I'm selling these to get something that isolates a lot more.The purpose of the mod is to reduce the "reverberation" effect to sound more controlled. I put a fiberglass disc up against the rear grill and stuffed the earcup cavity with Twaron angel hair damping material. The stock damping is also inside.The result? Less reverb and more linear midrange. Less of an "earcup" effect. It is easily reversible - just remove the damping materials I put in and align the stock damping within the earcup cavity.I like to EQ, so I'll also share my EQ settings I used with them if you'd like. I'm using Peace GUI or EqualizerAPO.It's in excellent condition. I can't find any sorts of imperfections. Works perfectly.Comes with everything that it originally came with plus Microsuede pads which cost 50 USD new.From a smoke-less and pet-less home.Feel free to PM me any questions about the headphones!Measurements:The treble is not as scary as it looks. In my EQ, I have the treble top out around where 1 kHz would top out so that it sounds about right (to me).