PLOrk fall2006/Works/Breathalyzer?

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  • composer: Matt Hoffman
  • duration: ~3'
  • software used: ChucK

Program Notes

This piece explores the potential of the built-in Apple PowerBook microphone as an expressive performance interface. Performers blow into the microphone in an attempt to control the stochastically oscillating center frequency with which a bandpass filter is applied to noise. As more "breath" is put into the laptop, the bandwidth of the filter expands, until only white noise is left.

Laptop Instructions

  • set volume to about 1/2 maximum to avoid excessive feedback
  • ensure input is set to internal mic, output to internal speakers
  • make sure nothing is plugged into the headphone jack


  • files:,,

Human Instructions


  • (ahead of time) performers are designated as either uppers or downers


  • The center frequency of your filter wants to go down - you must keep it up.


  • The center frequency of your filter wants to go up - you must keep it down.


  • Your center frequency does whatever it wants - you can only make it do so faster.


  • start,, or
  • blow into microphone until you're happy with where your filter is
  • wait until you're no longer happy/have caught your breath
  • repeat until you have no real control over the sound of your laptop
  • slowly ratchet volume down