This post is part of a series of notes and exercises for a summer camp on making musical instruments with Arduino and Pure Data.
The very first thing we must do this week is make noise. We’ll create this patch in Pure Data to generate a single frequency:
Follow these steps to produce your patch:
Command-Spaceto open Spotlight and type
osc~widget generates a cosine wave at a given frequency. By itself,
osc~only generates numbers—the amplitudes of the wave over time—but not any audible sound.
osc~. With this connection in place, the number shown in the box is the frequency of the generated cosine wave.
dac~—which stands for digital-to-analog converter. The job of a DAC is to turn the cosine wave into a signal that pushes the computer’s speaker in and out.
osc~to the left inlet of
dac~. You still won’t hear any sound.
After you get your patch working, answer the following questions on a piece of scratch paper.
dac~. Add a new edge from
osc~to the right inlet of
dac~. What effect does this have?