The richness of a sound or note produced by a musical instrument is sometimes described in terms of a sum of a number of distinct
frequencies. The lowest frequency is called the
fundamental frequency and the
pitch it produces is used to name the note. For example, in western music, instruments are normally tuned to A = 440 Hz. Other significant frequencies are called
overtones of the fundamental frequency, which may include
harmonics and
partials. Harmonics are
whole number multiples of the fundamental frequency — ×2, ×3, ×4, etc. Partials are other overtones. Most western instruments produce harmonic sounds, but many instruments produce partials and
inharmonic tones, such as cymbals and other
indefinite-pitched instruments.