I plugged mine into an iPhone and didn't particularly notice a "bassy" sound. Actually, after reading the reviews I was more struck by how un-bassy they sounded. I don't have much experience with the M80 so I can't comment, but I thought the MOMENTUM was clearly a Sennheiser headphone. ( if that...
Same here. I really wanted to love these headphones, but alas, the cup size made them just too uncomfortable. Sold mine and went with the HD650; I have no complaints in the end.
Interesting. I sold my HD800 because I had trouble listening to Natalie Dessay (my favorite soprano) recordings with them. It seemed disembodied and unnatural, and the sung S's were just odd.