Channel Music is a piece for wind ensemble and is comprised of 13 sections. Each section has a duration of one minute, making the piece a total of 13 minutes in length. The wind ensemble is broken into 13 divisions of three to four instruments. There are 13 source motives within the piece, each written for a group of three instruments.
A new motive appears in each section, along with all the previous motives. The new motive holds the primary importance in its section. Also, one of the 13 instrumental groupings is designated as the primary grouping for the new motive. Other instruments play the motive, but the instruments of the primary group are those through which the new motive is heard for the first and last time. In the final (thirteenth) section, each instrumental group plays a different motive. The motives do not appear perpetually within the sections. For each section, the motives are given weights that indicate how often the motives appear in that section. The heaviest weight is always given to the new motive.
The 13 motives are slightly altered each time they appear in the piece. Simulating the effects of transmitting the motives over a noisy communication channel generated these alterations. Each time a motive appears, it has been modified via bit manipulation. Each motive was translated into binary representation. The representation included the duration of each note and either the starting pitch or an interval of change for each note. The translation process was performed using a Smalltalk program written by the composer. Various levels of white Gaussian noise were added to the binary stream (which was then quantized), creating errors in the representations of the motives. The addition of noise was performed using a Matlab function written by the composer's spouse. The resultant binary stream was translated to a text representation; from this representation, the composer generated the associated instrumental lines. The durations of the notes changed for each instrumental group as a whole. However, the starting pitches and intervals were free to change independently for each instrument in a group.