Pulsar Synthesis in Max/MSP

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28 August 2009

Pulsar Synth Interface

An implementation of granular synthesis in Max/MSP.

Pulsar synthesis is a type of granular synthesis whereby grains are ordered in time as a pulsar train. Varying the duty cycle of a pulsaret and its following silence, but maintaining the overall pulsar period gives an effect much like a band-pass filter.

In this Max/MSP patch, all parameters are available: pulsar period, pulsar duty cycle, pulsar probability and “spray”.

Pulsaret and pulsaret envelope waveforms are read from buffers allowing any arbitrary waveforms to be used. Pulsars are passed through a gate that can randomly turn each pulsar on or off, depending on the probability value. A “spray” parameter assigns each pulsar to a randomly selected output channel. The number of channels can be specified by the user.

Processing is done entirely in the audio domain allowing high frequency pulsar trains.

Simple pulsar train:

Roads (2001) suggests that transforming pulsar synthesis with convolution can lead to interesting sounds. Here is a quick example I tried.

Pulsar synthesis with convolution:

A more detailed description of pulsar synthesis can be found in:
Roads, Curtis (2001) Microsound. Cambridge: MIT Press

Example of a pulsar train waveform

Pulsar synthesis waveform

Using the pulsar~ abstraction

Pulsar synthesis Max/MSP patch

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