Quote:
PS RMS is an acronym for "root mean squared", where the exact output of the amplifier is recorded across a range of inputed signals and then there square root is applied to the results, then the mean average is taken and that mean average is then squared.

Err, the other way around, I am affraid: first square, then mean, then root. That way you avoid those pesky complex numbers.

Actually, in the context of amplifiers, it is continuous power calculated from measuring RMS voltage while driving resistive load with harmonic (sinusoidal) signal (for prescribed time with prescribed maximal distortion etc). You could measure peak voltage as well (as long as you know the shape of the signal), but the life is easier with the voltmeter that gives RMS (or effective) voltage.