rms nominal peak pmpo .......

[delhite2]

what does nominal rms mean

what does peak mean...

does it imply that 150w rms nominal = apprx 1500 watt pmpo

and 600w peak = apprx 6000 watt pmpo again peak

can 600w peak be also said as "max input power"

please throw some light..

[DrWho]

"watts rms" is an improper use of the term "rms", but is usually referring to the power handling for extended periods of time.

Peak would be the maximum power output for a very short amount of time.

PMPO is a meaningless marketing spec.

[Blvdre]

Good ole Wikipedia...

http://en.wikipedia.org/wiki/Root_mean_square

[sean5340]

Good ole Wikipedia...

http://en.wikipedia.org/wiki/Root_mean_square

Now I have a headache.

[WMcD]

There is also http://en.wikipedia.org/wiki/Audio_power

I agree with Mike entirely.

One matter not discussed is the term "nominal." If you listen to tapes of the Mercury and Gemini programs, "nominal" means everything is within the acceptable range for the rocket. In audio, it means that the figure given is pretty much not true . . . but we have to put a single number on it. So if some spec says "nominal" you can pretty much conclude there are other issues and it is very optimistic.

- - -

RMS comes into play when we are trying to measure the effect of a sine wave at the output of an amplifier upon a load, like a speaker. The sine wave goes up and down to some peak and valley voltage. One handy way of characterizing it is as follows: What is the total power compared to a d.c. (constant voltage) of some level?

The short answer is that a d.c. voltage of 0.707 the sine's peak above zero (not peak to valley) gives the same power.

- - - -

The real issue of peak power available from an amplifier goes like this: The amplifier can only put out a peak voltage which it's power supply can create and the output transistors can, at full "on" pass through without burning out. In some cases, these might give twice the power they can long term. But that is about it. This is to say, maybe 3 dB more for short peaks. This is really over-rating the amp for short peaks. Saying the amp can put out 10x more short term is just nonsense.

- - - -

The other thing you read about is peak levels in the program which is recorded in natural music. The peaks can go to 20 dB higher than average some articles say, but I think 16 or 18 dB was used in the old days. But let's look at 20 dB because the math is easy. That means 100 times the power if we have to drive a loudspeaker.

It means that you could have the amp putting out just 1 watt for most of the music (assuming very inefficient speakers). Then a big peak comes by and it is demanding 100 watts from the amp. Naturally, even the 3 dB extra (twice power) you have from the amp, short term, is not a big factor here.

Edit:

The real peaks on a recording is something which you can't really appreciate by ear. In the old days, we could look at VU meters. Even these were not precise in their read out. The mass of the pointing needle slowed down the response. You could only see it with an oscilloscope. The VU meters and the rest of the system were set up so that 0 dB on a constant tone left about 18 dB of "headroom" for peaks.

You can see peaks with modern equipment. However not all of us has that stuff.

None the less, you can see the effect using Window's Media Player set to waves and bars and play a CD on the computer. It is not calibrated in level or frequency. But, the display is an elementry spectrum analyzer with a peak hold display --- the bars push up a max level bar and holds for a while. For all its shortcomings, the price is right. It is free.

Here you can get an idea of the spectrum of your music. In a rough way, the amplifier which is fed with that music must be able to put out that peak without distortion even though the average bar is far shorter.

Best,

Wm McD