I understand what Peter is saying, but if you crank the master volume all the way during test tones and reduce the speaker trim to get you down to 75db, it would seem to me the only way to raise the speaker volume levels above 75db would be to individually adjust the trim on each speaker rather than using the master volume control since it was already calibrated to be maxed at 75db.

A computer once beat me at chess, but it was no match for me at kick boxing.