A Loop's A Loop's a Loop's A ...

Comments on the software by Nick Didkovsky

Wistful Reflections

I met Chuck O'Meara (then Vrtacek) in 1980, through a common friend who told me I'd probably get along with this guy who liked peculiar music. So I called up Chuck, we had a great conversation, and began improvising about once a week at his apartment in New Milford, CT. About a year later, Chuck released his first solo LP, Victory Through Grace, and I followed his lead, releasing my first LP, Now I Do This. Both of our records made use of tape loops. Chuck has released a number of solo records since then, and loops of one kind or another have appeared on most of these.

A few technical comments

This applet was written in Java, using the JMSL algorithmic music package and the JSyn realtime synthesis package. It provides the user with a virtual 8 track tape loop studio. A "found sound" paradigm is followed: you make a loop out of some tape lying around. If you like it, keep it, if you don't, toss it out and try again.

The GUI offers eight panels, each corresponding to one independent looping sound event. A JMSL "MusicShape" (which is simply an ordered list of numerical data with an instrument to play it) inhabits each panel. Each MusicShape has exactly two elements: one determining the length, loudness, and pitch of the sound, the other determining the length of the silence.

When the user clicks the start button, data is harvested from the panel and used to modify the shape data. A randomly chosen pitch within the user-selected octave is taken the Gamelan Son of Lion's tuning table (see Yudishthira's Quartet). One of three user-selected instruments is plugged into the shape as well, providing the actual timbre. These instruments were designed in JSyn. A few words about each instrument follows...
  1. Random FM
    An FM Pair with the independently randomized envelopes applied to carrier amp and to modulating amp. An additional randomized envelope controls stereo pan movement.
    Fc:Fm is randomized when the instrument is instantiated, and maintained throughout. Both Fc and Fm are integers that range from 1..10.
    Index of modulation is also randomized when the instrument is instantiated, and maintained throughout. Index is a double that ranges from 1.0 .. 25.0
    This instrument's timbre varies dramatically from instance to instance!
  2. Cheb Wave Shaper
    A WaveShaper whose transfer function (a Chebyshev polynomial) is randomized to realize between 4 and 12 harmonics, whose relative amplitudes are also chosen at random. Randomly generated envelopes are applied to the sine driving the transfer function, and to the amplitude of the waveshaper's output. An additional randomized envelope controls stereo pan movement. This instrument's sound varies, depending on the random values generated.
  3. Ringed Cheb Wave Shaper
    Like Cheb Wave Shaper, whose output is ring modulated with a sine oscillator (after Dodge/Jerse, p 142). A Fc:Fm ratio is randomized when the instrument is instantiated and maintained. Here, Fc refers to the frequency of the sine oscillator which is multiplied by the shaper, while Fm refers to the frequency of the waveshaper's sine which drives the transfer function. Again, the sound varies dramatically, with good effect!

Nick Didkovsky, July 6, 1999, NYC
A Loop's A... Home.