Multiple audio files at exactly the same volume.

Hello everyone!

I have several audio files in MP3 or Wave format for educational purposes. They don’t have the same volume on the face of it, I plan to edit them so that they’re all at exactly the same volume (amplitude).
I’ve been using some tools and resources in Audacity and I’m not sure I’m doing the job correctly.
Could you kindly guide me exactly what tools I should use in Audacity to do the job satisfactorily.
I want to not leave them at the volume limit ie a little lower than normal but have a nice hearing in any audio equipment.
Thank you very much friends!

Apply Audacity’s loudness normalization to each of the files …
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The Audiobook Mastering Suite does a bang-up job of making everything come out the same volume. That’s its whole reason for being.

This is the short version.

It’s three tools.

If you decide you like it, there’s a Macro which bundles the whole thing into one step.

That I need to look for…

Now that you’re all excited about a solution, you should know that you can’t easily edit an MP3 file without causing some sound damage. Audacity doesn’t edit MP3. It pulls an MP3 in via a special super high quality sound format and then edits that. But then you have to make a new MP3 and that’s where the problem happens. MP3 always applies compression tools whether you want them or not.


Got it.

Audiobook-Mastering-Macro.txt (498 Bytes)
Select the song.

Tools > Apply Macro > Audiobook-Mastering-Macro

There is no “OK”.

I don’t remember how to install it. It’s different from Effects, Filters, and Analyze.

Gotta look that up. If you like it, you can use the three tools until I get it together.


There’s another one, too. Chris’s Compressor was designed so Chris could listen to opera in the car. It actively “evens out” performances so the whole orchestra comes out the same volume as that one solo soprano in the back of the stage. No constantly jockying the volume knob up and down, but it does change the performance and there is one easy bug.

I need to leave for a bit.


One important note. There’s two compressions.

Loudness Normalization looks at the whole song or performance and changes the volume once for the whole thing. That’s fine if you have commercial songs, radio shows, or other pre-digested performances.

If you have a wild-volume-swing podcast, that’s the place for Chris’s Compressor. That’s the one that cranks down through a show changing the volume as needed, as it goes. That one simulates the broadcast compressor. Note you rarely have to change the volume on the radio in your car? That’s why.



The Mastering Macro is installed from an Audacity window like this.

Tools > Macros… > Import… > Point it to that text file I posted > Open

Right. So that’s all those.

You can get Chris Compressor from here.

Tools > Nyquist Plugin Installer…

Using it is a little odd. Open the show you want to process. Add about 30 seconds of something to the end of the show. Doesn’t matter what. Chris is a look-ahead compressor and doesn’t like sailing off the end of the file. After the processing is done, you can cut the extra off.

Select the show. Effect > Compress dynamics… (down a bit). I change the first value, Compress ratio from the default 0.5 to the stiffer 0.77. That’s the only change. > OK.

We found that the 0.77 value gives an almost perfect sound of the local NPR FM radio station.

I used to record “Car Talk” off the air and burn a CD so I could listen in my car. It was just OK. It did work. Then they posted the shows on-line and the quality boost was night and day. No FM hiss and other transmitter distortions.


Also no broadcast limiters. Turns out one of the two performers mumbled in his beer and the other one had a laugh loud enough to wipe out small cities. Enter Chris’s Compressor to restore volume control. I did that for years.


One other note about Mastering. The three tools “remember” their settings, so you only have to adjust them once. Thereafter, it’s just Effect > Equalization > OK, Effect > Loudness Normalization > OK, Effect > Limiter OK.

Of course if you use the Macro, it’s always one step.


Good morning (in Brazil) everyone!

I am immensely grateful for your teaching, knowing that you are the best professionals in Audacity!
I was able to safely learn all the tools that guided me…
I am very happy with audacity.

Thank you friends!

I’ve been using Audacity for a few years now but mostly flying blind–don’t really understand what I am doing 7/8 of the time. However, I’ve managed to complete several audiobooks that passed ACX standards.

I have just installed the audiobook mastering macro, but want to be sure when to apply it. My current process is:
record raw track, save as .wav file
pass raw .wav track through Levelator
pull up Levelated .wav track on Audacity
Save as mp3

At which point in the above process is it best to edit out breaths, etc.?
At which point do I apply the audiobook mastering macro?

Thank you!

Levelator & compression* can both make breath sounds louder.
So attenuating breaths should be after those processes, (otherwise they will undo any de-breath processing).

Levelator & compression* can also increase sibilance, so any de-essing should also be afterwards.

[ * with make-up gain ]

Hi Jennie!

Thank you for participating regarding the topic I created.

01 - could you guide me what would be ACX standards?

02 - What would it be like to pass the raw .wav track through Levelator, precisely what would Levelator be?

03 - What configuration do you use in Compress?

Your request for procedures also interests me a lot. But in my case I work with music and record various instruments such as keyboard, guitar, bass, vocals, drums and others.
That’s why this teaching would be of great importance to me.

Friendly hug!