HD650 sounded overall leaner and less warm/bassy than the K712. It sounded sort of like a more refined X1, but slightly warmer, a much more obvious midrange focus, a smaller soundstage, and lacking the "fun" bass boost and hint-of-treble-sparkle traits (so "n" shaped in comaparison). So yeah, kinda of boring IMO.
I tend to find "n" shaped headphones a little boring (same with HD5xx).
Edited by chicolom - 1/10/14 at 2:19am