Languages & Linguistics
Formant
Formants are resonant frequencies in the vocal tract that contribute to the distinct sounds of vowels and consonants in human speech. They are created by the shaping of the vocal tract and are crucial for distinguishing between different speech sounds. Formants play a key role in the study of phonetics and are used to analyze and understand the acoustic properties of speech sounds.
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6 Key excerpts on "Formant"
- Yunqiu Zhang(Author)
- 2019(Publication Date)
- Routledge(Publisher)
The appearance of this vocal difference between men and women also becomes an important symbol of biological matu-rity. During the adult stage, after voice change (Stage III of F0 development G5–8), gender differences are still substantially manifested in the development of fundamental frequency. 2.4 The development of Formants in primary vowels The most important manifestations of vowels from an acoustic perspective are Formant frequencies and Formant patterns. Different from fundamental frequency, Formant frequency illustrates the characteristics of vocal tract transmission (also known as the acoustic resonance of the vocal tract). It is created by the resonance of the vocal cavities and is a passive frequency that depends on physiological characteristics, such as the shape and volume of the vocal organ. Generally, it is believed that the three following physiological factors constrain the characteris-tics of Formants: I first one is the position of the point of maximum constriction. This constriction point divides the vocal tract into anterior and posterior tubes, which are controlled by the forward and backward movement of the tongue and correspond to the anterior and posterior positions of models of tongue position -ing. The second is the size of the cross-sectional area at the point of maximum constriction. This is controlled by how far the tongue moves in relation to the top of the oral cavity and the back of the pharynx and roughly resembles the height of the tongue in regard to models of tongue positioning. The third is the position of the lips, which is the area of the lip shape (Ladefoged, 1996). In addition, the length of the vocal tract itself is also an important constraining factor (Bao, 1984).
eBook - PDFSociophonetics
An Introduction
- Erik Thomas(Author)
- 2017(Publication Date)
- Red Globe Press(Publisher)
Formants aren’t just properties of vowels, though. They’re critical for conso-nants as well. Consonant place of articulation is indexed by the Formant pat-terns of the transitions between a consonant and neighbouring vowels. Many of the approximants look like vowels on spectrograms, with full-fledged Formant structures. Formants also appear in aspiration and frication, and to an extent in bursts. Hence, Formant measurement is just as much a part of consonantal analysis as it is part of vocalic analysis. Formant analysis plays a marginal role in prosodic analysis in that vowel reduction is related to stress patterns. It inter-faces with voice quality, too, such as for nasality. Formant analysis is covered here because its applications are so general. A few words of caution about Formant measurement are in order. First, although acoustic measurement is useful for a wide range of vowel analyses, it’s not necessary for all studies. For some studies, impressionistic transcription is quite adequate. Second, bear in mind that any measurement of a Formant is an estimate – it isn’t really possible to determine a Formant value exactly. In addition, not every variation visible in a spectrogram is relevant for lectal varia-tion. Missing the forest for the trees is easy to do. Furthermore, you have to be careful not to take faulty measurements. The following sections will show you how to analyse consonant transitions and vowels acoustically and how to avoid pitfalls that result in bad measurements. Linear predictive coding (LPC) Today, software programs that estimate centre frequencies of Formants nearly always do so by means of a process called linear predictive coding , or LPC . LPC became the standard tool for estimating Formant frequencies after the influ-ential publications of Atal and Hanauer (1971) and Markel and Gray (1976).
eBook - PDF- Jan Awrejcewicz(Author)
- 2014(Publication Date)
- IntechOpen(Publisher)
We can model the acoustic properties of the vocal tract as a tube open at one end, which is the mouth, and closed at the glottis. Assuming this tube uniformity, resonant frequencies can be calculated with the following formula: F n = ( 2 n -1 ) c 4 L , (1) where n is the number of the Formant, c is the speed of sound, and L is the length of the tube. However, we also need to consider acoustic constrictions in the vocal tract. One way of modelling the acoustic properties of vowels is to represent the vocal tract as a concatenation of tubes [16]. An alternative approach is known as perturbation theory, which deals with vocalic acoustics in terms of relationship between air pressure and speed [17]. 3.1. Formant frequencies of the vowels First Formant frequency ( F 1) is traditionally influenced by the shape of the vocal tract. F 1 is inversely related to tongue height: low vowels have high F 1 and high vowels have low Spectral Study with Automatic Formant Extraction to Improve Non-native Pronunciation of English Vowels http://dx.doi.org/10.5772/57221 331 F 1. On the other hand, second Formant frequency ( F 2) corresponds to length and size of the speaker’s oral cavity; in this case, front vowels have high F 2 whereas back vowels have low F 2; the Formant frequencies decrease through the cardinal vowels, where the cardinal vowels can be consulted at [18]. Nevertheless, these relationships are not straightforward since there are other factors influencing sound production (e.g. lip rounding, tongue retroflexion, among others). Articulatory properties of vowels are determined by these F 1 and F 2 Formants in such a way that one is plotted against the other. Because of the inverse relationship between articulatory parameters and Formant frequencies, zero frequency is at the top right corner. In Fig. 2 [1], we have displayed where English vowels are pronounced inside the oral cavity: Figure 2.
