Here is an example of a trivial additive synthesis. introscale.sco plays a simple major scale. introscales.orc defines the "instrument" on which the scale is played by summing 2 sine waves, and modulating the amplitude with a piecewise-linear envelope. The main purpose of this example is to give you a schema that you may edit to produce more realistic sounds by additive synthesis. But, there are a few interesting things about the example itself. Try to figure out the relation between the frequencies of the sine waves, and the pitches of the notes that you hear. It is not quite obvious.