GarageBand tutorial 9: mastering and sharing

Having completed the steps in the last tutorial, we’ve now got a fully mixed song. The temptation is to go to the Share menu right away and create an MP3.

However, first it might be a good idea to master the track. This isn’t essential, but it can add an extra layer of professionalism. In very simple terms, it means applying effects and finishing touches to the track as a whole.

Mastering is one of the few things that GarageBand doesn’t make easy: in professional level DAWs you can create a mixdown on a single track and then apply effects. In GarageBand, we have to go through the following process:

1. Create an interim mixdown. When I’ve finished sorting out individual tracks, I save the project then go to Share > Export Song To Disk. I save it do my desktop as an MP3, using the highest possible quality settings so that there isn’t too much data loss. Unfortunately, GarageBand only offers AAC and MP3 encoding for export, there’s no option for lossless formats such as AIFF and WAV. However, if you save at high settings you should be fine: that means choosing ‘custom’ in the drop down box and selecting a bitrate of 320kps and setting VBR quality to ‘highest’.

IMPORTANT: Before you export to MP3, check there isn’t too much space at the end of your tracks - that is, grey space after the piano roll. If you export with it there, GarageBand may create an MP3 with a minute or two of silence at the end. GarageBand doesn’t make this easy to work out, but all you have to do is scroll along until you find the end marker - a tiny little triangle set in the top barline/time ruler. Drag this leftwards until it’s just a bar or two, or a few seconds, after the end of the piano rolls on your GarageBand tracks.

2. Once the high quality MP3 is saved, close the GarageBand project (ensuring it’s saved), and open a new, blank project.

3. This blank project will contain a single, empty track - piano. Delete it by selecting the track and hitting Apple-Backspace or by going to Track > Delete Track.

4. Once the piano track is gone, drag and drop the MP3 from your desktop into the empty grey track area. A new track appears, with the same name as the interim MP3:

Mixed song returned to GarageBand for mastering

5. You can now apply whatever you effects you like to this track - you’re effectively ‘mastering’ the whole mix - before exporting it again in final form.

Sharing Tips

When you export your final MP3, remember that although it’s a lossy format you can compress quite heavily without losing very much. MP3 is a very clever algorithm: the first data it cuts is the stuff we don’t hear - frequencies that are too high or too low, sounds that are entirely masked by other sounds, and so on.

When you export, you should find that setting the audio export quality to ‘high’ does a perfectly good job. Listen and experiment, though: if an MP3 is over-compressed, it’ll begin to sound ‘bubbly’ at certain frequencies, as the algorithm runs out of hidden data to cut and has to start chopping the stuff that’s actually audible.

The low, meaty frequencies tend to go first, but over-compression is often most noticeable in strummed acoustic guitars, which can begin to sound jangly, then bubbly, as they lose data.

Generally speaking, if you have a simple track with few instruments you should be able to get away with a minute of MP3 per megabyte - four megs for a four minute song. If you’re doing something more complicated, or using lots of effects in the same length of song (in other words, cramming more sound data into your four minutes) you may find that your files are coming out a 1.5-2 megebytes per minute of song, or more. The secret is to play around!

I hope you’ve enjoyed these tutorials - any questions you happen to have, leave a comment on the relevant post, or below, and I’ll get back to you.