Hey guys, I have seen a lot of questions, and answers regarding RMS wattage, and nobody has described what it actually means, so I thought I'd give a little insight.

RMS is an acronym for "Root Mean Square",

That might not be the clearest way of putting it though. If we take into acount that the Mean of 2 numbers is simply the average of the two, the abreviation makes a little more sense. We are taking the Root of the average of the Squares of the Voltage.

RMS is the only true way to measure AC voltage acurately.

Hope that clears up a few qusetions regarding this odd acronym.

regards, Mark

 

TO expand on mark's point, Root Mean Square is how you arrive at the number.

The problem is that the average of any sine wave is exactly Zero, because it will have equal parts above zero, and below. so what mathematicians did is decided to square the value at every point on the sine wave, because the square of a negative is always positive, and the square of a positive is always positive.

So after they SQUAREed the values, they took the average or MEAN value, and then found the square ROOT of that value, which is how we arrive at the RMS value of a sine wave.

 

You forgot to mention that RMS only works for sine waves.
Audio never comes in sine waves, just AC

 

a sine wave can be compaired to ac. a wall outlet is what 110v at 60 hz. thats what about 320W at 60 cycles...

 

apparently you've never been to an SPL show where they play sine waves...

 

how long ago did you take math 30?
thats the unit that was just coverd.
sine waves can be compared to the in and out movement of a speaker.
i agree that music is ac.

 

errr..... well there really is no such thing as RMS 'wattage' (power)... I think thats been covered before though, so I wont go there...



Any waveform or sound you can come up with is a collection of sine waves...... and provided your meter has wide enough bandwidth you can most certainly find an RMS voltage or current for any AC signal.....