Anyway, it should be nice if the info at the speakers was uniform but the companies like to make their products more "interesting" to the consumers just to sell more................ 
I see home stereo sets with the stickers at the front 4200 watt.......... 
The problem is, a lot of manufacturers come up with such fantastic numbers to dazzle consumers. Of course, the higher the numbers, the look seems to be more attractive - 100 gazillion music peak output power! Wow!
Here's the stuff.
Peak power is normally the maximum amount of power a speaker is able to handle before it is damaged. Compared to Continuous Power which is equivalent to the RMS measurement of the speaker, Peak Power is about 4 times greater (some say 6 times greater). Thus, if the RMS rating or Continuous Power rating of a speaker is 150 watts, its Peak (sometimes referred to as instantaneous) power capability is about 600 watts.
PMPO or Peak Music Power meantime, is one which is exaggerated and does not have an exact standard on how it is measured to date. For instance, some consumer speakers are advertised as 200 watts PMPO but their RMS is only 3 watts. Or a system with PMPO of 180 watts but an RMS measure of only 16 watts. This measurement is only used primarily as a sales tool by retailers. Then, there is Peak Momentary Power Output and Peak Music Power Output. Their differences lie in their abilities to pass peaks or short train of peaks without distortion or loss of power in less than ten contiguous wave cycles. Peak Music specifies
at least ten.
. Forget about PMPO, etc. when looking into professional applications.
Continuous power is the more safe specification as it is measured by RMS (Root Mean Square, a mathematical formula). It is also the measure of the speaker's ability to receive the amp's full power continuously. An amp's higher RMS value means that it has cleaner and louder capabilities.
Now, some manufacturers measure the power at a single frequency, 1 khz. to inflate specifications. Always look for a 20-20k measurement spec. Never a single frequency measurement. Furthermore, when comparing power outputs of amps, look for the same measurements, i. e., 8 ohms, 20hz. to 20 khz, 0.1 THD. etc.
Program power or music power are never really rigorously defined. But are thought of as another variation of average power. Again, ambiguous. JBL demonstrates it this way. A 150 watt light bulb will always load 150 watts to an electrical power source, but a 150 watt amplifier will
rarely be called to deliver its full output to the speaker. This condition lies primarily on the kind of program being fed into the system and the peak and average or overall power requirements vary from program to program. Typically, the peak factor ratio normally happens at 25 dB for classical and 8 to 10 dB for rock music. As speakers can handle short peaks of power, much higher than they can sustain on a steady continuous basis, this type of specification is not as reliable.
JBL follows the IEC Standard for its speakers' testing and adopted a 3 category application. For systems that requires high peak transient capabilities like studio monitoring systems, where cleaner, high quality reproduction is a must, the ratio is X2. Thus, a 300 watt speaker is powered by a 600 watt amp. For high continuous applications, but not distorted, is necessary, like a sound reinforcement system, where it can be inadvertently overdriven or can go into feedback., IEC rating of speaker = IEC rating of amplifier. For musical instrument application, where distortion is a musical requirement, speaker is driven by an amp with an IEC rating which is 1/2 of the IEC rating of the system.
Other loudspeakers like Community, however, use Program Power Rating. The formula they use is loudspeaker power rating multiplied by 0.8 and 1.25. Thus, any power amp between (say 500 watt speaker program rating) 400 to 625 watts can effectively power the loudspeaker. Anything larger or smaller can cause damage.
What do you now use? What do you do? First, find out what the application is. Second, look into specifications. Third, make your decision on how to match the system. JBL in their book "Sound System Design Reference Manual" says, if it is a system that is stressed with full of amplifier outputs for long periods of time, like in music sound reinforcement, the amplifier's continuous output = speaker's continuous input rating. If speech reinforcement, where an operator controls the levels carefully, 2X the loudspeaker's continuous rating (3dB). For critical applications like music monitoring as in recording studios or post production studios, 4X (6 dB greater) the loudspeaker's continuous rating.
You average. I use X2 and it works well. What rating do I use? Guess ...
