Formant

In speech science and phonetics, a formant is the broad spectral maximum that results from an acoustic resonance of the human vocal tract.[1][2] In acoustics, a formant is usually defined as a broad peak, or local maximum, in the spectrum.[3][4] For harmonic sounds, with this definition, the formant frequency is sometimes taken as that of the harmonic that is most augmented by a resonance. The difference between these two definitions resides in whether "formants" characterise the production mechanisms of a sound or the produced sound itself. In practice, the frequency of a spectral peak differs slightly from the associated resonance frequency, except when, by luck, harmonics are aligned with the resonance frequency.

Spectrogram of American English vowels [i, u, ɑ] showing the formants F1 and F2

A room can be said to have formants characteristic of that particular room, due to its resonances, i.e., to the way sound reflects from its walls and objects. Room formants of this nature reinforce themselves by emphasizing specific frequencies and absorbing others, as exploited, for example, by Alvin Lucier in his piece I Am Sitting in a Room.

In both speech and rooms, formants are characteristic features of the resonances of the space. They are said to be excited by acoustic sources such as the voice, and they shape (filter) the sources’ sounds, but they are not sources themselves.


Share this article:

This article uses material from the Wikipedia article Formant, and is written by contributors. Text is available under a CC BY-SA 4.0 International License; additional terms may apply. Images, videos and audio are available under their respective licenses.