eBook - PDF- Diana Deutsch(Author)
- 2013(Publication Date)
- Academic Press(Publisher)
Incidentally, the same result was found by Cole-man (1976) in a study of maleness and femaleness in voice timbre. The result is not very surprising if we assume that we rely mainly on the most apparent acoustic characteristic in this classification task. By comparing vowels sung at the same pitches, Cleveland found that the Formant frequencies serve as a secondary cue. The trend was that the lower the Formant frequencies, the lower the pitch range the singer is assumed to possess. In other words, low Formant frequencies seem to be associated with bass singers and high Formant frequencies with tenors. In a subsequent listening test Cleveland verified these results by presenting the same singing teachers with vowels synthesized with Formant frequencies that were varied systematically in ac-cordance with his results obtained from real vowel sounds. Cleveland also speculated about the morphological background of these findings. As has been described, Formant frequencies are determined by the dimensions of the vocal tract. These dimensions are smaller in children and females than in male adults, and the Formant frequencies differ accordingly. As a longer tube resonator has lower resonance frequencies than a shorter tube, the Formant frequencies produced by a male tend to be lower than those produced by a female for a given vowel. The female vocal tract is not simply a small-scale copy of the male vocal tract (Fant, 1973). The pharynx-to-mouth length ratio is smaller in females than in males. The acoustic consequence is that certain Formant frequencies in certain vowels exhibit greater differences between sexes than others, as can be seen in Fig. 9 (see also Nordstrom, 1977). The greatest variations are found in the two lowest Formant frequencies. In the same figure are shown the corresponding values that Cleveland found when he com-pared a tenor voice with a bass voice.
eBook - PDFAcoustic Theory of Speech Production
With Calculations based on X-Ray Studies of Russian Articulations
- Gunnar Fant(Author)
- 2012(Publication Date)
- De Gruyter Mouton(Publisher)
The extreme example of an intuitive construction of Formant-cavity affiliations, in part compiled from earlier suggestions in the literature, is the physiological classification system of Sovijärvi (1938a,b) involving a large number of Formants and corresponding subcavities or regions within the vocal tract (seven variable and eleven fixed). Parts of this system are a product of in-complete acoustic theory but some statements, e.g., concerning the larynx tube resonance, are supported by the present work. Other statements, e.g., concerning nasal resonances and the trachea resonance, are in part correct or deserve a closer investigation. A strikingly simple theory for the interrelation of F,Fi, and F 3 has been proposed by Ganeshsundaram (1957). His cascade modulation theory suggests that F 3 — F 2 is constantly equal to 2F U so that F¡ would be an upper and F 2 a lower side-band located plus and minus F¡ relative to a mouth cavityresonance F{, the latter suppressed in amplitude. Quite apart from the unrealistic physical theory, which is upset by the basic principle of 114 Calculations Based on X-Ray Data It is the purpose of this section to supplement the more general theories of vocal tract models developed in Chapters A.3 and 1.4 with a study of the main physiological and acoustic facts concerning the production of the six Russian vowels studied in this work. Among questions of particular interest are the validity of the double Helmholtz resonator theory and the applicability of the three-parameter nomograms of Section 1.43 B. Quantitative expressions for the relative role of any particular part of the vocal tract as a determinant of each of the Formants will be dealt with in some detail. Table 2.33-1 Β summarizes the articulatory data extracted from the vocal tract area functions of Fig. 2.3-2. The good agreement between calculated and actually measured Formant frequencies from tape-recordings of the subject shown in Fig.
eBook - PDF- Alan Cruttenden(Author)
- 2014(Publication Date)
- Routledge(Publisher)
But we can an modify the glottal tone so as to produce vowels as different as [i:] and [a:], so that despite our divergences of voice quality we can convey the distinction between two words such as key and car. This variation of quality, or timbre, of the glottal tone is achieved by the shapes which we give the resonators above the larynx-the pharynx, the mouth and the nasal cavities. These chambers are capable of assuming a very large number of shapes, each of which will have a characteristic vibrating resonance of its own. Those harmonics of the glottal tone which coincide with the chamber's own resonance are very considerably amplified. Thus, certain bands of strongly reinforced harmonics are characteristic 20 Language and speech of a particular arrangement of the resonating chambers which produces, for instance, a certain vowel sound. Moreover, these bands of frequencies will be reinforced whatever the fundamental frequency. In other words, whatever the pitch on which we say, for instance, the vowel [u:], the shaping of the resonators and their resonances will be very much the same, so that it is still possible, except on extremely high or low pitches, to recognise the quality intended. It is found that, for male speakers, the vowel [ir] has one such characteristic band of strong components in the region of 280 Hz and another at about 2,200 Hz, while for female speakers these bands of energy are at about 300 Hz and 2,700 Hz (see §8.6). 3.2 The acoustic spectrum This complex range of frequencies of varying intensity which go to make up the quality of asound is known as the ACOUSTIC SPECTRUM, those bands of energy which are characteristic of a particular sound are known as the sound's FormantS. Thus, Formants of [u:] are said to occur, for female speakers, in the regions around 700 and 1,300 Hz. Such complex waveforms can be analysed and displayed as a SPECTROGRAM (see Fig. 3).
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