Measurement of formant frequencies and bandwidths in singing

That singers under certain circumstances adjust the articulation of the vocal tract (formant tuning) to enhance acoustic output is both apparent from measurements and understood in theory. The precise effect of a formant on an approaching (retreating) harmonic as the latter varies in frequency during actual singing, however, is difficult to isolate. In this study variations in amplitude of radiated sound components as well as supraglottal and subglottal (esophageal) pressures accompanying the vibrato-related sweep of voice harmonics were used as a basis for estimating the effective center frequencies and bandwidths of the first and second formants.     

Formant frequency tuning in singing

It is sometimes claimed that some singers tune their two lowest formant frequencies to harmonic partials in order to increase the audibility of the voice. Voice acoustics predicts that such tuning of formants should cause vowel quality to change. Using a newly constructed digital singing machine, the authors have explored the perceptual consequences of such tuning. Four different cases were represented, in which the two lowest formant frequencies were either constant or adapted to the fundamental frequency according to either of three different strategies. The resulting voice timbres were judged by an expert panel of singing teachers in a listening test consisting of descending chromatic scales. Constant formant frequencies were clearly preferred, presumably because formant tuning entails formant frequency shifts between adjacent tones so substantial that salient vowel quality shifts occur.     

Formant frequencies in Estonian folk singing.

Formant frequencies in an old Estonian folk song performed by two female voices were estimated for two back vowels /a/ and /u/, and for two front vowels /e/ and /i/. Comparison of these estimates with formant frequencies in spoken Estonian vowels indicates a trend of the vowels to be clustered into two sets of front and back ones in the F1/F2 plane. Similar clustering has previously been shown to occur in opera and choir singing, especially with increasing fundamental frequency. The clustering in the present song, however, may also be due to a tendency for a mid vowel to be realized as a higher-beginning diphthong, which is characteristic of the North-Estonian coastal dialect area where the singers come from. No evidence of a "singer's formant" was found.     

Respiratory function during speaking and singing in professional country singers

Respiratory function during speaking and singing was investigated in six male professional country singers. Function was studied using magnetometers to transduce anteroposterior diameter changes of the rib cage and abdomen while subjects performed various respiratory maneuvers, speaking activities, and singing activities. Results indicated that respiratory behavior during speaking was generally the same as that of other normal subjects. Respiratory behavior during singing resembled that of speaking. Discussion includes comparison of respiratory performance of present singers with untrained singers and classically trained singers. Implications are offered regarding how the results might be applied to the prevention of voice disorders by education and training of country singers.     

Formant frequency analysis of children''s spoken and sung vowels using sweeping fundamental frequency production

High-pitched productions present difficulties in formant frequency analysis due to wide harmonic spacing and poorly defined formants. As a consequence, there is little reliable data regarding children's spoken or sung vowel formants. Twenty-nine 11-year-old Swedish children were asked to produce 4 sustained spoken and sung vowels. In order to circumvent the problem of wide harmonic spacing, F₁ and F₂ measurements were taken from vowels produced with a sweeping F₀. Experienced choir singers were selected as subjects in order to minimize the larynx height adjustments associated with pitch variation in less skilled subjects. Results showed significantly higher formant frequencies for speech than for singing. Formants were consistently higher in girls than in boys suggesting longer vocal tracts in these preadolescent boys. Furthermore, formant scaling demonstrated vowel dependent differences between boys and girls suggesting non-uniform differences in male and female vocal tract dimensions. These vowel-dependent sex differences were not consistent with adult data.     

Breathing for singing

Methods of teaching breathing for singers are diverse. However, it is universally agreed that breath training and support are essential to good singing technique. One method is presented in detail to illustrate the difficulties in producing good singing technique in the studio and the need for imagery as well as scientific fact. The need for further collaboration among scientists and voice teachers is stressed.     

