I'm currently using pill lsif/x as surrounds I bought a pair polks rti a7s to flip and wondered how they would compare as surrounds I know I could just set them up but just curious if there any serious reasons to wither do it or not
Use them.
For sh!ts and giggles I swapped my RBH bookshelf out of the side surround position with my old B&W 804M floor standers (planned to gift to son). That was 6 mos ago, the B&Ws are still handling the rear channels.
I wholeheartedly agree with post #3, multi-ch music delivers full range to the rear speakers thus your system is rewarded by having full range rear speakers.
Even some movies, the rear channel audio is more than just the cursory ambient sound effects. I just watched Everest on 4k disc and the rears get workout...I could see the RBHs struggling in a larger room to produce that same lifelike feeling of being on the mountain with the climbers.
Eventually my son will move out (hopefully) and once the B&Ws are gone I wouldn't go run out and upgrade my RBH book shelfs just to put larger speakers there, but at some point I can see having a pair of Murphy's BMRs for the rears.