OK, now you understand how it all works. Good show !
1. Yes, if the sub's crossover is lower than the receiver crossover and you are letting the receiver crossover control what goes to the mains (and other speakers) then you will get a hole.
2. If you use the speaker-level connections for the sub then the sub would only get LF signals originally intended for mains -- LFE, plus low notes from center and surround channels would be lost.
However, there is a trick -- some receivers will automatically send LFE plus the stripped off low notes from center and surround to the mains if you tell the receiver you don't have a sub AND that your mains are "Large". In that case the mains (and hence the sub) would get LF signals below 120 Hz from all of the channels. The M22s would handle down to their rolloff, and the sub would start to pick up as the M22s roll off.
The quality of the resulting system would depend on how the rolloff of the sub and the M22s matched up... AFAIK M22s are fairly easy to match with a sub.
Personally, if your receiver had a 120 Hz crossover I would stay with the simple approach -- just run the M22s in Small, hook the sub up via Subwoofer Out, put the sub "not too far from the TV" to avoid blatant localization problems, and be happy. You are asking all the right questions and could spend an enjoyable day playing with the different combinations but probably not worth it. Either way, find out if the receiver will send LF (LFE + stripped from center, surrounds) to the mains when you have no sub -- without that, don't even try.
If the crossover were higher than 120 Hz the approach you suggested would be more attractive.
EDIT - re: the QS4s, I wouldn't worry too much -- it's the tweeters on top and bottom that IMO have the most effect, and those will work fine even without a back wall. You could try hanging the QS4s from the ceiling behind you with FMBs or angling them a bit forward but personally I think the side wall position will still be best. Slightly above and behind you, right ?
re: any escape might... I was wondering if "powerwindow" was a Rush reference... but then again I live in Toronto so...
Last edited by bridgman; 07/01/05 06:42 PM.
