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At least 667 records · Page 37Linked to original sources
PubMed1994

Modulation of fundamental frequency by laryngeal muscles during vibrato.

The variations in voice fundamental frequency (F0) that occur during vibrato production may be produced, at least in part, by modulation of laryngeal muscle activity. We have quantified this relation by using a cross-correlation analysis of the changes in F0 during vibrato and the changes either in motor unit firing rate or in gross electromyographic activity from the cricothyroid (CT) and the thyroarytenoid (TA) muscles. Two trained amateur tenors provided the data. Correlations were generally quite strong (mean r for the CT was 0.72 for singer 1 and 0.50 for singer 2; mean r for the TA was 0.31 for singer 2), thus providing support for previous evidence that fundamental frequency modulation in vibrato involves active modulation of the laryngeal motoneuron pool, especially by the CT muscle. In addition, phase delays between muscle modulation and changes in fundamental frequency were substantial (averaging approximately 130 degrees for the CT and 140 degrees for the TA). This finding may help provide insight regarding the mechanisms responsible for the production of vibrato.

Electromyography↗
PubMed1994

Relations between voice range profiles and physiological and perceptual voice characteristics in ten-year-old children.

Pitch and intensity range of 60 children were recorded and plotted in voice range profiles (VRPs). Different aspects were investigated: minimum phonation threshold, pitch range, and maximum dynamic range. Vocal fold status was determined via laryngoscopic examination. Ten percent of the children had vocal nodules, 23% glottal chinks. Seven voice experts listened to the voices recorded on two separate occasions and rated their properties along 16 parameters including hoarseness. Fourteen percent were rated as hoarse on both recordings and were thus classified as being chronically hoarse. Departures from normal in VRP characteristics were found for children suffering from chronic hoarseness, nodules, and glottal chinks. Children in general seem to have somewhat compressed VRP contours compared with adults, reflecting restricted dynamic vocal capabilities; however, children with mutational voices exhibited an approximation to adult upper VRP contours.

Auditory Perception↗
PubMed1994

Comparison of maximum flow declination rate: children versus adults.

The measure of maximum flow declination rate (MFDR) and location of MFDR provided information regarding the laryngeal mechanism's response to vocal intensity variation as a function of gender and age. Results indicate (a) increases in MFDR values as vocal intensity increases for both children and adults, and (b) higher MFDR values for men versus women and children; no gender difference was found for the children. Results for location of MFDR indicate (a) the location of MFDR to be highest for the loud-intensity production as compared with soft- and comfortable-intensity productions, and (b) the location of MFDR in women to be higher than in men. No gender difference was found for the children.

Adult↗
PubMed1994

Foreperiod duration, range, and ordering effects on acoustic LRT in normal speakers.

One quantitative measure of vocal motor control is phonation onset latency relative to presentation of an external stimulus in a reaction time task. However, variables within the design of reaction time experiments can affect laryngeal reaction time (LRT) values. The present study examines effects of foreperiod characteristics on LRT for normal speakers. Foreperiod is the interval between presentation of warning and response cues. LRT was affected by absolute foreperiod duration, by the average foreperiod duration of a block of trials, and by the ordering and range of foreperiods within a block of trials. Results are discussed with respect to foreperiod effects on the subjective expectancy and objective probability of occurrence of the response cue and on the timing of neurophysiologic processes. Control of subjective effects is critical to assessment of neurophysiologic constraints on LRT.

Adult↗
PubMed1994

Improvements in estimating the harmonics-to-noise ratio of the voice.

An improved algorithm for computing harmonics-to-noise ratio (HNR) of the voice was developed and tested using synthesized vowels at various fundamental frequencies and known HNR values. The described algorithm implements a stringent routine for the identification of pitch pulse boundary markers based on a combination of peak-picking and zero-crossing procedures. Results showed mean absolute errors between computed versus expected HNR to be < 2 dB, a significant improvement over previously reported methods. Computational errors were minimized most effectively with vowel samples in the range of 17 to -10 dB HNR. Normative data for young adult males and females indicate that HNR < 13 dB may be considered abnormal in a majority of cases.

