After months of struggling I finally managed to make a patch that mimics the effect that can be heard on Pavement’s The Hexx (from Terror Twilight). In a convincing way this time (see my previous post and laugh). This is basically a downward pitchshifter and a reverb. This patch relies heavily on Miller Puckette‘s pitchshift example (G09 in the Pd audio examples), and the idea of an impletation in Pd comes from Lorenzo Sutton.
The basic principle is simple. There is a threshold on the input. Everytime one plays a note that’s louder than this threshold, a delay gets open and lets the sound in. As soon as the loudness of the incoming sound goes back below the threshold, the delay stops being fed with the input and gets its own feedback instead (this creates a long sustain). In the meantime, whatever is in this delay line is fed into a pitchshifter that’s slowing lowering the pitch until it reaches a floor. The output of the pitchshifter is then fed into a reverb, the output of which is mixed back with the original input. Only the input and the output of the reverb can be heard.
You’ll need to set the threshold to a value that suits your instrument first. You can then play with the reverb parameters, and with the speed slider for more dramatic effects.
And of course a sound sample !