Unbeknownst to many of you SDA freaks, someone has been working on finding the perfect surround solution to match your particular model of SDAs.
Example: this CPer lent me a pair of CRS+ to play with...a perfect match I thought (and I'm right) same, tweeter, driver 6510, SDA 6511 and vice versa with the 1Cs...great timbre match, when driven in SDA mode, huge rear soundstage.
While I was enjoying this wonderful upgrade, the mad tinker started working on something smaller. I have a mantle which can accomodate books and he thought the CRS's were too low. Next up, he modded some M4s, with a crossover mod, driver swap, but the same tweeter...Excellent, but just couldn't displace the same air as the SDAs or another surprise bonus, RTA 8ts (same driver and tweeter), but they sure could fit on the mantle.
Forward to last night...I told this guy he couldn't bring anymore speakers down and had to take some back...ok...but he had a surprise. My wife's away and she probably won't divorce me...maybe...so ok, you can bring a surprise down, but take away the other 3 pairs :p .
Since I had commented on the 4s not being "quite right" and the CRSs/RTA8s being "special", he took it as a challenge. What he brought were modded M5s, with the same SDA crossover imported from spare CRSs...lo and behold, they are perfect. Total timbre match, nearly the same bass, but mantle friendly (sort of). We listened to some MCH and watched 300...the modded M5s are every bit as good as either the CRSs or RTAs in the surround role...maybe better. The benefit...precise soundstage, timbre match, can handle 98% of most surround bass, smaller. The mantle is about 1' above the couch/ear level, so by flipping the speaker, the tweeter is right on for surrounds. The other speakers throw a huge soundstage, but the tweeter level being below ear level was noticeable once I got the 5s above it.
Payoff: The guy who did all this futzing around is still not finished. Last I heard, he was going to create some sort of di/bipole CRS combo, that would be small enough to fit in an ear bead( I was getting pretty tired).
Steve...Polk65...take a bow