I asked Chris (Audyssey) via PM on AVSforum what he thought about using a Dipole Speaker for Heights....waiting on feedback.
Unless something has changed he will say to use direct radiating speakers for all positions as is the Audyssey standard. Their EQ algorithms don’t always play nice with mult-polar speakers so if your goal is prioritize Audyssey then don’t use multi-polar speakers anywhere even as surround or rear speakers. If your priority is to get the best sound from your system then listen to the various types of speakers in each position you are concerned about and decide for yourself what sounds best to you in your room based on price vs performance.
Buying speakers to match an EQ system is in the opinion of most people, except the makers of EQ systems, backwards. Buy the best speaker you like for the application and only after proper placement and possibly treatment then apply EQ.
In my experience EQ only works well below about 200Hz but YMMV.
Timbre matching the wide and mains as I mentioned above is critical since they share much of the same sonic information. The M2, M22 and M80 are a perfect timbre match to each other when the M22 and M2 are crossed over at 80Hz or above.
Timbre matching the height speakers may not be as important since they don’t share as much audio information with the mains and are generally placed farther away than the wides both of which reduce the need for perfect timbre matching. Still would be ideal to timbre match but mixing a different brand is doable if not to different sounding. Just as many people run QS8 surrounds with other brands of front speakers. IMO timbre matching surrounds is more important than heights because of the direct pans often handed off between the mains and surrounds.
