FR can be a good thing. you might like to rock on another porch. i like to get together with friends and rock on their porches from time to time as well.

    the AD2000 would be the perfect all-around headphone for my tastes, but sometimes i feel it's lacking in fine detail. it partners swell with poor recordings though, or while listening to Spotify, and i don't feel like i'm missing out on anything. it's also not a soundstage champ, and lacking in bass depending on my mood. the ATs resolving powers of dynamics, large and small, and ability to convey a musical line more than make up for other deficiencies. like searching for the perfect Old Fashioned to sip on while i rock on my porch, so goes finding the 'perfect' headphone.

    my simple mods aren't anything novel. no fish 1.0, 2.0 etc. no measurements. just my ears. here are a couple of excellent links that i springboarded from. props to the authors.

    http://headaudio.weebly.com/clanky/akg-k701-recenze-modifikace-and-more

    http://www.head-fi.org/t/411268/the-akg-k701-friend-or-foe-mods-that-may-help-others

    the K7XX and K701 are very different sounding headphones, primarily due to the different sonic qualities of the pads. swap the pads and you can make either sound like the other, but not quite - there are still some differences, albeit small and notably in the treble. while i find the memory foam of the K7XX very, very comfortable, i can't say i've been able to get either AKGs to sound good with them in place. bass is too thick and bloated, bleeding upwards in FR - total deal breaker. while the prickly lower treble to high treble penetrate with my well worn K701 pads, they're less offensive on the K7XX vs the K701 - the K701 has more treble issues to my ears with either pad in place. since i haven't been able to find the right mod to make the memory foam pads sound pleasing, i've focused on taming the treble peaks of the K701 pads on the K7XX. i'll experiment more with the memory pads down the road, but probably just with the K701.

    my modding thus far has only consisted of playing around with some dumb felt i found in my kids' crafting bin. i had the color choice of black or white. i went with white since the felt alignment would be easily seen through the center mesh of the pads. i took measurements of the stock baffle foam with a micrometer and created/printed in ACAD a template to cut out the felt to near exact dimensions of the foam (cutting felt with a Fiskars isn't an exacting endeavor no matter what). i made up a couple sets of felt donuts and experimented with different layering schemes.

    -omitting the foam and replacing with one layer of felt was an improvement, but treble was still too aggressive.
    -two layers of felt tamed the treble, but the bass sounded over-dampened and attenuated too much for my liking. i also felt that there was a loss in fine detail in the treble. i guess one could entertain the "one man's detail is another's hyped bright super nova in the ear" argument here.
    -one felt layer on top of the stock foam was getting closer to the ideal, but bass was still MIA. i need less felt for less bass attenuation, but too little and treble gets troublesome.
    -cutting roughly 1/3 out of the felt donut and playing around with placement has yielded an acceptable improvement and where i'm at right now. rotating the cutout created subtle changes in soundstage and FR. since i don't have another K7XX to A/B mods with, i just tried positioning the cutout up, down, left, and right, and picked one that i thought sounded the best.

    time will tell, but i really like the sound coming from the K7XX now.
    [​IMG][/IMG]
    [​IMG]
     
  2. Friday

    Friday Friend

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    Heh been waiting for thread like this. I removed all the felt/foam rings and discs that came with it, did the bass port mod, and dampened using bits of sorbothane. No embedded pics though, since I'm not yet a friend.

    https://www.flickr.com/gp/128476680@N02/13hNd7

    Edit: It's the K7XX btw
     
    Last edited: Oct 13, 2015
  3. logscool

    logscool Friend

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    I've been working on some mods for this headphone and will post some stuff asking with measurements when I get it a little more final and have time. I think this headphone (K7XX version) has some nice qualities to it but the peaky treble is just too annoying after a bit.
     
  4. gixxerwimp

    gixxerwimp Professional tricycle rider

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    I find the bass with the K7XX and stock pads is already adequate in quantity. Did removing the tape from the back of the driver increase bass response? Did the sorbothane then tame it back down?
     
  5. Friday

    Friday Friend

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    I didn't really find an increase in bass response, although I did the mod on a whim after a few minutes of listening so take that part with a pinch of salt. However, I did find that putting a piece of sorbothane on the plastic casing underneath the "nipple" on the back did help to tame the bass a bit so that might have a similar function to the tape. Also, removing the sponge around the driver in the stock K7XX seemed to increase the treble detail (and possibly fatigue depending on the listener) at the cost of some bass and warmth, which the sorbothane may bring back depending on the amount used.
    I guess it seems kinda counterproductive in that I might end up using sorbothane to do the original sponge's job, but I just didn't like the idea of part of the driver being covered. Also, it feels more comfortable as the sorbothane is not in a position that irritates the edge of my left ear like the sponge did. It might also have been a bit hasty of me to post the picture as I'm still experimenting with different sizes and positioning of sorbothane around the driver, which have subtle but noticeable differences in the sound.

    I'm still using the stock pads as well, though I'm considering removing the dust covers provided I can find spare stock pads in case that option doesn't work out.
     
  6. Deep Funk

    Deep Funk Deep thoughts - Friend

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    K601 ear pads can have beneficial effects.
     
  7. Friday

    Friday Friend

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    How so?
     