Adult↗
PubMed1994

Average loudness level, mean fundamental frequency, and subglottal pressure: comparison between female singers and nonsingers.

Subglottal pressure, measured indirectly as the oral pressure during /p/ occlusion, was studied in 10 classically trained female singers and 10 female nonsingers, as they uttered the syllable /pa/ as softly and as loudly as possible over their entire voice ranges. There were no discernible differences between the subject groups for soft vowel phonation, but for the loudest vocalizations the singers used considerably higher subglottal pressures. Possible reasons for this difference are discussed.

Adult↗
PubMed1994

Efficacy of vocal function exercises as a method of improving voice production.

Objective voice analysis including acoustic, aerodynamic, and laryngeal videostroboscopic measures demonstrated normal voice in 35 adult women. The subjects were then randomly divided into experimental, placebo, and control groups. The experimental group engaged in vocal function exercises. The placebo group engaged in a placebo exercise program. Objective measures taken after 4 weeks of execise demonstrated significant changes in phonation volume, flow rate, maximum phonation time, and frequency range for the experimental group. No significant changes were noted in the measurements of the control and placebo groups.

Adult↗
PubMed1994

Does the voice improve with vocal hygiene education? A study of some instrumental voice measures in a group of kindergarten teachers.

This study investigated the efficacy of a program of vocal hygiene education designed for an occupational group at risk for dysphonia, namely, kindergarten teachers. Twelve female teachers explored concepts and knowledge of vocal abuse and vocal hygiene in a workshop session and attempted to practice vocal hygiene for 2 months. They showed significant voice improvement as assessed instrumentally in terms of three acoustic and electroglottographic parameters. There was no significant change of voice in a control group of 13 teachers. The results suggest that teachers were able to improve their voices if they significantly reduced vocal abuses in daily life and practiced specific strategies to maintain classroom order and reduce the use of voice in teaching.

Adult↗
PubMed1994

High-frequency components of normal and dysphonic voices.

The analysis of high-frequency energy levels can presently be considered as being more influenced by the characteristics of the speaker than by the phonetic material, serving as an indicator of the quality of the voice. In this study the energy levels in the frequency intervals of 6-10 and 10-16 kHz were evaluated, both in dysphonic voices and in subjects with no voice problems. The material consisted of consonant-vowel syllables formed by stop phonemes and the basic Spanish vowels, analyzing the vocal segment. The results indicate that the energy, found from the power spectrum average, in both frequency areas, is significantly bigger in the group with dysphonic voices. The analysis in the 10-16 kHz regions shows additional significant differences of energy between the vowels, progressively decreasing from front to back vowels.

Adult↗
PubMed1993

Physical definition of the "flageolet register".

The highest "register" of the female singing voice, often called the "flageolet register" (also called "flute register," "bell register," etc., as well as the misleading term "whistle register"), is broadly recognized by voice pedagogues, but not generally defined in terms that are adequate for objective description. This article presents a description of characteristic patterns of vocal fold movement and of vocal tract formants that are specific for the register. Measurements are made by electroglottograph, pharyngeally placed wide-band pressure transducers, and an external microphone in professional soprano subjects who are adept in using this register.

Female↗
PubMed1993

Vocal tract acoustics.

This paper considers the topic of vocal tract acoustics from the three perspectives: (a) the acoustic theory of speech production; (b) contemporary laboratory methods for acoustic analysis, and (c) measurement of the acoustic signal of speech. Linear source-filter theory is the standard acoustic theory of speech production and is the foundation for remarkable advances in the analysis and synthesis of speech. Digital signal processing, the dominant laboratory method for speech analysis, enables the acquisition and recording of the acoustic speech signal but also implements quantitative algorithms largely based on linear source-filter theory. Measurements of the acoustic signal reflect the acoustic theory of speech production, laboratory methods for signal analysis, and principles of experimental phonetics. Basic issues in the three domains of theory, laboratory methods, and measurement are summarized as they pertain to the interests of the voice scientist, voice clinician, and voice teacher.

