Andrew
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Registered: 5th May 04
Location: Skoda Octavia Estate, Ford Puma
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How can i work this out?
My amp is 4 * 50 RMS. What is that in PMPO?
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flash22
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Registered: 13th Sep 05
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you can't
nicked from another site.....
You cant convert between the two.
RMS stands for Root Mean Square. First a varying quanity is squared, then the average is taken, then the square root. This gives an average "typical" value.
"PMPO stands for Peak Music Power Output. There is no industry standard for PMPO so you don't really have any way to find out what it means. PMPO in all likelyhood varies between manufactures, and was calculated by their marketing department. Meaning they picked a number that sounded really cool, then figured out a formula that would result in that number."
pmpo is just a theoretical max output of a amp simular to "max power" whats always taken at peak voltage of 13.8 volts in real life it just dont happen
RMS is the real value you need to look at
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Andrew
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Registered: 5th May 04
Location: Skoda Octavia Estate, Ford Puma
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Cheers dude 
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abdus
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Registered: 23rd Feb 06
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why can't it be converted?
I think it can be
there's some formula for it...iirc
it's:
RMS=PMPO/(10 times square root of 2)
PMPO= RMS multiply by 10 multiply by root 2
need to confirm though
[Edited on 23-06-2006 by abdus]
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bigrabbelfast
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Registered: 18th Mar 06
Location: BELFAST N.I
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rms is usually bout half of the "max power" so double ur rms and there u have ur rough pmpo
i think
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Scoty B
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Registered: 14th Feb 06
Location: East Kilbride, Glasgow 1873
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Why do you need to know?
Max Power modder?
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flash22
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Registered: 13th Sep 05
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it cant be calculated as there a so many variables to take into account for a start there the semiconductor threshold and the power supply circuitry construction to take into account let alone the the voltage into the amp what can swing from 11.5v to anything above 14v also you have the audio line level in to the fet/ic and the the speaker on the output side say at 4 ohm can vary +/- 5 %
pmpo is just theoretical and is worked out at the design stage
The answer to this issue lies in how they measure the output power of the device. Usually if you look at these huge numbers, you will see the letters "PMPO" underneath. PMPO stands for "Peak Music Power Output" or "Peak Momentary Power Output". Notice the word peak. The vendor of the product calculates PMPO based on the maximum power output of the device under perfect conditions and 100% efficiency. These conditions are impossible to obtain, and no device can sustain the PMPO power for any significant length of time without being ruined. The PMPO power relies on the fact that amplifiers can provide short bursts (basically on the order of milliseconds) of very high power. Over time, these short bursts when averaged with the lower output powers, gives the real value.
The Real Power
Vendors use PMPO power to hide underpowered power supplies and amplifiers. When you see something with a PMPO measurement on it, turn it around and look at the specifications. Often, the input power from the AC mains is 5 or more times LESS than that of the PMPO power. You also may see a more accurate measurement, called RMS (Root Means Square) power and DIN power. These types of measurements average output over time, creating a much more reasonable reading. Don't be fooled by cheap products which appear to put out big power.
even RMS figures can be a bit suspect due to the above variables as there taken at optimum supply voltage
[Edited on 23-06-2006 by flash22]
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