Normalizing multiple tracks at once.

[shroudoftheheretic]

I have some multiple drum tracks recorded at different times. Can I import them to Audacity and equal the volume levels on all the tracks at once?

[DVDdoug]

You can do it, but you can't really do it "at once".

The problem is... Perceived loudness depends on the the average level and the frequency content. If you "normalize", you will make all of the peaks the same, but some tracks will still sound louder than others. (There is something called ReplayGain and there is a standard called EBU R 128. These take human perception into account.* But as far as I know, there are no ReplayGain or EBU R 128 plug-ins for Audacity.)

So usually, the best approach is to do it "by ear".

The procedure is to 1st normalize all of the files to 0dB. This will "maximize" all of your files. (0dB is considered the "digital maximum", and many file formats can't go over 0dB.)

(If they all now sound equally loud, you're done!)

Now with the files normalized to 0dB you can't increase the volume of any file, so pick the quietest-sounding file as your reference.

Adjust down all of the other files by ear (if necessary) to match your reference.


Note that dynamic compression can be used to boost the average level without clipping (distorting) the peaks, but of course, it alters the dynamics of the music.


* ReplayGain and EBU R 128 suffer from the same 0dB maximum limits. And, since they are trying to match the volume of your entire music collection they tend to reduce the volume of most files.

[steve]

I have some multiple drum tracks recorded at different times. Can I import them to Audacity and equal the volume levels on all the tracks at once?

You can Normalize the "peak level" of multiple tracks at the same time, but as DVDdoug wrote, "peak level" is not always the same as "volume". It is quite likely that tracks with the same peak amplitude (the hight of the peaks on the audio tracks) may sound different "loudnesses".

as far as I know, there are no ReplayGain or EBU R 128 plug-ins for Audacity.

Actually there is an experimental "Equal Loudness Normalize" plug-in, based on the ReplayGain algorithm here: http://forum.audacityteam.org/viewtopic ... 42&t=63067
I don't think that this plug-in is yet ready for mainstream release, though my initial tests seem quite promising.

[Lawrie]

What I do now is export my project file (with all the tracks) to wave format. I then import it back into Audacity and "normalize" (in my case -1db which I think is the default) it. That creates a new mixed project file that I use for playback. I have found that all my project files (which are backing tracks) are pretty much the same volume.

I've tried importing all the wave files in normalizing them all at once, but for some reason it didn't quite work out..... for me at least . I also tried Wave Gain and didn't like it. I do use MP3 Gain for my regular mp3 files.

[steve]

I've tried importing all the wave files in normalizing them all at once, but for some reason it didn't quite work out

That should work (in Audacity 1.3.14).