Hi ,someone know how convert watts PMPO to RMS?

 

You can't really convert the Peak Music Power Output (ahem) rating to RMS. PMPO is not much more than a marketing ploy, there is no real information contained in the number given, or how it was obtained.

Think of it this way... those tiny little plastic computer speakers powered by batteries or a tiny wall adapter, with a rating of 300 PMPO. You would be lucky to get 300 Watts of heat from them if they were plugged into the wall directly, LOL.

Audio is one of those worlds where unfortunately all sorts of hokey information is made up simply to look impressive on the packaging.

 

Quite right, PMPO bears no resemblance to a proper specification - I've seen PMPO values range from 10 times RMS to over 100 times RMS. Basically if anything is rated in PMPO it's just a load of rubbish, no honest manufacturer would quote using that!.

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As an example of how useless PMPO is, a buddy of mine has a set of computer speakers rated at 960 watts PMPO. His entire system takes up less space then the woofer in my speakers rated for 400 watts RMS. While not a high end amplifier by any stretch of the imagination, the amp I use is rated for 440 watts RMS into a 4 ohm load (2 channel) and it weighs a good 55 to 60 lbs. Most of that number comes from the massive transformers in it.

If it is rated in PMPO, there is a good chance that it is junk.

 

Mine is 400W + 400W RMS into 4 ohms, or 800W bridged into 8 ohms, and includes an eight channel mixer with two digital effects channels - it only weighs 12kg - because it's class D and uses a SMPS.

BTW, I don't 'just happen to know' it's weight, I've just carried it downstairs ready to take to the gig Saturday (along with all the other gear), and I happened to notice the weight on the box.

Not just a chance, only junk uses PMPO ratings.

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Thanks all ,therefore PMPO= JUNK,and is a invention of each manufacturer.

 

Paul Obrien

divide PMPO by the number of speaker channels then divide the result by 2 and you might come close to the RMS output or you may not.

 

That would only convert PEAK to RMS, PMPO would need dividing by a higher, unknown, number - different for every value!.

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PIC programmer software, and PIC Tutorials at:
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Music Power ratings are high because the measurement is for only a moment, before the power supply voltage drops due to being loaded. The frequency and amount of distortion aren't specified so could be anything.
Peak power is simply double the real power.
So Peak Music Power is meaningless.

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Uncle $crooge

 

well my 240 watts pmpo turned out to be 3 watts each so 6 watts total but that was only the speackers I bet thear was no more than 1-2 watts per channel there judging but the ic and pathetic heatsink. then the transformer 9V 300 mA so you go figure. I think this pmpo thing only lasted a few years as now they are all back to rms but don't take their word for that either my 10 W woofer on my 2.1 system is really 8 wats and I darn't wonder what the speakers really are, but it is true that really 10 watts would be way too loud so many people just don't realize that 1 watts is sometimes ample unless you in a car and so ok I'll give you up to 5 watts per channel. All i see in higher power than necesary is better quality at a normal power level

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I AM the exeption that disproves the rule in many ways but the rules still apply (unfortunately)

my site:www.simons-photography.com
http://rushdenrotaract.org.uk

 

Yeah, PMPO seems to have dissapeared a bit, and manufacturers do quote RMS now quite frequently. However, that can vary quite greatly as some RMS measurements are taken at 1khz sine wave only and don't quote distortion.

My new Hi-Fi amplifier is rated at 2x40W, the same as my old one, but it is significantly louder as it is measured across the full frequency spectrum and distortion at all levels is under 0.03%. 2x40W RMS from an amp like that is very loud (though loudness depends on the speakers, mine are quite sensitive), I wouldn't dare put it over half, doors start rattling and things well before that.

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Angry!? I'm absolutely electrolytic!

Will have to make do with myspace now I guess...

 

yep well people got wise to publicity crap and it only worked when A was still using rms and B started quoting pmpo but then A started using pmpo as well so we were back to square one then booth A and B started telling it again in rms probably telling us what a joke pmpo is having used it though themselves its called pubblicity

__________________
I AM the exeption that disproves the rule in many ways but the rules still apply (unfortunately)

my site:www.simons-photography.com
http://rushdenrotaract.org.uk

 

We still suffer the equivalent of PMPO mentality in power tools. Its surprising to see a small woodworking router or vacuum cleaner rated at 5 HP!

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RadioRon

 

They must measure the HP of those motors that have brushes when they are stalled and are beginning to smoke.

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Uncle $crooge

 

PMPO = JUNK

is a correct statement, its' used by advertising agencies to promote so called hi powered audio equipment which is in fact substandard and only provides a fraction of the audio output value quoted.

RMS is the correct value to be used and quoted over which frequency range.

Used to be RMS at a steady 1 kHz frequency from my memory.

As already said applies to powertools too, 1kW drill yeh??
Looking at the motorsize, perhaps 400 Watt, they probably quote the power rating with motor armature in locked position, It may draw 1 kW, it will only last also a very short time prior to go up in smoke and sparks.

Cheers Raymond