My first impression of the H6, in a word.. shy. That's not necessarily a bad thing though. This afternoon I auditioned them at the Apple Store. Whoever listened to them before me put the EQ setting on Spoken Word. (Don't you hate that.. LOL) I disconnected the iPod Touch and connected my iPod Classic. The song I auditioned was "Wait for the Summer" by Shake Some Action! I thought for sure the H6 would either sound too bright and/or too thin. That wasn't the case however. The H6 reminded me of a hybrid between the AKG 701 (soundstage and bass quantity) and the Sennheiser HD 600 (detail).
At home I did a quick A/B with the H6 and the KEF M500. The KEF M500 sounded very bland almost entirely lacking treble. When I switched back to the H6, the M500 made the H6 sound thin and distant. I wasn't expecting the sound signature between the H6 and the M500 to be so different. During the last two hours of listening to a random mix of Indie Rock and Electronica on an iMac >> HeadRoom Ultra Desktop Amp, the sound signature of the H6 has grown on me big time. Two thumbs way up!!