# Help with RMS/High-Current/Discrete Output of Subs...

Discussion in 'Archived Threads 2001-2004' started by altan, Nov 29, 2002.

1. ### altan Stunt Coordinator

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Can somebody explain what

"Amplifier: High-Current, Discrete Output"

with values

"750w/250w RMS"

means? (This was taken from the Paradigm PW-2200 specs)

SVS, from their 20-39PCi simply says

"320 watt RMS BASH amplifier"

I suppose it is only fair to compare the Paradigm's 250w RMS with SVS's 320 watt RMS, correct?

What exactly is RMS?

... Altan

2. ### Edward J M Cinematographer

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Stolen from somewhere on the web:

Root-mean-square (rms) refers to the most common mathematical method of defining the effective voltage or current of an AC wave.

To determine rms value, three mathematical operations are carried out on the function representing the AC waveform:

(1) The square of the waveform function (usually a sine wave) is determined.

(2) The function resulting from step (1) is averaged over time.

(3) The square root of the function resulting from step (2) is found.

What does it mean to the average Joe HT enthusiast?

It's a standard way to compare (apples to apples) the relative power output of different amplifiers into a given average impedance load over a given frequency range at a given distortion level.

While the "dynamic power" rating is of some importance, some manufacturers tend to abuse the term, and try to make it appear as if they have a 700W amp when in reality it is only capable of 300W RMS continuous output. The most honest manufacturers will list the RMS rating.

Here's a made-up example of what I would look for as giving a pretty complete picture of what an amp is really capable of:

500 watts RMS continuous output into a 4 ohm nominal impedance from 20-20K Hz with no more than 0.5% THD.

Hope this helps.

Ed

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