pizzapro,

You may want to play with the SMS-1 or your crossovers on the 990 or your room acoustics. Wow, that's a few things to play with I know. I have Klipsch speakers (horn tweeters - considered quite bright by most) and the 990 sound absolutely incredible with 2-channel. With the SMS-1 you really have a lot of control with how well the bass and other channels integrate (one of the most important aspects of sound in my opinion). Out of curiosity, what are your crossovers set at? And how flat is your sub response as plotted by the SMS-1?

I listen to 80's rock and a lot of jazz such as Nora Jones, Sara Vaughn, big band, etc. and it all sounds really good. I prefer Upsample mode followed by Stereo, and don't really use bypass as the bass seems too heavy in that mode. I am left wondering if you need more power to drive your speakers and if that could be causing the harshness. Are you usually listening at higher volumes?