Formant - AbsoluteAstronomy.com

Formants are defined by Gunnar Fant

Gunnar Fant

Carl Gunnar Michael Fant was professor emeritus at the Royal Institute of Technology in Stockholm. He was a first cousin of George Fant.Gunnar Fant received a Master of Science in Electrical Engineering in 1945...

as 'the spectral peaks of the sound spectrum |P(f)|' of the voice. In speech science and phonetics

Phonetics

Phonetics is a branch of linguistics that comprises the study of the sounds of human speech, or—in the case of sign languages—the equivalent aspects of sign. It is concerned with the physical properties of speech sounds or signs : their physiological production, acoustic properties, auditory...

, formant is also used to mean an acoustic

Acoustics

Acoustics is the interdisciplinary science that deals with the study of all mechanical waves in gases, liquids, and solids including vibration, sound, ultrasound and infrasound. A scientist who works in the field of acoustics is an acoustician while someone working in the field of acoustics...

resonance

Resonance

In physics, resonance is the tendency of a system to oscillate at a greater amplitude at some frequencies than at others. These are known as the system's resonant frequencies...

of the human vocal tract. It is often measured as an amplitude peak in the frequency spectrum

Frequency spectrum

The frequency spectrum of a time-domain signal is a representation of that signal in the frequency domain. The frequency spectrum can be generated via a Fourier transform of the signal, and the resulting values are usually presented as amplitude and phase, both plotted versus frequency.Any signal...

of the sound, using a spectrogram (in the figure) or a spectrum analyzer, though in vowels spoken with a high fundamental frequency, as in a female or child voice, the frequency of the resonance may lie between the widely-spread harmonics and hence no peak is visible. In acoustics, it refers to a peak in the sound envelope and/or to a resonance in sound sources, notably musical instruments, as well as that of sound chambers. Thus it is possible to talk about the formant frequencies of a room, as exploited, for example, by Alvin Lucier

Alvin Lucier

Alvin Lucier is an American composer of experimental music and sound installations that explore acoustic phenomena and auditory perception. A long-time music professor at Wesleyan University, Lucier was a member of the influential Sonic Arts Union, which included Robert Ashley, David Behrman, and...

in his piece I Am Sitting in a Room
I Am Sitting in a Room
I am sitting in a room is one of composer Alvin Lucier's best known works, featuring Lucier recording himself narrating a text, and then playing the recording back into the room, re-recording it. The new recording is then played back and re-recorded, and this process is repeated. Since all rooms...

.

Formants and phonetics

Formants are the distinguishing or meaningful frequency components of human speech

Manner of articulation

In linguistics, manner of articulation describes how the tongue, lips, jaw, and other speech organs are involved in making a sound. Often the concept is only used for the production of consonants, even though the movement of the articulars will also greatly alter the resonant properties of the...

and of singing

Singing

Singing is the act of producing musical sounds with the voice, and augments regular speech by the use of both tonality and rhythm. One who sings is called a singer or vocalist. Singers perform music known as songs that can be sung either with or without accompaniment by musical instruments...

. By definition, the information that humans require to distinguish between vowel

Vowel

In phonetics, a vowel is a sound in spoken language, such as English ah! or oh! , pronounced with an open vocal tract so that there is no build-up of air pressure at any point above the glottis. This contrasts with consonants, such as English sh! , where there is a constriction or closure at some...

s can be represented purely quantitatively by the frequency content of the vowel sounds.
In speech, these are the characteristic partial

Overtone

An overtone is any frequency higher than the fundamental frequency of a sound. The fundamental and the overtones together are called partials. Harmonics are partials whose frequencies are whole number multiples of the fundamental These overlapping terms are variously used when discussing the...

s that identify vowels to the listener. Most of these formants are produced by tube and chamber resonance

Resonance

In physics, resonance is the tendency of a system to oscillate at a greater amplitude at some frequencies than at others. These are known as the system's resonant frequencies...

, but a few whistle tones derive from periodic collapse of Venturi effect

Venturi effect

The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section of pipe. The Venturi effect is named after Giovanni Battista Venturi , an Italian physicist.-Background:...

low-pressure zones. The formant with the lowest frequency is called f₁, the second f₂, and the third f₃. Most often the two first formants, f₁ and f₂, are enough to disambiguate the vowel. These two formants determine the quality of vowels in terms of the open/close and front/back dimensions (which have traditionally, though not entirely accurately, been associated with the position of the tongue). Thus the first formant f₁ has a higher frequency for an open vowel (such as [a]) and a lower frequency for a close vowel (such as [i] or [u]); and the second formant f₂ has a higher frequency for a front vowel (such as [i]) and a lower frequency for a back vowel (such as [u]). Vowels will almost always have four or more distinguishable formants; sometimes there are more than six. However, the first two formants are most important in determining vowel quality, and this is often displayed in terms of a plot of the first formant against the second formant, though this is not sufficient to capture some aspects of vowel quality, such as rounding.

Nasals usually have an additional formant around 2500 Hz. The liquid [l] usually has an extra formant at 1500 Hz, while the English

English language

English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...

