Thanks for all the replies.
kcarlile reminded me that I had forgotten to adjust the distance setting for the amp in my new space. That helped a bunch.
Also, I decided to do a test based on alan's post. I unplugged the fronts and the surrounds and plugged the surrounds into the front outputs. That also reduced more of the hiss, leading me to believe that the receiver has some limitations in the back channels. When I got home, I checked the model number and found it was the older vsx-1015tx, not the vsx-1015txk.
The speakers are only about 6 feet to my right and left, so not very far at all. It's a pretty small room.
Anyway, the hiss is mostly gone unless I jack the volume way up (which I do, sometimes), so I'll probably just deal with it for now. Although I would happily take any more suggestions, if there is anything else worth trying.
Thanks!
