Of the speakers I have the QS8s are the best height speakers. I’m not sure if it would matter if you had M80s, M60s or M50s. However I imagine that the QS4s would do fine because the height speakers don’t really have to do very much.
All that comes out of them are ambient sounds like wind, rain and echoes. There are no direct sound effects or hard pans from other speakers. I imagine someone could even mix bi/di-pole speakers from different brands and it would work fine.
Audyssey does recommend direct radiating speakers for height and all other positions for that matter. Not sure of Dolby’s position on it. But like I said above speakers that spread out the sound like bi/di-pole work better for me since those are the types of sounds coming out.