Female↗
PubMed1993

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.

Humans↗
PubMed1993

Belting and pop, nonclassical approaches to the female middle voice: some preliminary considerations.

There is a commonly perceived difference in the sound produced in the approximate range D4-D5 by female singers in the western opera and concert tradition, on the one hand, and certain other styles, including rock, pop, folk, and some Broadway musicals, on the other. The term "belting" is sometimes used to refer to at least one approach to such "nonclassical" singing. In this study, based on spectrographic, electroglottographic, and sub- and supraglottal pressure measurements on representative voices of the "operatic" and "nonclassical" tradition, acoustic and laryngeal differences between the two traditions are described, and an objective, specific definition of "belting" is offered.

Female↗
PubMed1993

Vocal matching of frequency modulation in synthesized vowels.

Nine male singers attempted to match rates and extents of synthesized vocal vibrato at low, middle, and high pitch levels. The results showed that on average, the singers were able to match rates of 3, 5, and 7 Hz within 13%. It was difficult for the singers, however, to match extents of 0.5, 1.0, and 1.5 semitones. Thus, the results indicated singers' reasonably good ability to match rates but, contrary to prevalent opinions, not extents of vocal vibrato.

Adult↗
PubMed1996

Singing power ratio: quantitative evaluation of singing voice quality.

This paper presents a parameter for objectively evaluating singing voice quality. Power spectrum of vowel sound /a/ was analyzed by Fast Fourier Transform. The greatest harmonics peak between 2 and 4 kHz and the greatest harmonics peak between 0 and 2 kHz were identified. Power ratio of these peaks, termed singing power ratio (SPR), was calculated in 37 singers and 20 nonsingers. SPR of sung /a/ in singers was significantly greater than in nonsingers. In singers, SPR of sung /a/ was significantly greater than that of spoken /a/. By digital signal processing, power spectrum of sung /a/ was varied, and the processed sounds were perceptually analyzed. SPR had a significant relationship with perceptual scores of "ringing" quality. SPR provides an important quantitative measurement for evaluating singing voice quality for all voice types, including soprano.

Adult↗
PubMed1996

A physiological and acoustic study on voiced bilabial fricative/beta:/as a vocal exercise.

The voiced bilabial fricative/beta:/has been used as a vocal exercise. The present study investigated the effects of the exercise on voice production and voice source. This study compared vowel phonation on the syllable /a:p/ with the production of the exercise and vowel phonation before and immediately after the exercise. The methods were (a) dual-channel electroglottography, from which the vertical laryngeal position was derived, (b) electromyography using surface electrodes, and (c) inverse filtering of the acoustic signal to obtain an estimate of the voice source. In the production of /beta:/ as compared with vowel phonation in most of the cases, the vertical laryngeal position seemed to be higher, the muscular activity of the larynx lower, and the slope of the voice source spectrum steeper. In vowel phonation after the exercise, the muscular activity seemed to be lower in most cases, although the voice source remained unchanged. This seems to indicate improved vocal economy.

Electromyography↗
PubMed1996

Bifurcations in excised larynx experiments.

Bifurcation analysis was applied to vocal fold vibration in excised larynx experiments. Phonation onset and vocal instabilities were studied in a parameter plane spanned by subglottal pressure and asymmetry of either vocal fold adduction or elongation. Various phonatory regimes were observed, including single vocal fold oscillations. Selected spectra demonstrated correspondence between these regimes and vocal registers noted in the literature. To illustrate the regions spanned by the various phonatory regimes, two-dimensional bifurcation diagrams were generated. Many instabilities or bifurcations were noted in the regions of coexistence, i.e., regions in which the phonatory regimes overlap. Bifurcations were illustrated with spectrograms and fundamental frequency contours. Where possible, results from these studies were related to clinical observations.

Humans↗