Comparisons of pharynx, source, formant, and pressure characteristics in operatic and musical theatre singing

Belting, a vocal technique typically cultivated in musical theatre singing, differs timbrally from operatic singing in many interesting respects. The underlying phonatory differences have not been previously investigated in detail. Yet, belting is frequently associated with disturbances of voice function. Articulatory and phonatory characteristics are investigated in a female subject who is a professional singer (co-author JL) trained in both the operatic and belting styles and in an intermediate vocal technique (“mixed”). This article presents data obtained from this subject by video-fiberoptic observation of the pharynx, inverse filtering of airflow, and measurement of subglottal pressure. The results reveal that belting was characterized by very high subglottal pressures and sound levels, and apparently also by a comparatively high degree of glottal adduction. Comparisons with other investigations of related aspects of belting and operatic singing support the assumption that the data obtained from our subject are representative for these vocal techniques.     

Overtone singing: Productive mechanisms and acoustic data

Overtone singing is where one person sings in two voices, the first voice represented by the fundamental and the second by an enhanced harmonic. Overtone singing is performed in chest register. Tuning of the first or second formant and a reduction of the formant bandwidth down to 20 Hz make harmonics prominent. Narrowing the pharynx, velar constriction, variation of the small mouth opening, and a tension of the walls of the mouth cavity are used. Changing prominent harmonics has the effect of creating an overtone melody with sustained tones, tone steps, and trillos.     

Dependence of jaw opening on pitch and vowel in singers

In singing, F₀ sometimes is much higher than the typical frequency value of F₁. According to previous investigations, sopranos raise F₁ to a frequency near F₀ by widening the jaw opening in such cases. In the present study, the jaw opening was measured in 10 professional singers of different categorizations whose task was to sing an ascending two-octave scale on different vowels. Their normal F₁ values for these vowels were determined at a low F₀. Only for the vowels /a/ and /a/ did the singers widen the jaw opening when F₀ approached the F₁ value measured at a low pitch. For the other vowels, jaw opening was widened, beginning at a higher F₀. It is assumed that for these vowels the singers used other articulatory means to increase F₁.     

The Relative Contributions of Speaking Fundamental Frequency and Formant Frequencies to Gender Identification Based on Isolated Vowels

The purpose of this study was to determine the accuracy with which listeners could identify the gender of a speaker from a synthesized isolated vowel based on the natural production of that speaker when (1) the fundamental frequency was consistent with the speaker's gender, (2) the fundamental frequency was inconsistent with the the speaker's gender, and (3) the speaker was transgendered. Ten male-to-female transgendered persons, 10 men and 10 women, served as subjects. Each speaker produced the vowels /i/, /u/, and //. These vowels were analyzed for fundamental frequency and the first three formant frequencies and bandwidths. Formant frequency and bandwidth information was used to synthesize two vowel tokens for each speaker, one at a fundamental frequency of 120 Hz and one at 240 Hz. Listeners were asked to listen to these tokens and determine whether the original speaker was male or female. Listeners were not aware of the use of transgendered speakers. Results showed that, in all cases, gender identifications were based on fundamental frequency, even when fundamental frequency and formant frequency information was contradictory.     

Perceived pitch of whispered vowels-relationship with formant frequencies: A preliminary study

To clarify the role of formant frequency in the perception of pitch in whispering, we conducted a preliminary experiment to determine (1.) whether speakers change their pitch during whispering; (2.) whether listeners can perceive differences in pitch; and (3.) what the acoustical features are when speakers change their pitch. The listening test of whispered Japanese speech demonstrates that one can determine the perceived pitch of vowel /a/ as ordinary, high, or low. Acoustical analysis revealed that the perception of pitch corresponds to some formant frequencies. Further data with synthesized whispered voice are necessary to confirm the importance of the formant frequencies in detail for perceived pitch of whispered vowels.     

