Figure 15.5. This complex sinusoidal waveform (solid line) is generated from a
combination of three simple sine waves (dashed lines).Light can be conceptualized as a propagating vibration of an
electromagnetic field. Corresponding to the perceptual qualities of
tone and loudness for sound are the qualities of color and bright-
ness, respectively, for light.A third quality used to describe sound experience is called timbre
(Greek tympanon = drum) and is related to the complexity of the
sound waveform. A simple sinusoidal variation in pressure having a
single frequency would be experienced as a pure tone. However, most
actual air pressure variations are not single frequencies; rather, they
are complex waveforms having mixtures of several (or many) differ-
ent frequencies (Fig. 15.5).
More complex waveforms are associated with mental experiences
of sound having richness and complexity beyond that of pure tones—
this is timbre.
Musical instruments provide excellent examples of timbre (Fig.