Editing Formant (section)

{{Short description|Spectrum of phonetic resonance in speech production}}
[[Image:Spectrogram -iua-.png|250px|thumb|[[Spectrogram]] of American English vowels {{IPA|[i, u, ɑ]}} showing the formants ''F''<sub>1</sub> and ''F''<sub>2</sub>]]
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In [[speech science]] and [[phonetics]], a '''formant''' is the broad spectral maximum that results from an [[acoustic resonance]] of the [[Vocal tract|human vocal tract]].<ref>Titze, I.R. (1994). Principles of Voice Production, Prentice Hall, {{ISBN|978-0-13-717893-3}}.</ref><ref>Titze, I.R., Baken, R.J. Bozeman, K.W., Granqvist, S. Henrich, N., Herbst, C.T., Howard, D.M., Hunter, E.J., Kaelin, D., Kent, R.D., Löfqvist, A., McCoy, S., Miller, D.G., Noé, H., Scherer, R.C., Smith, J.R., Story, B.H., Švec, J.G., Ternström, S. and Wolfe, J. (2015) "Toward a consensus on symbolic notation of harmonics, resonances, and formants in vocalization." J. Acoust. Soc. America. 137, 3005–3007.</ref> In [[acoustics]], a formant is usually defined as a broad peak, or local maximum, in the spectrum.<ref>Jeans, J.H. (1938) Science & Music, reprinted by Dover, 1968.</ref><ref>Standards Secretariat, Acoustical Society of America, (1994). ANSI S1.1-1994 (R2004) American National Standard Acoustical Terminology, (12.41) Acoustical Society of America, Melville, NY.</ref> 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, or when the sound source is mostly non-harmonic, as in whispering and [[Vocal fry register|vocal fry]].

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 acoustic [[digital signal processing]], the way a collection of formants (such as a room) affects a signal can be represented by an [[impulse response]].

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.