Yeah, I'm ashamed to hear people here recommending such options for your setup! In all good consciousness, as someone who's got such quality speakers, otherwise, as Avantgardes, I couldn't recommend another THIRD BRAND of speakers to ANY setup!!! This is a major NO NO for keeping the sonic integrity of your soundstage coherent!
For instance, let's simply move around your sound system, with say your proposed scheme: First, a sound moves from your left front speaker (Avantgarde) on to your center speakers (Martin Logan), then on to the right front speaker (Avantgarde again), then over to some OTHER BRAND of speakers, and then back around to your Avantgardes!!!
This is NOT HOW YOU PUT A QUALITY SYSTEM TOGETHER! I mean, you wouldn't have 2 different brands of left and right front speakers. So why would you consider doing what you're doing, and expect quality?!- cause you won't get it.
You'd be WAY better off either dumping your Martin Logan center, in exchange for and Avantgard Solo(I think that's what it's called) - and maybe adding Solo's in rear - or simply forgoing a center all-togther, and just running stereo! (yes, you could do Avantgardes all across the front, and MAYBE fudge with some other horn-like rears. But it wouldn't likely be so stellar. Remember, quality over quantity! (more is NOT BETTER, necessarily)
Your other option is to simply stick with you Avantgardes for L/R dubty stereo, and add some quality on-wall MATCHING surround system, yes!!! This would give you quality all around. What you're trying to do now will NEVER yield anything but a hodge-podge of sound from your system. You'll always be simply listening to "gear", and not be able to get a soundstage that dissapears into the room! It's your choice.
If it were me, I'd STRONGLY CONSIDER either simply sticking with the 2 channel setup for both music and/or movies, or just getting another system for your multi-channel dubties. This will likely give you better off-axis seating, and a large sweetspot, and also a coherent sound from your system! Yes, you're doing it wrong. If you think not, simply direct your question to ANY AUDIO MAGAZINE PROFESSIONAL REVIEWER, and see what they say! I garatee they'll concure.
Either way, you can do what you want. The Avantgardes fall off like a rock with off-axis listening - which is why you want multiple speakers all around the room anyway- and theyonly have a narrow listening window, if being a superb dynamic speaker system, otherwise.
Yeah, Avantgard Uno's up front for stereo 2 channel dubties, then some sort of On-wall mounted speakers for 5 or 7.1 (or more) movie dubties, INDEED! That's the correct way for you,IMO. Good luck.
