Apple Loops are Apple's answer to Acidized WAV files. As you might expect, only Apple products can take advantage of Apple Loops' special features, such as meta-tags, transient markers, and embedded MIDI data. Even so, with a small investment in Apple's GarageBand 2 ($79 as part of the iLife suite), you can put those features to good use in other audio software. I'll cover several ways to do that using GarageBand or any of Apple's other audio applications.
When Apple Loops were first introduced with Soundtrack in 2003, the supply was limited, and you weren't likely to encounter them outside of Soundtrack. But things have changed considerably; Apple released GarageBand and the highly regarded Jam Pack series of Apple Loops. Independent loop-library developers such as Big Fish Audio (www.bigfishaudio.com), PowerFX (www.powerfx.com), and Zero-G (www.zero-g.co.uk) now include Apple Loops in many of their libraries. In short, you may have Apple Loops lying around that you don't even know about.
Apple Loops can be loaded as standard AIFF files into non-Apple products, and you can, of course, use them as you would any other audio files. For example, you can use Ableton Live's time warping and pitch shifting capabilities to adapt the loops to a Live project, and you can use Propellerhead ReCycle to convert them to sliced REX2 files for use in Reason and other applications that support that format. But you can also utilize the built-in features of an Apple Loop by loading it into a compatible Apple application, and then either syncing that program to your preferred audio application or resaving the modified loop for loading into that application.
The Real Deal
There are two kinds of Apple Loops: Real Instrument and Software Instrument. Real Instrument Loops are akin to Acid files; they contain meta-tags with information about the file such as key, tempo, time signature, number of beats, musical genre, and so on. Additionally, they usually contain transient markers for time stretching a loop to fit a song's tempo. Software Instrument Loops contain all the information in Real Instrument Loops (including the audio content) along with MIDI data and information about the software instruments and effects used to create them. That information can be used to re-create and edit the loops in Logic and GarageBand.
FIG. 1: Soundtrack Pro''s Apple Loops browser is the fastest and most flexible tool for finding Apple Loops that fit a specified criteria.
Software Instrument Loops have an obvious advantage: you can time-stretch and pitch-shift them as MIDI processes, and the result will exhibit none of the artifacts associated with those processes when they're applied to audio. A majority of the Apple Loops produced by Apple and all of those produced by third-party developers, however, are Real Instrument Loops. You can create your own Apple Loops of either variety in either Logic or GarageBand.
Needle and Haystack
One of the advantages of Apple Loops is that you can search a group of them for files that match specific criteria. Generally manufacturers categorize sounds in audio libraries by grouping similar files into folders and using arcane naming schemes. Apple Loops' meta-tags encode a wider range of information and allow files to be matched to multiple criteria.
GarageBand, Logic, and Soundtrack Pro all have built-in Apple Loops browsers, but Soundtrack Pro's is by far the fastest and most full-featured (see Fig. 1). If you're interested primarily in Real Instrument Loops and could use a first-rate audio editor that includes an 8 GB Apple Loops library, Soundtrack Pro might be a worthwhile investment. (A full review of Soundtrack Pro 1.0 is available online at emusician.com.)
The browsers in Logic and GarageBand are a bit slower, and if you have a large library of Apple Loops, you'll spend a lot of your browsing time staring at spinning rainbows. Also, those browsers are not as flexible and don't display as much detail as Soundtrack Pro's, but they both do the job.
Hearing Is Believing
When working on a song in a non-Apple application, you can browse for Apple Loops in several ways. The simplest and least flexible way is to mix down the relevant section of the target song to an audio file and import that into the browser host. A better alternative is to use ReWire or MIDI synchronization to link the browser host with the other application. Logic and GarageBand will function as ReWire masters, Logic will send MIDI Clock and MIDI Time Code to other applications, and Soundtrack Pro will send and receive MIDI Clock and send MIDI Time Code. That gives you a variety of connectivity options, depending on the software that you're using.
