I don't think that's the case at all, cgolf. A system calibrated such that all speakers are playing at 75dB loudness when the master volume is at, say -25dB, will use the same amount of power as the system calibrated to 75dB with the master at, say -18dB. The trim settings make up the difference. Whether you like to set your master low and boost the trims or set your master high and cut the trims is a matter of preference. The amount of headroom is determined by the efficiency of the speaker. A more efficient design will be able to take advantage of the headroom better than a less efficient type.
