Are people seriously suggesting him the HD-650 for electronic music and hip hop? I could understand classical and hip hop, but any kind of electronic music on the HD-650 would just make me sad..or fall asleep.
I do find the HD-650 incredibly boring with a lot of music. Sure I liked it, but only with specific music.
I've always preferred for electronic music a headphone with tons of detail, a decent amount of bass and a very clear sound. Yes, even a lot of treble (that isn't ear piercing). The HD-650 only meets one of those requirements.
Between the HD-598 and HD-650 I'd take the HD-598 for electronic music any day. Sure it has much less bass, but at least it won't bore you to death. It's mids are a little more forward than that of the HD-650, but no more "colored" than the HD-650 already is.
It won't suddenly change how a song sounds. The large soundstage of the HD-598 helps too. Despite what people say, I've found the HD-598 to have much more detail than the HD-650. Please don't give me the treble excuse..
I'd actually skip any of the Sennheisers for electronic music. For that I'd probably take the DT-880. The Q701 doesn't have tons of bass, but I'd easily take that for electronic music over the HD-650 any day.
Ambient music is especially impressive on the Q701.