Waveform? Brightness?

I just got a Moog Etherwave theremin. I know what the pitch and volume controls do, but what exactly do the waveform and brightness controls do?

The waveform changes the type of waveform that the theremin outputs.

The brightness is basically a filter - think of it as analogous to a "treble" knob on a stereo.

The best way to understand what the knobs do is to experiment with them - it will explain more than we can do in words alone.

This website explains all:

http://www.electrotheremin.com/Topic-sound.html