I most often use MIDI Clock to slave Live or Reason to Soundtrack Pro for browsing Real Instrument Loops. I then cycle the section of the song I'm working on, select the Search tab in Soundtrack Pro's browser, set up the search criteria, and step through the displayed Apple Loops. The selected Apple Loop automatically plays in sync with the song. If I like what I hear, I right-click on the Apple Loop to add it to the Soundtrack Pro project bin. In GarageBand or Logic, you need to drag the chosen Apple Loops directly to an audio track. Whichever browser host you use, you'll need to set its key to the song key in order to have the Apple Loops transposed correctly.
Another alternative is to export the transposed and time-stretched Apple Loops from the browser host as standard audio files. Soundtrack Pro and Logic have export options for exactly that. In GarageBand, use the Export to iTunes option, which exports either the entire GarageBand song or the section within the cycle markers (if cycling is turned on). GarageBand and Logic also allow you to export the modified files as new Apple Loops.
Yet another approach is to record the audio output of Soundtrack Pro or Logic directly in the other audio application. Neither Soundtrack Pro nor Logic function as ReWire slave applications, but the free Sunflower utility from Cycling '74 (www.cycling74.com) provides an alternative audio pathway.
The Soft Side
You have several more options with Software Instrument Loops, but for those you need to use either GarageBand or Logic. In their browsers, Software Instrument Loops are distinguished by their icon, which is a green note instead of the blue waveform icon used for Real Instrument Loops (see Fig. 2).
FIG. 2: In the Logic and GarageBand browsers, Software Instrument Loops are distinguished from Real Instrument Loops by their green note icons.
The setup for synchronization is the same as previously described for Real Instrument Loops. The only difference in procedure is that Software Instrument Loops must be dragged from the browser to a MIDI track in Logic or GarageBand; otherwise, they will be inserted as Real Instrument Loops. The target MIDI track must be empty; otherwise the software instrument and effects already assigned to that track will be used instead of the intended ones.
With Software Instrument Loops, you get artifact-free time stretching and pitch shifting and you can alter the MIDI data and the software instrument and effects plug-in settings. The ability to alter the MIDI data expands the usability of Software Instrument Loops considerably. For example, you can modify individual note pitches, timing, accents, and durations as well as change software instruments and effects (see Web Clip 1). And, because the Software Instrument Loops included with Logic and GarageBand (they are the same collection) only make use of software instruments and effects available in GarageBand, the ability to rework them to use other Logic and Audio Units plug-ins adds another dimension.
New Loops from Old
Once you've modified a Software Instrument Loop, you can export it from either Logic or GarageBand as a new Software Instrument Loop or as a standard audio file. You can also export its MIDI content from Logic as a separate MIDI file, which allows you to use it in other applications with software instruments and effects that may not be available in Logic.
FIG. 3: The free Apple Loops utility allows you to alter an Apple Loop''s meta-tags and transient markers.
If you export it as an Apple Loop, you can then use the Apple Loops Utility to update its meta-tags and transient markers. Soundtrack Pro ships with the Apple Loops Utility, but you can also download it directly as part of the Apple Developer's Apple Loops SDK (developer.apple.com/sdk/#AppleLoops). The utility's control panel has two pages: one for creating meta-tags and one for placing transient markers (see Fig. 3). Exported Apple Loops will automatically have their key and tempo information updated, but you may want to modify their meta-tags to reflect changes in instrument or style. If you've modified the MIDI content of a Software Instrument Loop, you will also need to update the transient markers to reflect that.
Working in other software applications doesn't have to mean abandoning your Apple Loops library. Integration can be as simple as using GarageBand's browser to identify appropriate loops or as complex as interconnecting several applications for synchronization and audio exchange. Either way, there's no reason to be left out of the Apple Loop.
Len Sasso is an associate editor of EM. He can be contacted through his Web site at