Cursitor Doom wrote:


This subject continues to severely bug me. I've just read some audio amp
servicing/repair book where the author states that customers often find
it desirable to know an amp's actual output power, and to return an amp
having measured its output power and noted it down for the customer's
info. The trouble is, customers are familiar with "RMS power" - but
there's no such thing! Irms X Vrms = AVERAGE power and that is all that
matters. BUT - try telling that to a typical customer!

** The term "watts RMS" has been used in relation to audio amplifier specs for many decades, since the 1960s at least.

It is a shortened expression which indicates the long accepted method of audio power measurement using a continuous sine wave into a resistive load. The figure quoted is AVERAGE watts.

Other tests exist using either the peak value of the sine wave or short bursts of sine wave, generally know as "peak power" or "music power" - the figures quotes are not average watts, but represent the maximum power available on a short term basis for music and speech.

In nearly all cases,"RMS power" and "Watts RMS" have the same meaning.

Those who say otherwise must think that "Steak Sauce" contains actual steak..


.... Phil