Appreciate your comments and those of others on this thread, but most
comments seem to focus on the definition of RMS, not the basic issue of
misrepresenting power output capabilities of modern amplifiers. What I
recall from the late seventies is that the International Institute of High
Fidelity (IIHF) had established detailed technical specifications that
defined the measurement techniques that would necessarily be used to
establish the specified amplifier power output on an RMS, continuous power
basis. This specification process was, as I recall, very rigorously
described.

What happened to IIHF? Is there no accepted industry standard, either in
Europe or North America or elsewhere on rating audio amplifier output power
levels?

"Ian Iveson" wrote in message
. uk...
Roderick said

RMS values of the current and voltage are used to calculate the mean (or
average) value of the power, because these values of voltage and current
are
equivalent to the DC values that would supply energy at the same rate, so
"mean
power level" is the quantity that should really be specified.

Yes. If you square the root of the mean square you obviously get the mean
square. Since the square is proportional to power, you get mean power.

There is real and meaningful confusion in this RMS power nonsense. Pure
inductors and capacitors dissipate no power, although they may have
voltage across them, and current through them, simultaneously. This is
possible because positive and negative power cancels. RMS power would not
cancel, because it would always be positive. Hence it is not a trivial
confusion. It is indicative of a serious lack of understanding of basic
essentials.

My first question in the hifi shop is always "what kind of power is that?"
If man says "RMS" I walk out. Hence I now have to make all my own hifi.

cheers, Ian