About two months ago I bought an entire Polk system including a DSW Pro 660wi.
It is directly connected to a Marantz SR7005 (via the RCA Subwoofer out).
My issue is that the 660 likes to go to sleep during the middle of movies. It's quite irritating. In Avatar (Blu-Ray, Samsung player), I there is a scene I can play and without fail, within a 5 second or so timeslice the 660w goes to sleep. It also tends to go to sleep on PPV and AppleTV when the volume is around -1db but not when the volume is lower.
I am unable to figure out if it is overheating, because simply unplugging the 660wi and plugging it back in will turn it back on and it will run for hours again without going to sleep.