Mac-using DJs looking to get a groove on are increasingly turning to loop-based sequencing applications. Much like Sonic Foundry's renowned Acid for Windows, Ableton's Live 2.0 and BitHeadz's Phrazer 2.0 allow you to string together prerecorded audio loops to create dynamic dance tracks (and if you're a musician, they let you overdub tracks of your own). The ease with which you can assemble and play those loops is what separates an astoundingly elegant app from one that strikes the wrong note.

Making Tracks

Conceptually, Live and Phrazer are similar. Each lets you drag audio loops -- a drum or bass groove, for example -- from a bin of audio files into one of a series of tracks. By dragging several of these loops into different tracks, you build a multipart arrangement. Both programs let you adjust the loops so their tempos match, and both allow you to change the tempo of an arrangement without also changing the pitch of the tracks within it. Live and Phrazer also purportedly let you trigger individual tracks with the mouse or the Mac's keyboard, or via MIDI for live performance. Regrettably, only Live does most of these things well.

Phrazer's Faults

In our tests, Phrazer's loops didn't always sync -- for example, when we auditioned a loop. And because Phrazer doesn't currently support OS X's CoreMIDI protocol, you can't trigger a Phrazer loop via MIDI in OS X (although you can in OS 9). Phrazer supports audio in OS X only to the extent that it plays through the default output device in the Audio MIDI Setup utility, but Phrazer can't record audio from that device.

Live's Line

Thankfully, Ableton's Live more than makes up for Phrazer's deficiencies. You "play" Live from your MIDI keyboard by assigning keys on your keyboard to trigger loops and tracks. And because Live supports OS X's CoreAudio functionality, recording a live audio track directly into the program is easy.

Since we last looked at Live (mmmm; August 2002), Ableton has added a feature that lets you choose from three time-stretching schemes that make loops continue to play at the correct pitch when you increase or decrease your track's tempo. Another cool addition, Tap Tempo, allows you to change the tempo of your arrangement by rhythmically tapping a MIDI key or a Mac keyboard key, or by clicking the mouse.

While we were impressed with Live, we wish that its printed manual included an index and that its interface were more Mac-like. For example, invoking a Rename command to edit a track's name, rather than simply double-clicking on the name, is awkward.

Macworld's Buying Advice

Live, with its ease of use, implementation of OS X music technologies, and cool new features, is the finest loop-based sequencing application available. Phrazer, which lacks essential support for OS X, clearly isn't.