You'll probably have HDMI from the cable box to the TV.

Depending on your receiver's possible inputs and the cable box's available outputs (optical, rca jacks, etc), have the audio output from the cable box go into your receiver, then the speakers get plugged in to the receiver.

I had been speaker hunting for several months, for in-wall speakers I recently settled upon Polk RC-85i's ($225 a pair) in the main room and RC-65i's ($150 a pair) in a couple of other smaller rooms.

I had not planned on Polks when I started shopping. And I'd never purchased from Crutchfield before this purchase. Crutchfield was having a special where if you spend over $450 you get a Polk PSW-111 subwoofer (about $300) for free. Not sure what the deal is with the subwoofer, I thought it might be reconditioned/returned or something like that, but when it arrived it came in new packaging, and an email from them said it was indeed new.

In-wall speakers can be a bit weak on bass, so a subwoofer isn't a bad idea. For placement, this Polk subwoofer can go pretty much anywhere in a room. Even behind furniture.

I had looked at several lines of in-wall speakers. Normally I'm a Klipsch guy, that's what I have for my stereo set-up and for my home theater. For the in-walls these are used primarly as background, whole-house music. So I wasn't looking for audiophile sound, but I was looking for a slightly bright, non-muddy sound. Something that sounded good at mid- to low-volumes, but at the same time a speaker that wouldn't break up at high volume levels.

While speaker preferences are quite subjective, I'm very happy with the Polk speakers.