GEN A LISP Music Environment

 

About GEN

What is GEN?

GEN is a free, open source, MIDI Lisp Environment for music composition. It runs on the Windows OS family (xp, vista, seven, etc.). GEN is not a standalone application, it requires Allegro CL 8.2 free express edition installed on your machine    (download it from here).  Basic support for processing input midi streams is also given, but the main idea behind GEN is to provide tools for designing and testing algorithms for music generation. These algorithms can be implemented in Common Lisp. Users non familiar with Lisp can use the GEN graphic user interface to generate music according to stochastic or deterministic generation strategies. Gen results can be saved as MIDI files. Gen was inspired by the Lisp music software line represented by environments such as Common Music (by Rick Taube).

GEN was created by Guillermo Pozzati during the 90's. The histoy begins in 1992, when the author visited the Center of Computer Research in Music and Acoustics (CCRMA) of Stanford University as composer in residence. This visit was part of an exchange program between three Institutions: CCRMA, Laboratorio de Investigación y Producción Musical (LIPM) of Buenos Aires, Argentina, and the "Center for Research in Computing and the Arts" of University of California, San Diego. In that exchange project, sotfware used at CCRMA, such as Common Lisp Music (CLM), by Bill Schottstaedt, and Common Music, by Rick Taube, required knowledege of Lisp programming from the user. Consequently, in his visit, Pozzati became familiar with the Lisp programming language. Back to his country, Argentina, his interest in programming, the need to have a Lisp environment for the Windows OS (CCRMA software at first didn't run on Windows), and the curiosity for implementing some particular strategies for music generation led him to begin his own project. The first time GEN had a graphic interface was with the appearance of Allegro CL 1.0, on Windows 3.1. However, GEN remained entirely in a development stage by that time. The first complete version of the software (1.0) came in 1999, with Allegro 3.02, on the Windows 95 OS. This version was among the Finalists in the 4th International Software Competition (Bourges 1999), and as a result, a short paper about GEN was published in the Computer Music Journal, 24/3 (MIT Press). By the way, in a previous edition of the same competition, Taube's Common Music had obtained the first prize in 1996. The dependence on Allegro 3.02 (a non free product) was, at least in Argentina, a strong limitation for using GEN. Today, however, GEN was adapted to run with a free version of Allegro (Allegro Free Express Edition 8.2). GEN 1.01 is basically the adaptation of the old version 1.0. In spite of some strong limitations (there is no utility to convert Midi files to Gen files in this version, the source code is not well documented yet), there are great advantages: you can do virtually anything that can be implemented in Lisp, everything is free, open source available.
As an example of what can be done in GEN with user defined functions consider the figure below, a counterpoint under strict constraints was created and showed in musical notation. Every set of four consecutive notes and every chord in this example satisfy the [1 1 1 1 1 1] inteval vector (in terms of Pitch Class Set Theory).

 

[CLICK TO ENLARGE]

Another example is given by the concept of 'Infinite Suite', developed later by Pozzati as an exploration in the area of musical form. The algorithms for the Infinite Suite were entirely implemented in GEN as well as the music that you can hear on the Infinite Suite web page.

 

Download the Gen Manual and see section II (Installation and Test) to start. Feel free to use GEN for testing your algorithms or for creating music, but please, give the proper credits to the author.

 

The author of GEN thanks the help of argentine composer and programmer Luis María Rojas. Without his help, GEN would not exist.