10.9. Convert Software Instrument Loops

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As you may have read in Chapter 1, Software Instruments are much more trouble for the Mac to play back than Real Instruments.

Now, at first glance, that statement might seem to be illogicalin fact, reversed . After all, green Software Instrument regions contain very little dataonly a list of note triggers ("Play middle C for one beat, then C sharp for two"). MIDI files take up only a few kilobytes on the hard drive. They're absolutely minuscule compared with digital recordings like Real Instrument regions, which take up 10 MB per minute. So why isn't it easier for the Mac to play the little files than the big ones?

Because it must also generate the instrument sounds , not to mention processing them with effects, as it plays each MIDI note. It's not the triggering that's so much work; it's the synthesizing.

To play a blue or purple Real Instrument region, on the other hand, the Mac just plays back a bunch of sound data that's already fully formed on the hard drive.

In any case, exploiting this little quirk of Software and Real Instruments is an excellent way to reduce the load on your Mac's processor, because GarageBand makes it easy to convert the former into the latter.

For example, GarageBand offers at least three ways to convert green loops into blue ones that are easier for the Mac to play:

If you press the Option key before dragging a green loop out of the Loop browser and into an empty spot on the timeline (and keep the key down), GarageBand creates a blue Real Instrument track. It then converts your loop into the familiar blue sound waves found in a Real Instrument region.
If you enjoy that auto-conversion so much that you'd always like GarageBand to convert green loops, choose GarageBand Preferences, click the Advanced tab, and turn on "Convert to Real Instruments." From now on, every loop you drag out of the Loop browser (into a blank spot in the timeline area) creates a blue Real Instrument track and region.

not convert it to a blue one.
You can drag a green loop that's already in a track into a blue Real Instrument track. GarageBand converts it to a Real Instrument region as described on Section 2.3.2.

Remember, though, that once converted to digital-audio form, a loop loses much of the editing flexibility it once had. You can no longer change individual notes inside it, for example.

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