Feedback from spectrum analysis applied to the singing voice

Despite the general availability in the past two decades of the spectrum analyzer and prominent pedagogical theories concerning the conscious tuning of vowel formants to enhance the singing voice, there has been little reported use of spectrum analysis to track formant frequencies in singing. An important exception is Sundberg's work (1) on the soprano voice. The reasons for this neglect are considered: in the singing range where information on formant tuning would be most helpful, the wide spacing of the harmonics renders the formants difficult to locate by spectrum analysis. Methods are described for obtaining continuous spectrograms with the vocal tract in the varied articulations of singing by using sweep tones and nonharmonic voice sources, and thus locating quickly and accurately the frequencies of the first five formants.     

The singing/acting child: a speech-languagepathologist''s perspective

Performance-oriented children who encounter voice problems benefit from a team approach to intervention. Developmental and psychosocial issues in addition to the acquisition of information and vocal skills must be addressed. This article presents information from a speech-language pathologist's perspective and includes some examples of clinical approaches and strategies. The importance of building motivation to change vocal habits and the need for the child to develop insight and self-evaluation strategies is emphasized.     

Formant frequencies, bandwidths, and Qs in helium speech

We used linear prediction analysis to estimate a diver's vocal tract response for isolated vowels spoken in air at 1 atm and in heliox at simulated depths of 54-, 120-, 300-, and 500-m seawater. We specifically measured formant frequency, bandwidth, and Q changes as a function of environment. The formant frequencies shifted upward nonlinearly in helium speech. The formant bandwidths in helium speech increased as much as 14 times their corresponding bandwidths in normal speech. The ratios of formant Qs (helium speech to normal speech) ranges from 0.3 (low formants) to 2 (high formants).     

Movement of the velum during speech and singing in classically trained singers

The present study addresses two questions: (a) Is the action and/orposture of the velopharyngeal valve conducive to allow significant resonance during Western tradition classical singing? (b) How do the actions of the velo-pharyngeal valve observed in this style of singing compare with normal speech? A photodetector system was used to observe the area function of the velopharyngeal port during speech and classical style singing. Identical speech samples were produced by each subject in a normal speaking voice and then in the low, medium, and high singing ranges. Results indicate that in these four singers the velopharyngeal port was closed significantly longer in singing than in speaking samples. The amount of time the velopharyngeal port was opened was greatest in speech and diminished as the singer ascended in pitch. In the high voice condition, little or no opening of the velopharyngeal port was measured.     

Potential factors related to untrained singing talent: a survey of singing pedagogues

A national survey was conducted to identify factors associated with untrained singing talent based on perceptions obtained from a homogeneous group of professional singing pedagogues. Survey items included questions related to the perception of singing talent, factors associated with untrained singing talent, and physiological variables that distinguished untrained singing talented individuals from those without obvious singing talent. The survey data suggested that intonation, timbre, and musicality were rated the most important factors associated with the perception of singing talent in an untrained individual. Environmental influences and genetics were rated most important for explaining why one individual would express singing talent and another would not. In addition, the data suggested that abilities related to the control of pitch distinguished untrained talented individuals from those without singing talent more than other physiological variables.     

What is “Twang”?

A single female professional vocal artist and pedagogue sang examples of “twang” and neutral voice quality, which a panel of experts classified, in almost complete agreement with the singer's intentions. Subglottal pressure was measured as the oral pressure during the occlusion during the syllable /pae/. This pressure tended to be higher in “twang,” whereas the sound pressure level (SPL) was invariably higher. Voice source properties and formant frequencies were analyzed by inverse filtering. In “twang,” as compared with neutral, the closed quotient was greater, the pulse amplitude and the fundamental were weaker, and the normalized amplitude tended to be lower, whereas formants 1 and 2 were higher and 3 and 5 were lower. The formant differences, which appeared to be the main cause of the SPL differences, were more important than the source differences for the perception of “twanginess.” As resonatory effects occur independently of the voice source, the formant frequencies in “twang” may reflect a vocal strategy that is advantageous from the point of view of vocal hygiene.