After working on a basic concept and developing an initial max/msp application, I started composing the various mini compositions that would be ordered into the longer computer generated aleatoric form for Descarga. The original idea called for loops containing one cycle of a particular cell (6 sec. max) triggered and retriggered by the computer, but I quickly decided that this would lack the detail necessary, and decided to create longer sections with 8-20 repetitions of a cell that developed in an interesting way.
Towards this goal I created a custom combi patch in Reason using the redrum drum machine. This combi (pictured below center and right) used various effects to allow for manipulation of sampled percussion sound, such as pitch shifting, tempo relative LFO effects, distortion, etc. I loaded each redrum with percussion sounds from various sound libraries and duplicated each combi so that raw sampled sound could be mixed with manipulated sound. Ten or more redrum combis were stacked and mixed to produce the final mini compositions (below left).
After completing the 56 mini compositions in Reason the final step was to refine the max/msp program to trigger the audio correctly. The central programming concept is that any one of the seven rhythmic cells can transition into any other one. The final max/msp program (below left) uses a large preload message to put all 56 audio files into RAM. The main organizing element is a detailed coll object (below center) wherein each line has 19 items; 6 listing possible next mini compositions, 6 listing the number of repetitions of a given cell contained in that mini composition, 6 listing possible next transitional sections, and 1 giving the length of a piece’s rhythmic cell in milliseconds.
The coll object is sent randomly generated numbers within a certain range, and sends out code that is parsed and randomized by the program to insure the transitions make musical sense.
The end of an audio file’s playback in sfplay~ triggers a new number to be sent to the coll object. The performance interface (below right) uses data about the duration of a rhythmic cell in milliseconds and the number of repetitions to create a display that tells the performer how many repetitions remain until a new rhythm begins, and what that new rhythm will be. For instance, the example below shows that the seven beat “2gin” cell will repeat 10 times before the transition to another seven beat cell, “part,” begins.
The piece is timed and, after a set time, the main coll object is closed and another one is used that guides the piece from whatever rhythm is playing to the intro/outro rhythm called 18. The piece begins with a 16.5 second bass intro (computer tacit), equivalent to 4 cycles of the 18 rhythm that begins the piece. In between there are more than 1,000 possible outcomes.
