Acronym for peak momentary power output.
This term refers to the maximum power output achieved for a speaker system under perfect conditions. PMPO is a controversy term, as many feel it is used as a marketing ploy, since the perfect conditions on which PMPO are based are next to impossible to achieve in a home where the speaker system is set up. The PMPO of a speaker is actually based on the maximum power output in a very small period of time (microseconds). Since no musical note lasts for such a short amount of time this peak performance cannot be reproduced in real usage of the speaker. The PMPO value is often seen listed as "watts PMPO" on product packaging. PMPO is also called peak music power output.
The alternative to PMPO is RMS (Root Mean Square), which is an accurate mathematical representation of a speaker's power output, measured over time rather than a few microseconds.
See also RMS.