Then I realized I had somehow lowered the master volume to -7 from 0.

Applejelly when I had this occur once I realized while in Speaker calibration I had jumped to using the ‘main’ volume controls on the 950 remote. (Upper ¼ right quadrant) as opposed to the < > buttons at SEL/PLAY to move dB while in speaker calibration. This will screw up your levels and confuse for a sec, when you go round the horn again for a recheck of test tones.