The quality of a musical sound that distinguishes one musical instrument
from another is called timbre
. Timbre is due in part to the fact
that musical instruments do not produce purely sinusoidal sounds. Instead,
to a first approximation, they produce sounds that consist of a fundamental
sinusoidal component and harmonics
. The fundamental is at the frequency
of the note being played, and the harmonics are at multiples of that frequency.
In the following applet, you can adjust the relative weighting of the fundamental
and harmonics for a musical sound.