AFAIK room correction can only really work in one 'sweet spot', or more sophisticated versions can do some averaged compensation based on several measurement points. As colonel, jagwap and bigshot have alluded to, room correcting DSP can only control the sound until it leaves the loudspeaker, and typically this is just done with phase, time, and EQ correction. If you have control at the individual driver level the way Sonos does, you can do a bit better, but it still doesn't actually "correct" the room. It allows the speaker to compensate for the room a bit. Space still dominates! So in the basic systems with one mic and just simple time/EQ correction, you'll fix a lot of peaks and nulls at the exact location you place the mic. The rest of the room is anyone's guess, could be worse, could be improved. Edit: Back on the actual topic of the thread. I just got a bunch of brand-new, ostensibly identical samples of headphones straight from the factory. I will leave one running pink noise overnight and let you guys know if I hear any serious differences in the morning. I don't have proper measurement gear here so it will by ear, so only really blatant changes are on the table here.