I put a Watt meter in between the wall socket and the amp.
once a movie or music CD is ended, i check the maximum wattage indicated on the watt meter, multiply it by 0.7 and this gives me the approximate # of Watts that were sent to both front channels; i then divide this number by 2 to get Watts/channel. (The QSC amps are about 70% efficient).
this is not precise in any way, but it does give me an idea about what's going on, power wise.
the best instrument for this would be a peak hold function on an oscilloscope.
when i want to know the movie's max SPL at my MLP, i put an SPL meter on the nearby armrest with the meter set to "peak hold" and "Fast".
this is quite precise, as the meter has an accuracy of +-1 dB and is user calibrated; Freq. Resp. is 20-12 500 Hz, and readings are taken with the Flat "curve".
The flat curve takes into consideration bass frequencies without attenuating them, like C weighting does. it shows the real bass level, in a linear manner.
one must never forget that instantaneous power peaks can be 10-20 dB higher that the average or RMS value. this is very important because caring only for average levels will mean peaks will be clipped.
most of the time, very high power demands last only small fractions of a second and as long as there is no distortion (clipping) in these instantaneous signals, one is not aware of them.
the more those peaks are cut off, the more distortion that can be heard.
of course, this does not apply to highly compressed music.
Last edited by J. B.; 09/05/12 01:33 PM.
