In the dramatic partnership between musicians and computers, we humans get the messy side. Art is all about distortion, about bending the rules to make a statement. Computers, on the other hand, strive for perfection. Nowhere is this creative tension more apparent than in quantization, the process of correcting timing by moving the notes you play to the nearest rhythmic subdivision.
Thanks to drum-machine pioneer Roger Linn, now anyone can have perfect rhythm. Today, every MIDI sequencer (recorder) sports quantization. But people quickly discovered that perfection can be boring. In this episode, we explore how to play within the rigid boundaries of quantization to get rhythms that are polished yet moving. (DMI 11-08-2007: 10 minutes 9 seconds)
To create the various drum patterns, I fired up Izotope iDrum, a $69 software drum machine that runs on Mac OS X. (See Figure 1.) I found it very easy to use, with drag-and-drop support and a clear, concise manual. For an authentic machine feel, I loaded it with some samples of the Dave Smith Instruments Evolver synth.
I made the "sloppy" pattern by triggering iDrum sounds from my Mac's keyboard, and the "tight" pattern by drawing the drum notes onto iDrum's 16th-note grid. I then exported a MIDI file of the sloppy pattern and AIFF files of the tight pattern, rendered at various Swing settings.
Loading the MIDI file into Ableton Live 6, I used it to trigger iDrum, this time running as a virtual-instrument plugin instead of standalone. I then made copies of the MIDI track in Live and quantized them to different resolutions — 16th-note, eighth-note, quarter-note, and eighth-note triplets. I added a bit of distortion, compression, and reverb to enhance the sound, and then exported the quantized MIDI patterns as AIFFs.
To demonstrate swing quantization, I imported the AIFFs I'd exported from iDrum earlier, set them to Tempo Master status in Live, and used them to "requantize" a stiff eighth-note MIDI bass riff. In other words, the drum track controlled the groove of the bass track — a slick feature. I also dredged up some additional examples from my hard drive.
Fig. 1: Here, Izotope iDrum divides a bar into 16 equal slices. The height of each red bar determines the volume of that note. The closed hi-hat track is selected.
The Glen Ballard and Scotch Ralston quotes came from the DVD soundtrack of my book, The Art of Digital Music, which I'd produced in an earlier version of Live.
I'd used a different Nile Rodgers sound bite for the DVD, so I went back to the original MP2 (!) recording to grab a more appropriate excerpt for this podcast. I used my transcriber AppleScript and the QuickTime Player to zoom in on the sound bite I wanted, and then launched Ambrosia WireTap to capture the output of the QuickTime Player. Next, I cleaned up the noise with BIAS SoundSoap and iZotope Ozone.
I'd wanted to share a Steve Reich sound bite as well, but the recording quality was so bad I never got the file cleaned up to my satisfaction. (I'd recorded that interview over the telephone into a portable cassette recorder via a cheap RadioShack phone tap; subsequent interviews used better gear and techniques.)
Once again, I recorded my voiceover directly into QuickTime Player, because Peak tends to fire up the Mac's howling fans when I try to record with it. For a mic, I tapped the SE Electronics USB2200a I've been comparing with the Rode Podcaster, another high-quality USB mic. After editing the voiceover in Peak, I imported it, the audio examples, and the background music into a new Ableton Live session, pumped up the vocals with Ozone, and rendered the mix as a new AIFF file.
Finally, I converted the AIFF mix to an MP3 in iTunes using a drag-and-drop AppleScript from Doug Adams. (I've found that iTunes is much faster at encoding MP3s than Peak, with no significant quality difference—at least at 128kbps, the rate we use for Digital Media Insider.)
The Digital Media Insider theme music came together in Live as well. The opening sound effect is a compressed mouth noise spliced onto a tone cluster I generated in Native Instruments Reaktor. The main groove is from Steinberg Xphraze. (Jim Aikin turned me on to both virtual instruments in his article "My Five Favorite Soft Synths.") The piano is from the Garritan Personal Orchestra, which I discovered when we interviewed Gary Garritan.
The theme also features a few percussion samples dredged from my hard drive. Altogether, it took just six tracks. Effects processing was courtesy of Live's default plugins and Freeverb.
Quantize This (452KB PDF)
In this excerpt from The Art of Digital Music, Glen Ballard (Michael Jackson, Alanis Morissette), Jack Blades (Damn Yankees, Aerosmith), Bob Ezrin (Jane's Addiction, Pink Floyd), Steve Reich (composer), Nile Rodgers (Chic, Madonna), and more discuss how to harness the creative tension between quantized computer perfections and swashbuckling human feel. (PDF courtesy of Electronic Musician.)
This breakthrough guitar processor offers amp modeling, unique rhythmic effects, a mic input, a drum machine, and a Pro-Tools-compatible USB audio interface for an astonishingly low price. Our impressed reviewer concludes, "It deserves a place in every guitarist's tool kit." Plus: exclusive tips and demos from inventor Roger Linn.
At the Virtual Drum Machines site, you can play dozens of wacky-sounding yet strangely inspiring drum machine emulations.
This Flash-based drum machine is the first one I've seen where the notes aren't quantized, which produces an interesting, sloppy feel. Cool sounds, too.
David Battino is the audio editor for O’Reilly’s Digital Media site, the co-author of The Art of Digital Music, and on the steering committee for the Interactive Audio Special Interest Group (IASIG). He also writes, publishes, and performs Japanese kamishibai storycards.
Return to digitalmedia.oreilly.com.