Subharmonic

An integer submultiple or fraction of a fundamental. Whereas the harmonic series consists of integer multiples of the fundamental, the subharmonic series consists of pitches related to the fundamental by ratios: 1/2, 1/3, 1/4, 1/5, 1/6, …

Subharmonics do not normally occur in natural sounds, although the subharmonic f/2 may be generated by the cone of a loudspeaker.

Compare: Harmonic, Inharmonic, Overtone, Partial, Sideband.