This tutorial describes how to do a quick audio edit in Soundtrack Pro 2, part of Final Cut Studio 2 (Apple). You'd want to be familar with this e.g. for processing lecture recordings. When you are done with this, you can read Encoding mp3 with iTunes. Some more background is here: Dynamic Range Compression.

[edit] 1 Opening and saving a wav file

Open Soundtrack Pro. The standard layout should look like this:

If not, then press F1 or choose Window > Layouts > Standard

Find a wav file you'd like to process. Ctrl-click and choose: Open in soundtrack

The file open in soundtrack looks like this:

Immediately do a 'save as', saving the file to a new name. Choose File type = Audio file project

[edit] 2 Processing the file

If your file is stereo, and you've only used one channel, the you should convert to mono. (Some solid state recorders can record mono files, which particularly for longer files is preferable, as it saves you the effort of converting to mono.)

So if you just need one channel, then the first step is to convert the file to mono. Select Process > Convert to Mono

In our example, we want the left channel:

Confirm by pressing ok.

[edit] 3 Trimming

We now want to trim the start and end off the file. The recorder should have been running a while before the lecture started, so you need to trim some audio from the beginning.

Also, the recoder would not have been switched off immediately after the event was over, so you need to trim something from the beginning.

The result look like this.

You may want to insert a 'Fade in' at the start, and a 'Fade out' at the end.

[edit] 4 Normalisation

The next step is to normalise the audio. Choose Process > Normalise (Apple-L)

Your file now looks like this:

[edit] 5 Dynamic Range Compression

To improve the audio level, you now need to apply dynamic range compression, background notes available here Dynamic Range Compression.

Play through various parts of your audio, observing the level meter. They typical level will be around -6 to -18dB. Remember this value.

Then choose Process > Dynamics > Compressor.

The compressor looks like this:

You choose the threshold to be the typical volume level you observed before. Make sure that auto gain is set to 0dB. Set the rate to 4:1. You can listen to to the effect by clicking the play button. When done, click apply.

Compressor now works through your file, and you should see a 'thickening' of the waveform.

After the compression, the audio level should be higher than before, ideally above -6dB most of the time.

[edit] 6 Export

You are now done! Export your file:

This time choose 'aiff file' or 'wave file'.