Presently, I have a L/C/R and sub and want to add the QS8 to complete a 5.1 setup. My problem is that my room will not allow true side placement so I'll have to position the QS8's at about 20 degrees behind my listening position. My amp/receiver will permit connection of both rears and sides. Given that I want these to function in my 5.1 setup as well as certain music listening, is it better to connect the QS8 via the rear output or the side output on my amp/receiver? Does it matter?

Appreciate any advice.

20 degrees is more "on the side" than at the rear (unless I did not understand your point of reference). If your receiver allows you to electronically redirects the back and surround "on the fly" then it does not matter. If the connections are physical, you will probably be best using surrounds. Multichannel analog (SACD, DVD-Audio) are hardcoded 5.1 channels. So, again, I may have missed something in your points of reference, but I think you have less chance of running into problems using the surround outputs than the rear outputs.

So you have no options to mount them up higher, closer to the ceiling on the sides? If not, 20deg behind you would be fine along the side walls. You may be able to slide your seating back a bit also?

The Qs are best if about 2-6ft above your ears, but many, including myself, have them mounted near the ceiling as long as you allow room for the top driver.

For 5.1 you want to use the left/right surround terminals, not the rears. Even if your mounting the speakers on the back wall in 5.1, you would not use the rear jacks unless your using 7.1 Dolby PLIIx for instance where 2 channel or 5.1 gets matrixed to the rear speakers.

Tiger, welcome. You really don't have the option that you're proposing, but you don't need it. If you mean that your QS8 positioning would be about about 20 degrees farther back than directly to the side of the listening position, then that's just about ideal for the side surrounds in a 5.1 setup. They should be a little farther back to lend a little more rear surround effect in the absence of back speakers in a 7.1 setup.

Furthermore, most(all?)receivers don't permit back surrounds to operate when side surrounds are set to None. Even if it could be done, they would be sent different(and wrong)material than what they should be reproducing, and some sound intended for the sides would be lost.

To add to John's comments...