No, just one mic location for ARC. Then I use multiple mic locations with Dirac. I don't see an upside to multiple locations for the mic with ARC and Dirac.
So I use 1 mic setup for ARC only at the MLP, then use multiple mic setups for Dirac. The mic doesn't move after running ARC so I can go right into running Dirac starting with that mic location first.
If I wasn't using Dirac, then I would use multiple mic locations for ARC. There can be compelling arguments for using 1, 3, or more mic locations, but if only one person is listening to music, is more than one mic location necessary? Not for my setup. But if more than one person will be listening, and the user wants more than one person to have a "better" experience, then use more mic locations, but this can mean a compromised experience for some seating positions because - it's a compromise - within a range of response over a range of seating positions. It "can" be that, or it "can" be ok, depends on the room, layout, treatments, etc. I'm pointing this out because I stopped going nuts with lots of mic locations after many correction runs and learning how my room works. For example, I know there's a null above ear level and to the left of the seat left of MLP, so I avoid that spot because nobody is listening with their ears up there and that null doesn't affect anything so long as I don't measure it. But if I measured it then the correction apps want to "fix" something that really doesn't need fixing. So I only measure where ears are listening.
The best advice I know of is that if the mic cannot see the speaker, then it can only measure reflections. So the mic must always have a clear view of the speaker. In the case of measuring 7.1 setups with Dirac, and the seating has high backs, then the mic locations Dirac recommends using behind the seating below ear level simply do not work, the mic cannot see the front speakers. Common sense must prevail. Try it, check it, use what works for your room setup. Start simple, then go bigger. Buy low, sell high