"r" sound ([ɹ]) is distinguished by virtue of a very low third formant (well below 2000 Hz).

Plosives (and, to some degree, fricatives

Fricative consonant

Fricatives are consonants produced by forcing air through a narrow channel made by placing two articulators close together. These may be the lower lip against the upper teeth, in the case of ; the back of the tongue against the soft palate, in the case of German , the final consonant of Bach; or...

) modify the placement of formants in the surrounding vowels. Bilabial sounds (such as 'b' and 'p' as in "ball" or "sap") cause a lowering of the formants; velar

Velar consonant

Velars are consonants articulated with the back part of the tongue against the soft palate, the back part of the roof of the mouth, known also as the velum)....

sounds ('k' and 'g' in English) almost always show f₂ and f₃ coming together in a 'velar pinch' before the velar and separating from the same 'pinch' as the velar is released; alveolar

Alveolar consonant

Alveolar consonants are articulated with the tongue against or close to the superior alveolar ridge, which is called that because it contains the alveoli of the superior teeth...

sounds (English 't' and 'd') cause less systematic changes in neighboring vowel formants, depending partially on exactly which vowel is present. The time-course of these changes in vowel formant frequencies are referred to as 'formant transitions'.

If the fundamental frequency of the underlying vibration is higher than a resonance frequency of the system, then the formant usually imparted by that resonance will be mostly lost. This is most apparent in the example of soprano

Soprano

A soprano is a voice type with a vocal range from approximately middle C to "high A" in choral music, or to "soprano C" or higher in operatic music. In four-part chorale style harmony, the soprano takes the highest part, which usually encompasses the melody...

opera

Opera

Opera is an art form in which singers and musicians perform a dramatic work combining text and musical score, usually in a theatrical setting. Opera incorporates many of the elements of spoken theatre, such as acting, scenery, and costumes and sometimes includes dance...

singers, who sing high enough that their vowels become very hard to distinguish.

Control of resonances is an essential component of the vocal technique known as overtone singing

Overtone singing

Overtone singing, also known as overtone chanting, or harmonic singing, is a type of singing in which the singer manipulates the resonances created as air travels from the lungs, past the vocal folds, and out the lips to produce a melody.The partials of a sound wave made by the human voice can be...

, in which the performer sings a low fundamental tone, and creates sharp resonances to select upper harmonics, giving the impression of several tones being sung at once.

Spectrogram

Spectrogram

A spectrogram is a time-varying spectral representation that shows how the spectral density of a signal varies with time. Also known as spectral waterfalls, sonograms, voiceprints, or voicegrams, spectrograms are used to identify phonetic sounds, to analyse the cries of animals; they were also...

s are used to visualise formants.

**Vowel formant centers**
Vowel (IPA International Phonetic Alphabet The International Phonetic Alphabet "The acronym 'IPA' strictly refers [...] to the 'International Phonetic Association'. But it is now such a common practice to use the acronym also to refer to the alphabet itself that resistance seems pedantic... )	Formant f₁	Formant f₂
u	320 Hz	800 Hz
o	500 Hz	1000 Hz
ɑ	700 Hz	1150 Hz
a	1000 Hz	1400 Hz
ø	500 Hz	1500 Hz
y	320 Hz	1650 Hz
ɛ	700 Hz	1800 Hz
e	500 Hz	2300 Hz
i	320 Hz	2500 Hz

**Vowel formants**
Vowel	Main formant region
u	200–400 Hz
o	400–600 Hz
a	800–1200 Hz
e	400–600 and 2200–2600 Hz
i	200–400 and 3000–3500 Hz

Singers' formant

Studies of the frequency spectrum of trained singers

Singing

, especially male singers, indicate a clear formant around 3000 Hz (between 2800 and 3400 Hz) that is absent in speech or in the spectra of untrained singers. It is thought to be associated with one or more of the higher resonances of the vocal tract. It is this increase in energy at 3000 Hz which allows singers to be heard and understood over an orchestra

Orchestra

An orchestra is a sizable instrumental ensemble that contains sections of string, brass, woodwind, and percussion instruments. The term orchestra derives from the Greek ορχήστρα, the name for the area in front of an ancient Greek stage reserved for the Greek chorus...

, which peak at much lower frequencies of around 500 Hz. This formant is actively developed through vocal training

Vocal pedagogy

Vocal pedagogy is the study of the art and science of voice instruction. It is used in the teaching of singing and assists in defining what singing is, how singing works, and how proper singing technique is accomplished....

, for instance through so-called "voce di strega" or witch's voice exercises and is caused by a part of the vocal tract acting as a resonator.

External links

Formants for fun and profit
Formants and wah-wah pedals
What is a formant? A discussion of the three different meanings of the word 'formant'
Formant tuning by soprano singers from the University of New South Wales
The acoustics of harmonic or overtone singing from the University of New South Wales
Materials for measuring and plotting vowel formants
Acoustics of the Vowel A discussion of possible formant variations without affection of the phoneme identity.

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Formants and phonetics

Singers' formant

See also

External links