CHANGING WAVEFORMS

The tonal quality of a sound is called the timbre. The timbre of a sound is determined primarily by its "waveform." If you remember the example of throwing a pebble into the water you know that the waves ripple evenly across the pond. These waves almost look like the first sound wave we're going to talk about, the sinusoidal wave, or sine wave for short (shown below).

To make what we're talking about a bit more practical, let's go back to the first example program to investigate different waveforms. The reason for this is that you can hear the changes more easily using only one voice. LOAD the first music program that you typed in earlier, from your DATASSETTE^TM or disk, and RUN it again. That program is using the sawtooth waveform (shown here)

from the 6581 SID chip's sound generating device. Try changing the note start number in line 70 from 33 to 17 and the note stop number in line 90 from 32 to 16. Your program should now look like this: