Difference between RMS and PMPO in radio speakers
The RMS power value is the real music power output of a speaker. It is a true indication of the output power across the full range of frequencies produced by a given speaker.
PMPO (Peak Music Power) refers to the maximum amount of power output that the speaker could produce if driven to it's peak. A PMPO rating is not indicative of the output of a speaker across a wide frequency range and therefore not particularly useful as an indication of speaker performance.
You cannot compute RMS output from PMPO and vice-versa as they do not measure the same characteristics.