Mike, try hooking up a different source to your PWD to see if it is truly what introduced the brightness to your system or if it is simply the Sonos unfiltered that you are noticing. The stock Sonos has a lot of hash to it that can come across as being very bright.
If you don't have a decent CD transport, use your laptop via the USB (which I feel is a better connection than the Coax on the PWD) - a half decent cable from your local Best Buy is all you really need to see if it makes a difference. You can even download a hi-rez album or two from HD Tracks to hear full capabilities of the PWD. I like the Chesky collection myself.
Good luck.
If you don't have a decent CD transport, use your laptop via the USB (which I feel is a better connection than the Coax on the PWD) - a half decent cable from your local Best Buy is all you really need to see if it makes a difference. You can even download a hi-rez album or two from HD Tracks to hear full capabilities of the PWD. I like the Chesky collection myself.
Good luck.