Ok so I have a new in box 220 and my one with 100+ hours on it so let's see how important this burn in stuff really is. I'll also compare it to the brainwavz pleather memory foam pad without any mods.
Started with the old fio x3 but it was adding a cludge to things that wasn't helping the already congested midrange and the treble is a bit lifeless sounding, someone earlier in the thread said something to the effect of "someone playing violin in a graveyard" and that makes sense to me as I'm listening. I remember them sounding better....perhaps they're not burned in enough?! They sound better with the x3-2, more balanced but less bass heft.
Stock: Good impact on the double bass some obvious congestion in the midrange treble is washed out and dead sounding, but frequency response is even and the recording is presented accurately though without the level of impact and texture it could. Perfectly listenable stuff but it's hard to take seriously when a changed pad makes such a dramatic difference. Sounded the same to me.
Pleather: Awww yea. The congestion is gone the bass heft is more impact is better treble is clearer, it's like I was listening to a walky talky before. HOWEVER these pads are much more sensitive to positioning than the stock pads. Tilting them back too much will mess with the sound, you wanna keep em generally centered and over the the middle of your ear. Alternatively you can move em around for some natural eq.
Stock:I don't think anything can make this sound bad. It's basically just one high frequency instrument after another. The congestion is there but it's less noticeable than before. Horns sounding pretty sweet. Went back and forth thinking I'd heard a difference but would then find I didn't.
Pleather: Ya same story, it just, sounds better. You know? Getting some good soundstage out of this actually, but it's pretty vaguely defined, hard to place. Horns sound even more sweet.
Stock: This one's really deflated sounding too some of the trebly stuff sounds good tho. I went back and forth to see if I heard a difference, I don't believe I did.
Pleather: Hmm this sounds way better obviously but still kinda flat, not as sharp as I know it...lemme try the old x3. Ya that's more like it, honestly prefer the old one for the pleather by a lot, but that's not how a comparison works!
There are inevitably deviations between headphones and even the drivers of the headphone in the treble range specifically, so maybe I did hear something. But whether that something was burn in or manufacturing difference, it was crazy small even when I was specifically looking for it. It would disappear on second inspection and would never be apparent in normal listening. I don't see any reason not to just immediately start listening to this headphone, just let your brain adjust to the sound signature, hopefully without those stocks pads