RMS is the standard method of measuring AC, as it gives a voltage value equivilent to DC voltage (for ohms law and other calculations)
In AC the voltage is constantly fluctuating (duh
) and the peaks of the waves are sqrt 2 (1.414) times the RMS value...
So to convert between peek and RMS, either multiply by root 2 (1.414) (RMS-peak) or 1 over root two (0.707) (peak to RMS)
RMS is the standard, no voltage/wattage specs should not be given in any other method. Only those cheep computer speakers inflate their specs by giving a peak-to-peak power, since its always 1.4 times higher for ANY speaker
For audio, average and peak generally mean somthing different... The average level of the sound is very soft, but sudden peaks (drums, transients, etc) will suddenly increase the power by 10 dB (a lot!). Rememver, your hearing is logarithmic, so you need many times the power for a small increase in volume...So a speaker must be able to withstand huge peaks even though most of the signal is much softer. That is what they meen by average/continuous RMS and peak RMS. (note should be given in RMS units) The average is the most power the voice coils can put up with for long periods of time without burning up, while the peak value is given for short bursts at a time without damage (the peaks can be much higher because the voice coils can cool down after the short burst, but if it was played continuously at that level, it would eventually burn up)
Many people judge speakers only by power ratings, which are completely meaningless. Any speaker will reach its Xmax (maximum excursion, IE cones bottom out and create huge amounts of distortion and no further increase in volume) way before its maximum power rating....
Then there's sensitivity, My 95dB sensitivity (ok maybe a bit overratted) Axiom M22's
will play at the exact same volume level as those cambridge speakers with 1/8th the power...
And finally, after everything i've said, none of it matters in terms of sound quality. Listening is really the only way of telling... That said, the $300 price range is extremely competitive with many "giant killer"s in that range. Speakers from Axiom, PSB, Paradigm, NHT, NoRH, Acoustic Energy, Diva, etc have recieved many postive reviews