Not sure. Why would the mixer set one lot of speakers 3dB below the others? Post calibration all the speakers should read the same SPL. Most room EQ systems will set them pretty accurately IME.No I was referring to making sure that your speakers post cal are indeed capable of playing at the same SPL based on the level set, with bass management and room EQ enabled, before we play actual content.
Meaning that if a mixer tends to, for example, have the top middles 3 db below, say, the top fronts, but the levels for the top middles were set by an Audyssey or other room EQ another -3 db below the top fronts when you test the speakers using pink noise and an SPL meter with bass management on (using whatever method you have to play pink noise with room EQ and bass management on), you’re actually not fully capturing how the soundfield is supposed to sound. At least as “reference”.
So I was agreeing with your point about speaker levels with Atmos. Make sense?