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The Audio Technica AD900 Bass Mod

post #1 of 10
Thread Starter 

DISCLAMER: I'm not responsible for any damages you do to your headphones if you attempt this mod. It's your fault for screwing it up, not mine. If you don't think you can do it, and/or don't have a steady hand, then don't attempt this modification. If you do, then prepare to be rewarded. Your warranty will be voided if you attempt the optional step in the procedure. 


Why the ATH-ADxxxx series doesn't have a lot of bass (Click to show)


  • Little to no headphone clamp
  • Horrible earpads that don't seal around your ears



What this mod does: (Click to show)


  • Significantly increases bass impact/quantity/SPL
  • Increases warmth, and adds much more body to the rest of the frequencies
  • The extra low end that you get really ties things together, making the music sound more immersive and proper. 
  • The soundstage sounds more complete. 
  • Slightly increases isolation
  • Increases headphone clamp 
  • Gives you a much better seal



Downsides of this mod: (Click to show)

You will lose some of the "airiness" that the AD series is known for. To tell you what I mean by that, get a pair of headphones that seal relatively well and put them on. Get used to the sound for a while, and pull apart the headphones so that they're a couple mm away from touching your skin. You should find out that there seems to be more extension and resolution in the upper midrange. That sparkle is what the AD series is able to replicate because the earpads don't seal very well, and there is very little clamp. That gives the upper frequencies have some room to stretch out their legs.


Materials needed: (Click to show)


  • Better earpads that seal around your ears (Preferably the Beyerdynamic Gel earpads. The W5000 pads may work). This will offer the most noticeable change in bass quantity.
  • Cotton balls
  • Clay (or something like dynamat). Get the type of clay that you get at arts & crafts stores. They're shaped like little rectangles. This is because that type doesn't dry out. 
  • X-Acto knife
  • Tweezers 
  • Packing tape (if you choose earpads that don't fit these headphones)
  • Small philips head screwdriver (for taking the headphones apart)
  • Vise-Grips or equivalent 



Some more information: (Click to show)

I did this modification on the AD900. This should work on the AD1000/2000/ADx series. I'm not sure of the AD700, or any of the models that use 45mm drivers, will work on this mod. The different enclosure designs may lead to a slightly different procedure. The beyerdynamic earpads are smaller than these headphones (AD900 and up). They are able to fit right inside the actual enclosure (pics below will better describe it).


Procedure: (Click to show)


  • Unscrew the 4 screws holding the driver frame in place
  • Take off the earpads
  • Take off the grill
  • [OPTIONAL] Use your X-Acto knife and cut the felt material around the driver. These are where the small holes are at around the back of the driver. DO NOT cut the felt material in the center of the voice coil (the magnet). It doesn't do anything to the sound (trust me, I've tried it). Be careful of how deep you cut. Push in the knife too deep, and you just destroyed your driver. Use the tweezers to help in removing the felt from each little hole. Unless you want the most bass possible, I'd advise you not do this part because it will void your warranty, and it has some side affects that some people may not be able to tolerate. 


            What this does is it allows the air to move more freely from the diaphram membrane through the ports. This will increase bass impact, slightly increase the midrange, slightly increase separation, and give you a slightly more open sound. Even though I say slightly, the change is noticeable before and after. The downside to this step in the procedure is that they will generate so much pressure that the diaphragm membrane will give off a popping sound. This is only when you are at loud volumes, you're playing a bassy song, you have everything on your rig maxed out in the bass department, and the headphones aren't on your head. The diaphragm membrane will now be reliant on the seal on the earpads to generate the backpressure necessary to keep it from making the popping sound. This is because there now isn't anything behind the driver restricting it from over-fluctuating. Like I said, this is purely optional. If you don't want to take the risk, you don't like the byproduct of this step, and/or you want to keep your warranty, then, by all means, skip this step. 


UPDATE: Do not do this step. I blew my left channel because of this. It over fluctuated, and it blew. 


  • Take off a small chunk of clay and stick it to the voice coil (magnet). This will help absorb any vibrations from the driver, thus giving you a cleaner sound. 
  • Put on the earpads. If you chose the W5000 pads, then you can skip the next step. 
  • [For non W5000 pads]

            For beyerdynamic earpads: Get your packing tape and cut off a strip so that you have it stuck to the outer driver frame. Make sure that the tape covers the circumference of the driver frame. Make sure you fold over the excess from the rear of the driver inside it. Place the earpads inside the tape ring you made and mash the tape on the pads so it will stick to them. Use your X-Acto knife and make small incisions where you need to put the screws in. You will have to do some modifications to the left side of the headphone because the cable will be in the way. 


            For earpads larger than the AD series: It'll be kinda tricky, but get your packing tape and wrap it around the earpads first. Then, place the pads on the driver frame, fold the excess tape underneath, and make the incisions for the screws. You will have to do some modifications to the left side of the headphone because the cable will be in the way.   

