Posted by Rudi on February 12, 2002 at 15:55:43

RMS [root mean square] is a true reading, so is AES.
PEAK is 0.707 times RMS.
PEAK-TO-PEAK and MAX are both terms that mean two times PEAK.
MPO [maximum power output] is five times RMS.
PMPO [peak maximum power output] can mean anything but generely its ten times RMS.

You only see MPO and PMPO on cheap speaker manufacturers. See people without any knowledge get tricked into buying something advertised as being more powerful than it really is.

Example: 1000w PMPO loudspeaker = 100w RMS loudspeaker.
Another example: Using a 200w RMS amp driving 200w PEAK loudspeaker, might result in speaker overload, because the max safe operation of speaker is (0.7x200w) 140w RMS.