I think the problem is from from your pair or from your particular feel of the dt770 sound signature. Another headphone (if the problem is not from your hearing) should solve the issue. Maybe open back headphones with better soundstage are the solution. I have no experience with the 990. Do u have any other headphones to compare? Also if some cheaper(lower impedance) headphones work ok the problem may be related to the need of an amp.
1/18/14 at 9:01pm