Average noise level of a sample

Audacity Help Forum Windows
1

Hi,

I am using Windows 7, and Audacity 2.0.5. I obtained the .exe installer.

I would like to know if there is an easy way to obtain the average noise level in dB of a selected section of an audio track.
Basically I want to run several noise tests of machines running in a different room, before and after adding sound proofing in the room.

I guess I can look at the spectrum, but I was hoping to get a single average number over the whole bandwidth.

Thanks,
Benoit

2

Download stats.ny from [u]this post[/u] and copy it to your Plug-Ins folder. Then open Audacity, load your file and go to Analyze → Wave Stats. You can use RMS or A-Weighted RMS levels. You may also want to check the peak levels, since noise generally has a lot of randomness.

You can’t get actual dB SPL readings unless you calibrate your setup with an SPL meter, but the relative readings will be valid as long as you don’t change anything in your recording setup. i.e. A 6dB drop in your digital (dBFS) reading means a 6dB drop in your acoustic (dBSPL) level.

3

Thanks DVDDoug!

This is pretty much what I was looking for. I will do some experimentation with it. I’m not sure if the stats only will be enough to make the comparisons, since the spectrums are obviously more informative. I may have quite a lot of background noise at different frequency, so if that’s the case, comparing the spectrums will help separate the background from the noise source of interest.

Regards,
Benoit

4

“A-weighted RMS” is most commonly used for comparing audio signal noise levels.