AKG K701s are not difficult to drive - 64 ohm is not that much - but they leak sound so bad, I don't think I'd ever recommend anyone using those in an office (u

AKG K701s are not difficult to drive - 64 ohm is not that much - but they leak sound so bad, I don't think I'd ever recommend anyone using those in an office (unless you want to hear everything around you or listen to music at deafening volume in which case everyone around you is forced to listen to it as well).