I originally wrote this for a guitar quartet with Keith Rowe, Hans Tammen, Erhard Hirt, and myself. We performed this in Budapest in 2007. This version is for solo performer (music minus three?)
The appearance/disappearance of a symbol on the computer screen tells me when to play and when not to play. Similarly, three virtual players are being turned on and off (my symbol is on the top left, theirs are in the other three quadrants ). These virtual players are playing back by choosing samples of my real-time guitar performance.
The symbols turn on and off according to an Event Density value (number of events per minute). These density changes over time... for example, they can go from very sparse (short events, only a few per minute) to densities fast enough that they are heard as rhythmic. How these densities change over time from one value to another are specified by different interpolators. So one player might go from 2 events per minute to 60 events per minute following a linear interpolator, while another may have the same endpoints but use a half cosine interpolator. So this piece is a study of how these densities can change over time, and at times congeal the four performers into unity, at other times disperse their performance into an uncorrelated smear and the trajectory between these states (which is why it's entitled "Density Trajectory Study")
I've got a big record buffer in JMSL/JSyn into which I am constantly sending the guitar signal. The software segments the buffer into chunks it recognizes as contiguous, and uses these segments as material for the three virtual players to use. At a couple of moments you can see a screenshot of the system selecting these segments for playback (vertical flashing yellow rectangles highlighting green rectangular audio segments, at times 1:36 and 5:04)