Quick history: Have Grado RS-1 & RA-1, which I feel have an excellent balance of bass, mids, highs. Purchased MG Head, Senn HD-600 & took the advice of many of you and added Cardas cable. Question is - how can I expect the sound of these to change as time goes on? Right now the base of the Senn's is a bit to heavy, especially at higher volumes, and the highs don't have quite as much "flavor" as the Grado's. I tried this combo because the Grado's sound is to forward for my taste, and they just aren't comfortable enough for extended listening.