I love the sound of my music on the HD650 but it's the farthest thing from a "blow you away" experience. In fact, at first it was the opposite. I thought surely some detail much be getting masked but then I compared the same music on my old headphone and the HD650 is revealing all sorts of subtleties the others miss. It just doesn't grab you with brightness or boominess or forward "presence" on vocals and featured instruments.
And for a headphone that's senstiive to detail, I find the HD650 very forgiving of old or poorly mastered recordings. It's because the '650 does not its own harsh "highlights" to the already edgy sound quality of some older sources. Yeah, they still sound like old tapes but it's very tolerable unlike with some headphones that really amp up the harshness.