I had a DT1990 which I ended up returning since it sometimes got physically painful to listen to them, particularly with poor source material, due to the huge treble peak(s). My HD600 as replacement arrived while ago and the experience with these has been way smoother and just better. Only thing I miss from the DT1990 is the disgustingly good bass response for open back phones, but overall I'm very very happy with the HD600's so far.