  8. Deep Funk

    Deep Funk Deep thoughts - Friend

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    More bass, less treble but the effect is subtle. On my K500 this effect was much appreciated, especially regarding low end.
     
  9. Friday

    Friday Friend

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    Hmm not too sure if I'd like that on the K7XX but I'll keep an eye out for those anyway.Thanks for the heads up!
     
  10. spoony

    spoony Spooky

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    Thanks for the write-up! My main gripe with the K7XX is the dip around 3-4 KHz which makes stuff sound hollow and unfocused in comparison to my other cans, is this problem alleviated with the use of the K701 pads?
     
  11. fishski13

    fishski13 Friend

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    no major dip sweeping with SineGen. with the K701 pads, the freq curve is closer to the stock K701. my goal is to create a more delicate, kinder K701 without sacrificing resolution. it's still a lean, treble-tilting can.
     
  12. spoony

    spoony Spooky

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    Thanks.

    Any place to get legitimante K701 pads for a reasonable price?
     
  13. fishski13

    fishski13 Friend

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    nope. the service and support from Harman Kardon has always been excellent in the past though.
     
  14. spoony

    spoony Spooky

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    Taking a page from the HD800 modding efforts, I tried this:

    IMG_0393.JPG

    And lo and behold, most of my gripes with the K7XX were fixed! Image seems smaller in dimension but better defined, specially the center image. Bass less bloated, now is proper warm. Treble smoothed, but I added an additional ~1mm thick hard felt disc behind the non-slip mat donut to further smooth the 8Khz region because I hate treble nasties, some people may not need this. Downside is if you have larger ears they will probably touch the mat, mine don't. You also have to fiddle a bit more with the position to find the sweet spot.

    Material is your run-of-the mill anti-slip shower mat. I found mine in the local supermarket.

    This is with stock K7XX pads. Highly recommended!
     
  15. Friday

    Friday Friend

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    So my fingers got too itchy and I went ahead to remove the dust covers from the stock earpads. The K7XX ended up sounding more diffuse overall (less resolving?) to my ears. Strongly discouraged. Thank goodness I had the sense to remove them carefully and they were more or less intact apart from a few frays, and can keep them stuck on the adhesive left behind so long as I don't try to remove the earpads. Now I have to look out for a fabric glue that can stick to plastics as well.
     
  16. logscool

    logscool Friend

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    I will have to try that anti-slip mat and do some playing around with that. I had gotten sort stuck in my modding of this headphone cuz I couldn't seem to find any combinations that removed the annoying treble spikes significantly enough without making the phone sound much more recessed and less resolving. It's not that I don't like treble it's just that I find the peaks get bothersome after a bit.
     
  17. spoony

    spoony Spooky

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    I'm starting to think the ear chambers are just too roomy with these, enabling more interactions to happen at many frequencies. The mat donut is definitely worth a try ;)
     
  18. Friday

    Friday Friend

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    Haven't gone out to grab an anti-slip mat yet, but had another experiment with sorbothane, this time on the outer ring of the frame i.e. the region directly covered by the earpad foam. Unlike previous damping experiments, this one seemed to reduce the bass instead, and the treble was more prominent without being more fatiguing. Funnily enough, it didn't sound anaemic, rather the lower details seemed to be missing. Might try out smaller pieces of sorbothane to see if they tighten the bass instead of wiping out details completely (they were about 2cm by 1cm this time, probably going to halve them)
     
  19. fishski13

    fishski13 Friend

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    Spoony,
    I really like your mod with my K701 sporting the K7xx pads. My non-skid rug mat appears to be more open though. I like the more comfortable K7XX pads on the K701 since I feel less pressure of the headband bumps on top of my head. I think this one's a keeper. Thanks!

    My K7XX/K701 pads mods need some work. After living with these for awhile, they're still too lean, spicy, and splashy. So I opened the bass port. Super awesome with the K701 pads, extending and elevating bass. Not a huge difference, like the K7XX pads, but it adds a little extra gravitas and warmth without sluggish bloat. Bass sounds less 'critically damped' and 'breathes' a little better. I think I still need to do some more tuning with the treble, but I feel like i'm getting closer.

    I wouldn't recommend the bass port mod with the K7XX pads unless you like you bass served up sloppy, fat, and loose. The mod is easily reversible if you're able to remove the yolk/gimbal housing, otherwise getting the gummy/sticky bass port patch back on is harder than playing Operation. The patch appears to be be occlusive. You could tune with other materials. I wedged some cotton between the ports and yolk assembly and am pleased with the results with the K7XX pads. With the K701 pads, sounds best with the port left open.
     
  20. spoony

    spoony Spooky

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    I'm glad you found time to try it :), yeah, there a Iots of different mats, as long as it's not too closed or too open I fathom it would have a positive net effect on sound. I also tried making the center opening bigger but the improvement diminished considerably.
    I wasn't picking up the K7XX over my T50RP before the mod due to what I can only describe as a 'hollowness' to the sound, but the mat fixed that and took the pair almost to the point that I would call it an amazing listen (there's still a bit of work to be done at the higher frequencies and maybe bass tightness).

    My guess is you're treading closer to the Tor4 mod, haha, maybe his type of felt works better?

    Thanks for the insights, I will consider damping the back side if needed once I'm finished with the ear chamber, I have a measurement microphone coming and I will be capturing data as the mod progresses.
     

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