  • Get some cotton/tissue and stuff it underneath the earpads. This will increase bass impact, make the bass sound deeper, give you a better seal, and help with increasing headphone clamp. It also increases the soundstage a bit. 
  • Get some cotton balls and stuff it around the driver area (where felt material is all around the driver). It doesn't do anything to the sound, but I just wanted to fill it in for any .01% sonic changes...Plus, it covers up the tape behind there. 
  • Screw everything together.
  • [This part will require some time to get it right] Bend the headband so that you get a tight clamp. I'd advise bending the center of the headband, and the extreme left and right (where the metal wire go inside the plastic) sides. Use the Vise-Grips/equivalent to help aid in bending the wire. You can also throw the headphones in the freezer for a while so that the headband is more pliable. Just take the clay off if you do. Try to make the bends look pretty centered. You don't want to have a funky looking headband. This may void your warranty, but I don't think AT would care that much if you did this because they replace that part anyways. You'll want to bend the headband so that you get the best clamp and seal possible around your ears. If you don't have a good clamp, the bass will sound very flabby and loose, kind of like how is sounds when the headphones are stock. 
  • Enjoy. 




Pics (Click to show)


This was what I meant by folding the tape underneath it. 


Stuff cotton/tissue underneath the pads. 


Poor man's dynamat. It does the trick, though. All of those little holes had black felt material covering them. Use your blade to cut it out, and pull the felt out with small tweezers. 


Put cotton around the grill and mash it all together when assembling the headphone. 


Make incisions in the tape to put the screws in. It will be a bit tougher to screw in because of the tape and the cotton being inbetween. 


Whoops, just turn your monitor upside down to see it correctly. Note the angled bend near the base of the cable. 


Here's a better shot of the center of the band. It's a bit off center, but it's close enough, and it works. 



On the Battle Of The Flagship review, DavidMahler labled these as the "Classical Master". Red Bull gives you wings too...


If you guys are aware of the Pro700MKII (one of the best basshead cans when amped properly), these outclass them in every aspect. I shall call them the AD900MKII Mwahahaha....ha

Edited by Trae - 1/27/13 at 9:21pm
post #2 of 10

Nice mod. Bass wise, it would be nearly perfect to raise the 10-50hz region a bit, but the 'air' is oh-so-sweet... Are you aware of any ear-pads that fit these without modification?

post #3 of 10
Thread Starter 

Possibly AT's audiophile lineup of headphones. Since the angling system is awkward with the AD900 (the plastic around the rear of the headphone is elevated and the front recessed), some of the headphones can be scratched out. Which ones, I'm not sure. AKG's earpads may fit (the earpad size looks similar), but it will require modification. 


This mod doesn't just raise the 1-50hz region "a bit", it very noticeably increases the whole bottom end, which was originally rolled off because of the earpads and clamp. 

post #4 of 10

I'm surprised this hasn't got more attention. Very intrigued as I'm looking for an open headphone that does bass + natural sound properly. I'm a little scared at the DiY though. Not very confident. Plus it's going to cose quite a bit and if anything goes wrong I'll be at a big loss. The earpads aren't readily available and the nobody is selling the ad900 on ebay at the moment.


Does the bass really improve as much as you say? without the drawbacks?

post #5 of 10
Interesting, I would try this out but I don't want to wreck my headphones just in case. In Foobar I have my EQ 50hz, 63hz and 80hz at +6db and 100hz at +4db and it sounds beautiful. It takes it from barely bassy to decently bassy.
post #6 of 10
Thread Starter 
Originally Posted by RayleighSilvers View Post

I'm surprised this hasn't got more attention. Very intrigued as I'm looking for an open headphone that does bass + natural sound properly. I'm a little scared at the DiY though. Not very confident. Plus it's going to cose quite a bit and if anything goes wrong I'll be at a big loss. The earpads aren't readily available and the nobody is selling the ad900 on ebay at the moment.


Does the bass really improve as much as you say? without the drawbacks?

All you really have to do is put on better sealing earpads, stuff cotton underneath it, and bend the headband so that you get a good seal around your ears. It's actually a pretty easy mod, with the hardest part being the headband. 


The improvement in the lower frequencies is very noticeable. For me, it's all-round improvement, minus losing a bit of the airiness of the sound. Heck, I even think the soundstage is better than stock (more depth). I'll put it to you this way. People usually say that open headphones have little bass, while closed headphones do. This mod completely debunks that myth. 


I will say, though, that YMMV by what types of earpads you use. The thicker, the better (TWSS). The reason being is because you will have to bend the headband less in order to get the achieved clamp, and the thicker earpads will improve comfort (ears won't be touching the grill), bass, and soundstage. It may recess the midrange a bit (it just sounds farther away from your ears). The main reason why I have cotton underneath my earpads is because my ears would be touching the drivers (especially since I did this mod to these headphones), and because I would have to bend the headband too much in order to get the clamp I need (it would look more like a triangle). 


If you screw up the headband, you can always ask audio technica support to mail you out some replacements, or ship them out so they can replace them. 

Edited by Trae - 3/8/13 at 7:09am
post #7 of 10
Do you know anywhere where it's possible to get them from Europe? I've found them from b&h and beyerdynamics north american website, but the shipping ends up being as expensive as the product itself. I've found some gel ear pads for aviator headsets available from stores in Europe, but really can't find anything more than that.
post #8 of 10
Thread Starter 

I can't find them anywhere except for the sites you listed.

post #9 of 10

would u say, with the cotton/felt on the grills...it becomes a semi/open or de facto closed can? L3000.gif

post #10 of 10
Thread Starter 

It's an open headphone. The felt material behind the grill is purely cosmetic, and it does nothing to the soundstaging and whatnot. The same thing goes for the cotton I put around the driver.There may be a measurable difference if I were to take the cotton and felt out, but it wouldn't be noticeable to the human ear. 

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