Originally Posted By: taym
I already tried 3 high-end sennheizer and 1 high-end Sony. No significant improvement.

What was their impedance, though? If it was the same, then that wouldn't improve the volume issue. Of course, I doubt that a new pair of headphones will significantly improve an audio quality problem that people have apparently tested empirically (I'm taking you at your word on that), but it should increase the volume.
_________________________
Bitt Faulk