I am trying out the AKG K712. Initially I was very disappointed as it sounded thin and insubstantial in comparison to the HD598 and Grado 325e that I have, but I made the mistake of trying directly from an iPhone. Then I remembered comments that this would not allow the 712 to realize its full potential. It didn't sound bad though, but I had to raise volume up to almost 100% to get it to sound decent. I hooked it up to the O2 amp that I have and it is much better. They have a nice sound signature. I don't necessarily find them "warm" as most to people do - the bass seems a bit toned down even compared to the HD598 - but they are smooth and detailed. I am not sure I believe in the whole "break in" thing and whether that would accentuate the bass some more. Interested in hearing thoughts on that. They are very comfortable and light though, and that's a huge plus for me. I also like the coiled cable that comes with it too. Time will tell whether I decide to keep them....