Interesting. I never used a SPL meter, but I do not mix (except subwoofers). I have 4 sets of home theater speakers. Kef Ref One, with Kef IQ9C center, Kef Q7 with another IQ9C (love the IQ9C and IMO sounds better than ref 90), B&W 600 series in bedroom, also a set of Paridigm Monitors, hardly...