Game Development Reference
In general, sound waves don't look like the pure harmonic wave shown in Figure 26-4
unless the sound is a pure tone. A non-pure tone will have other wiggles in its plot
resulting from components at other frequencies and phases. Similarly, if you record the
sound pressure at a single point in a room, for example, where multiple sound sources
exist, the pressure recording at the point in question will not correspond to the sound
of any particular sound source. Instead, the recorded pressure time history will be some
combination of all the sources present, and what you hear is some combination of all
the sound sources.
A good approximation for how these various sound components combine is simply to
sum the results of each component at the particular point in question. This is the prin‐
ciple of superposition.
Figure 26-5 shows 10 different waveforms, each with different amplitudes, frequencies,
and phases. The principle of superposition says that we can add all these waveforms to
determine the combined result.
Figure 26-5. Ten different waves