The Max Factor

Jun 1, 2002 12:00 PM, By Gary S. Hall

             

In the early 1980s, I had the pleasure of conceiving and designing a true classic, the Lexicon PCM42 digital delay. At that time, I was interested in using looping delays that could be beat-synchronized with drum machines and arpeggiators, and I incorporated some of my ideas into the '42. With the resources of Lexicon, I was also able to build a great-sounding delay for general use. The original '42 became nearly a studio standard; a used PCM42 fetches a higher price today than it did when it was new.

I've always taken pride in having created the PCM42. I felt, and still feel, that there's a special richness and immediacy in creating music with long delay loops with feedback, and I'm pleased to claim my little bit of history in this area.

Recently, I've been thinking about what I would do if I were to redesign the PCM42. Among the things the PCM42 would need most is the ability to dial in delay times as beats per minute and note values. There would be other changes, as well:

• My updated PCM42 would be entirely software, built with a “construction kit” such as Cycling '74's Max/MSP.

• It would be a live-performance environment, with analog inputs and outputs.

• Delay loops would be beat-synchronized, with options for master or slave operation.

• It would be semimodular, with multiple units that could be connected in series or in parallel in any combination.

• The device would offer multispeaker surround outputs as an option.

I found that I can do all of this within the Max/MSP environment, and I'm pleased with the musical results I'm getting. In this article, I'll give you a full working multichannel real-time looping device with sophisticated features, and I'll show you exactly how to build it. You can build the system from scratch or just download the completed program from the EM Web site for instant fun.

THE MAX/MSP ENVIRONMENT

Max/MSP, published by Cycling '74, is a visual programming language for both music and audio. Originally developed by Miller Puckette, Max has been available since 1991. Max offers something that I've never found elsewhere: a complete software “construction set” of basic I/O, control, and processing routines that can be connected to create any function imaginable. It is truly the visual programming language of MIDI.

A couple of years ago, Max took a huge step forward with the introduction of MSP (Max Signal Processing). An integral part of the Max 4.0 package, MSP extends the concept of Max into native audio processing, a tremendously exciting development that makes it possible to create arbitrarily complex effects processors and signal generators at will.

One of the nice things that Max has always offered is its free run-time engine. With it, any Max program (called a Patcher) can be loaded and run by anyone. Controls in the user interface are fully active, but no changes can be made to the Patcher itself. Thanks to this policy, Max/MSP developers can distribute their work freely.

HARDWARE AND SOFTWARE

Max/MSP runs exclusively on the Macintosh, although a PC version is under development. OS 8.6 or higher is required (I run OS 9.1), but OS X is not yet supported.

The device we'll build is a real-time audio processor designed to work with live audio inputs, so a stereo or (preferably) multichannel audio interface is needed. Max/MSP supports ASIO and Apple Sound Manager drivers. I've used the program successfully with an Emagic EMI 2/6 and a Mark of the Unicorn 828.

Because it is based on long delay loops, the Patcher we're going to create is memory hungry. It doesn't require much for essential operation, but the more delays you use and the longer they are, the more memory you will need. As a benchmark, if you run at a 44.1 kHz sampling rate, eight seconds of delay memory (equivalent to four bars at 120 bpm) consumes about 5.6 MB.

To run the Patcher, you need some form of Max/MSP. Readers who already own Max/MSP can jump right in, of course, but if you don't yet have the program, you can download the free Max run-time engine or the complete Max package from Cycling '74's Web site (www.cycling74.com).

Running the virtual delay unit is fun and (I hope) musical, but what I really want to do in this article is show you how to modify and customize the program to meet your own needs, as well as to create your own processing and synthesis programs from scratch. This is the excitement of Max/MSP, and you should definitely give it a try.

Luckily, Cycling '74 allows you to download the complete program for a free 30-day trial. That's easily enough time for you to work through this example and some of the excellent tutorial material that is included with the download. Within your 30 days, you can do anything you want; after that the program will refuse to operate until you get an authorization code from the manufacturer. It's a good and fair system. I offer one caution, though. If you're running the trial version, do not try to change your system date and time. That will cause the program to immediately time out.

The Max/MSP Patchers shown in this article are available for download as a single archive from the EM Web site. To help in coordination, Patchers are identified according to the figure in which they appear. To get the most from this article, get Max/MSP (demo or full version) and build these Patchers yourself in addition to studying the downloadable versions. If you like, however, you can also download the Max/MSP run-time environment and use any or all of these Patchers as they are.