Let´s collect all the Sony MDR-7506 Mods under one topic. What i have found, is at least Earpad mod and cable mod. i personally have not tried those, so someone else could contribute on those. But what i did, was something that goes a bit further and deeper to fix some issues in sound quality that i found with these one. I had own couple pairs of them over last 20 years, or so. And they are good even as todays standards. Very good indeed. No wonder they become some kind of industry standard, among sound technicians and field recordist. But there is couple on issues with tonal quality, that keeps them off to be so called Hi-Fi, to my taste. One is lack of deepest bass and another is, that they are a bit harsh at upper mids. That resonance is very annoying especially with some female vocalists, and brass instruments So lately i have been modding my Grados, like a mother...´s boy and extremely positive results from there, made me think, that could i use those methods on these one? So i popped my Sonys open (Take off ear pads, and you find four crews. It´s that simple) Right away i found that grill that protects the driver, is thin metal. And that metal rings like a bell, when you tap it! So i damped that with dynamat. And as i was on it, i put some of that inside of ear cups too, to damp any vibrations and possible colorations. Make sure, that you don't put that alumine coating in the middle of cup. That could shortcut the driver. Next we need to pump up the bass! Backside off the driver, there is this paper/felt ring, that covers all but one hole. Those holes controls the amount of air that flows thru the driver, and that affects bass response. So i opened one, and got just more enough subs, to my taste. If you gravy for more bass, just try to open more. You can always use similar kind of fabric and fill those holes, if you over do it. But i recommend that you pop one at the time, and listen. I must say that i was a bit suprised how well this did work out. It did just what i was after. Upper mids are no longer fatiguing and there is that extra deepness in bass, that was lacking. And that bass is sooo tight! I think it´s a bit tighter, than in my heavily modded Grado SR325:s. Damned!!! in a matter fact i might like these now even a bit more, than my NAD viso50:s!!! In a word, they sound amazing! One of the best sounding closed headphones, i have ever heard, and i have heard plethora. And it took me around 15min to make this mod. Like wice man from Greece once said: Just do it!