# Volume

Can Audacity 3.0.2 measure average volume for the whole file?

Select the file > Analyze > Contrast > Measure either Foreground or Background. That won’t give you average, that will give you RMS (Root Mean Square) which is a really close cousin. The audiobook people use RMS for loudness.

If that won’t do it, can you share why you want that?

Koz

If you are in audiobook land, we publish ACX Check which will tell you the three audiobook technical values in one shot.

https://wiki.audacityteam.org/wiki/Nyquist_Analyze_Plug-ins#ACX_Check

Koz

You mean even-out the volume, right? Making the loud parts quieter and/or the quiet parts louder? That’s “dynamic compression” or “automatic volume control” or automatic gain control".

You can use the [u]Envelope Tool[/u] to fade-up the quiet parts or fade-down the louder parts.

There is a [u]Leveller[/u] effect. (This is classified as a “distortion” effect, but when used carefully it shouldn’t sound like distortion.

The [u]Compressor[/u] and [u]Limiter[/u] effects will also even-out the volume.

I should have used the word AMPLITUDE instead of VOLUME. Can I learn the average amplitude, Windows 7, Audacity 3.0.2?

Be careful what you ask for as you just might get it. In this case, the answer is very simple. Your average amplitude is 0. This is because half of the amplitude is above zero and half of it is below zero.

Oh, well, I didn’t really mean that - what I really meant to ask for was the peak-to-peak level - no - I really want just what’s on the positive side of the zero mark. No, actually, can you rectify that for me while you are at it?

So your simple question is actually pretty hard to answer. Fortunately for us, many years ago, the great mathematicians realized that by taking the square root of a number squared, they could avoid all of this peak-to-peak and negative number junk. What they came up with was what they called RMS or Root Mean Square which is just the square root of the arithmetic mean of the squares of all of the values you are interested in. See: https://en.wikipedia.org/wiki/Root_mean_square As it turns out, RMS tells you exactly what you want to know and it can also be easily calculated.

OK, but my head is still spinning. How do I relate this to the real world? Well, since sound is simply waves, a simple tone (or sine wave) is representative of virtually all audio that you are going to see. A tone, with “volume” 1 is going to measure 2 peak-to-peak, and will have an “RMS” value of .707 = 1/sqrt(2) or about -3dB. Here is an amplitude to dB converter: https://www.silisoftware.com/tools/db.php

So, here is what to do: