Normalizing Audio Levels in Soundtrack Pro

[ This article was first published in the January, 2006, issue of
Larry’s Final Cut Pro Newsletter. Click here to subscribe. ]

Last month, Idiscussed how to replacebad audio with clean ambient noise. This month, I’d like to show you how to use the Normalize feature in Soundtrack Pro to raise audio levels in a clip, without running the risk of sending them into distortion.

First, though, let me explain normalization. When we raise the level of an audio clip, there’s always the risk that we will raise it too far, causing it to distort. In Final Cut, there is no effective way to prevent this, short of listening to every clip and adjusting the volume.

Normalizing takes a different approach. When you normalize a clip, you are raising the volume of the entire clip so that the loudest portion of the clip equals the normalization value. In other words, normalizing raises the volume of a clip, without running the risk of distortion.

When dealing with a very soft clip, normalization can be a huge help!

Here’s how to normalize a clip in Soundtrack Pro:

1. Open Soundtrack Pro and open the clip you want to adjust. Or, you can Send the clip from Final Cut to a Soundtrack Pro Audio File project. Or, drag the clip on top of the Soundtrack icon in the dock or Application folder. Or, … well, shoot, just open the clip.

 

 

2. Here’s a clip opened in an Audio File project. An audio file project allows us to edit a single clip. Clips can be either mono or stereo, however, we can only edit one clip at a time.

 

 

3. When I play the clip, the Meters tab shows me that the loudest portion of the clip is -8.3 db, while the majority of the clip is down near -12 db. In other words, this is too quiet.

 

 

4. Double-click the waveform to select the entire clip.

 

 

5. Choose Process > Normalize to open the normalization dialog.

 

 

6. The Normalization dialog defaults to a 0.000 deb level — which is TOO HIGH! It also shows that the maximum volume of the clip is a little more than -8 db. What this dialog says is that it will raise the volume of the selected audio clip such that the loudest portion of the clip equals 0 DB.

 

 

7. If I am normalizing a clip that will be played by itself and not part of a mix, I will normalize it to -3 db, as shown here. If I am normalizing a clip that will be played as part of a mix, I normalize it to -6 db. I can set this level either by moving the slider, or by typing in a value. In this example, I typed in a value.

 

 

8. Here’s a comparison of the clip before and after normalization. Notice that the top waveforms are small, while the bottom waveforms are much taller. The clip is now significantly louder, as indicated by the taller waveforms.

 

 

9. Now, when I play the clip, see how the loudest portion has increased from -8 db to -3 db, as indicated by the red circle. Also, the overall volume of the entire clip is increased, without any risk of distortion.

 

 

10. Sometimes, though, a part of the clip is too loud — a cough is a good example. In that case, if you normalize the entire clip, the loud cough prevents the rest of the clip from increasing in level. In these cases, you want to select the audio you want to increase, as indicated here, then normalize as we’ve just discussed. In other words, select the audio to exclude the cough, then normalize.

 

 

11. One of the real benefits of Soundtrack Pro is it’s ability to non-destructively edit audio. For instance, if you UNcheck the Normalize check box in the Actions menu, you can compare what your clip sounds like with, and without normalization. This is a great way to make sure everything sounds the way you want it to.

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