subtone

Subtone is a term used in acoustics, music, and audio production to denote a tone or frequency component that lies below a reference pitch. In common usage, subtone can refer to a low-frequency element that shapes the perceived depth and timbre of a sound, or, in technical contexts, to subharmonics produced by nonlinear systems. The term is sometimes used interchangeably with undertone, though some fields distinguish subharmonics (fractions of the fundamental) from subtone concepts.

In the analysis of sounds, a spectrum may contain subtones when a sound contains energy at frequencies below the intended or fundamental pitch. Subtones can arise from physical nonlinearities in vibrating bodies or from electronic processing. They differ from overtones and harmonics, which lie above the fundamental.

In performance and synthesis, subtone is used to describe both a musical effect and a tonal quality. Some wind or vocal techniques emphasize a low, breathy, or intimate sound described as a subtone. In electronic music and synthesis, sub-octave or sub-bass tones are generated to extend the low end of a sound, often labelled as subtone components.

The term is not uniformly defined across disciplines; practitioners may describe subtone elements as undertones, subharmonics, or simply low-frequency components depending on context. In scholarly writing, precise terms such as subharmonic, undertone, or low-frequency component are preferred for clarity.

See also: subharmonic, undertone, sub-bass, harmonic series.