Figured I may as well chime in with my newbie efforts here. I picked up the T50rp but the silverstone and 840 pads are on backorder for a week or two it seems, so I started tinkering without them. Well, first I gave the stock cans an evening to familiarize myself with, and my impressions about them are the same as everyone else and their mom's: totally luscious mids, rolled off lows and highs, hugely dark presentation. Responsive, nice imaging and decent soundstage, which I wasn't expecting from mostly closed phones.
I should have given myself longer to acquaint myself with the stock sound, since this was the only time I was going to be able to listen to 'A' in the A/B B/C C/D etcs that I knew would ensue... but screw it, after a couple hours I went to town with the screwdrivers and never looked back.
What followed was a flurry of irresponsible and mostly futile modding attempts using pretty much anything I had lying around the house. Versions went like this:
v1: +plasticine damped baffles, +4-ply drier sheet square over driver w/ stock white felt intact
v2: 4-ply sheets pared down to 2-ply, +plastic reflex square over middle driver square,
+4mm cardboard cookie on top of drier sheets, +1/4 in. low density memory foam on back of earcups
v3: -drier sheets on driver, -reflex square, cookie only thing left on driver, -memory foam from cup backs, +8-ply drier sheeting on backs and walls of cups
v4: -cardboard cookie, +1 teased cotton ball per ear cup
v5: -drier sheeting from back of cups, -cotton from cups, only plasticine damping is left
Starting with v1 and ensuing pretty much all the way through the experiments, the
only change from stock was a significant bump in the 7-9ish khz range, fairly tinny and sibilant and not fun at all to hear crop up. I thought this most probably had something to do with the various dingums I was gluing to the driver and kept fiddling with them trying to find a happy medium between stock and v1 peakishness, but it never diminished.
Really the only modification that persisted throughout was the plasticine-loaded baffles... I'd thought the mass loading was to stabilize the driver and tighten up the bass, not anything to do with the treble? Is it conceivable it'd bring the highs so much forward like that?
Overall I'm pretty sore about the lack of variation I heard between the mods but I did jump into the little stuff before doing the two biggest things I could have done (pads and acoustic foam). I'll have to dig back into this project after the rest of the goods are delivered.