andrze,
i bought Greg's DT831 home yesterday, only to find them overly bright. painfully bright. yank them off my head as fast as i can bright. switching from my Technics SUV96 to my Crown D60 helped a lot (better impedance matching, greater damping). but what really helped tame the highs was switching from my Apex DVD player to a Denon 810 CD player. I will be getting an Oknyo DV-S555 dvd player which I will compare to Matt's and Greg's sacd players (using regular cds). hopefully the onkyo will open up the sound up more (burr-brown dacs).
so yes, they are bright. but i prefer that to rolled off highs which have no timbre, no delicacy, no sweetness, no smoothness, etc. as I am used to open headphones, the perceived lack of bass doesn't bother me. with the right sources, i think that the dt831 sound very nice. I've heard them trough a Melos, a SAC and a Porta Corda. They always seem to impress. and if you looked at the frequency response curve of the dt831 you would never even consider it. but if you compared them side by side with other headphones (as Greg, RVD and I are doing), you may come to a different conclusion. and like you, i can't wait to audition the dt880s. what bother's me is Jan's first impression that they are not as fast as the dt831s. i'll have to listen for decay of certain instruments. violins better sound sweet on them babies.
i wonder what you dt770 owners are using for amps. as Snufkin says, though, always trust your ears, as you did, andrze.
Snufkin, what cans allow you to air guitar? that must be some sweet midrange to play acoustic guitar so fine. the K1000 does that for me. i loved the AD10 for acoustic guitar - but it had lousy vocals.
