ray
i don't think the detrimental effect of the bass would be that noticeable, but you won't know unless you try it out. I used a ladder and a tall CD stand to "place" my rear QS8's on 2 opposite corner walls. When I felt that it was acceptable, I went ahead and wall mounted w/ the QS8 brackets. I also used those channel guides to hide one of the QS8 wires because I had to come down from the ceiling. I got them at home depot and the look is acceptable.
You can also try some B-Tech brackets. I got a pair of them to possibly use and never even mounted them. The nice thing about the brackets is that it allows an "opening" at the bottom for the QS8 woofer. Take a look at:
http://www.btech-usa.com/bt15.html 
