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no easy way based on the information given to consumers.


even the "true RMS" values aren't accurate, so i guess it's not worth the effort... ;)

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Guest joamonte


my agaration is always to divide by abt 10-20 times.. ;D


heheehee....20 X?.....then a 200 watt PMPO will be....only 10W RMS!!!! ;D

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actually, I'm sure if there is any way to calculate or even guess it. PMPO, if I'm not wrong, is the power measured at a amp's peak irrespective of how transient it is (quite often I think only for a split second) and distortion associated with pumping out that watts. So depending on the design and how sparingly the person measuring wants to overlook things such as mentioned above, this figure can vary widely.

well this my understanding anyway. Please correct if off the mark.

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Lets see..... I did some calculations on how peak power and rms power is done. ;D. If its wrong, pls chime in.


Pwr = v2 / R = i2 / R = V x I


R = 8 ohms speaker impedance. (Impedance is frequency varying thus a complex number, but lets take 8 ohms for calculation's sake.)


V = Voltage of signal.


Voltage for PMPO is usually inflated to the max for marketing impact. So,


PMPO V = Voltage pk to pk


Voltage for RMS is very conservative, typically only about 30% of PMPO..... taking into consideration THC levels and other audio quality parameters, eg, load impedance, sustainabilty, distortion, SNR.... etc.


RMS V = 0.3 x Vpp


So for a example of 10Vpp signal,


PMPO = 12.5W

Vrms = 1.5W


The difference is a mighty 88% difference in power.


No specific formula since PMPO can be calculated with highly inflated figures and horid SNRs.


A rule of thumb for rms value is maybe only about 10% of PMPO.


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HAHA! tats interesting guyz.. from wad i learn in school.. is tat


RMS = 0.707 of ACTUAL PEAK TO PEAK (AC)current/voltage/power


eg.. 100watts(p-p)

RMS value will be 100 x 0.707 = 70.7watts (AC)


PMPO is PEAK MUSICAL POWER OUTPUT... this is a marketing strategy to promote their products.. eg.. 220watts PMPO... could be only 8WATTS RMS before CLIPPING!


PMPO has no formula... its up to the "DESIGNER" to decide on the value...




- K is a constant value wihch can mean anyting from 20 to 50.. so eg if teh "DESIGNER" is 35 years old... so K = 35


AHAHAHA! wad a joke! :o

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PMPO, if I recall correctly was first used as a Marketing Ploy by those Japanese Audio Companies selling those Mini-Compo and Ghetto Blasters to give the impression that their Mini-Compo was a real power house. As mentioned by quite a few guys this figure is not very useful as it is only the peak output for a fraction of a milisecond and to complicate matters Manufactures probably try to ramp up this value as high as possible to give an illusion of super high power.







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u want another way of calculating?


Take for example the voltage rail, say, +/-40V which will give a max signal of 40V. Then consider the min load in ohm which the output device can handle without self destruction, eg, 1 ohm.


Max Power o/p = V^2/R = 1600W

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