I am using the HD700 now and I listen to classical music. Unfortunately, I am using a different setup from yours which consist of: Cambridge Audio DAC Magic, Objective 2 Amplifier and FLAC.
However, with my setup, I find the HD700 to be:
1. Good mids and highs.
2. Bass wise, I can't comment much because I am not a bass head. But the bass is ok enough for me, it doesn't degrade the quality of my Beethoven's recording.
i love my hd700!