Root mean square. The square root of the sum of the squares of a set of quantities divided by the total number of quantities. Used when monitoring ac (alternating current) signals. Many power supplies, for example, issue an ac signal. This needs to be converted to a dc (direct current) signal for the PC interface. The solution is a signal conditioning input that produces a dc signal proportional to the rms of the amplitude of the input signal. The rms operation means the reading will always be positive. according to google's dictionary. By my understanding it's a measure of n values squared, added, divided by n, then root-ed. It's some kind of measure of performance peaks over a long period of time. It can be used in physics, statistics and electronics such as audio and loudspeakers. http://en.wikipedia.org/wiki/Root_mean_square In the area of audio it's not 'really' called RMS Watts, but 'average sine wave power' according to http://www.hifi-writer.com/he/misc/rmspower.htm. Also there is something called 'mean heating power' when referring to DC, when 'mean power in watts' is used when talking about AC. DC is produced by the computer if I'm not totally mistaken, so does this mean that you have to calculate how the output power in watts (or amps??) from the sound card is used up by the speakers? Is the AC from the wall socket transformed to DC via the computer's power supply? Is the CPU creating its own Hz - its own ups and down of volt? Just to get it all right... Watts = Volts * I (Current) and when the electrical current follows a sine wave (AC) it's the voltage that goes up and down (plus to minus and back)? So... given the voltage output and amps output at every given instant received from the sound-card in the computer, we can calculate W? Taking all those aggregated/summed (enigma sign...) watts, squaring them, (and adding via the enigma), then multiplying all that by n^-1, given that n is the total amounts of measurements, gives us RMS watts? Or is it, as the hi-fi writer state, the average sine wave power we get then? However, since power is measured in watts ----? What's the difference? Thanks for reading all my thoughts and even more thanks for any responses!