Sten Ternström

Relationship between changes in voice pitch and loudness

Summary Changes in mean fundamental frequency accompanying changes in loudness of phonation are analyzed in 9 professional singers, 9 nonsingers, and 10 male and 10 female patients suffering from vocal functional dysfunction. The subjects read discursive texts with noise in earphones, and some also at voluntarily varied vocal loudness. The healthy subjects phonated as softly and as loudly as possible at various fundamental frequencies throughout their pitch ranges, and the resulting mean phonetograms are compared. Mean pitch was found to increase by about half-semitones per decibel sound level. Grossly, the subject groups gave similar results, although the singers changed voice pitch more than the nonsingers. The voice pitch changes may be explained as passive results of changes of subglottal pressure required for the sound level variation.

Observations of the Relationship Between Noise Exposure and Preschool Teacher Voice Usage in Day-Care Center Environments

Although the relationship between noise exposure and vocal behavior (the Lombard effect) is well established, actual vocal behavior in the workplace is still relatively unexamined. The first purpose of this study was to investigate correlations between noise level and both voice level and voice average fundamental frequency (F₀) for a population of preschool teachers in their normal workplace. The second purpose was to study the vocal behavior of each teacher to investigate whether individual vocal behaviors or certain patterns could be identified. Voice and noise data were obtained for female preschool teachers (n=13) in their workplace, using wearable measurement equipment. Correlations between noise level and voice level, and between voice level and F₀, were calculated for each participant and ranged from 0.07 to 0.87 for voice level and from 0.11 to 0.78 for F₀. The large spread of the correlation coefficients indicates that the teachers react individually to the noise exposure. For example, some teachers increase their voice-to-noise level ratio when the noise is reduced, whereas others do not.

Measuring the rate of change of voice fundamental frequency in fluent speech during mental depression

A method of measuring the rate of change of fundamental frequency has been developed in an effort to find acoustic voice parameters that could be useful in psychiatric research. A minicomputer program was used to extract seven parameters from the fundamental frequency contour of tape-recorded speech samples: (1) the average rate of change of the fundamental frequency and (2) its standard deviation, (3) the absolute rate of fundamental frequency change, (4) the total reading time, (5) the percent pause time of the total reading time, (6) the mean, and (7) the standard deviation of the fundamental frequency distribution. The method is demonstrated on (a) a material consisting of synthetic speech and (b) voice recordings of depressed patients who were examined during depression and after improvement.

A comparison of different methods to measure the EGG contact quotient

The results from six published electroglottographic (EGG-based) methods for calculating the EGG contact quotient (CQEGG) were compared to closed quotients derived from simultaneous videokymographic imaging (CQKYM). Two trained male singers phonated in falsetto and in chest register, with two degrees of adduction in both registers. The maximum difference between methods in the CQEGG was 0.3 (out of 1.0). The CQEGG was generally lower than the CQKYM. Within subjects, the CQEGG co-varied with the CQkym, but with changing offsets depending on method. The CQEGG cannot be calculated for falsetto phonation with little adduction, since there is no complete glottal closure. Basic criterion-level methods with thresholds of 0.2 or 0.25 gave the best match to the CQKYM data. The results suggest that contacting and de-contacting in the EGG might not refer to the same physical events as do the beginning and cessation of airflow.

Intonation precision of choir singers

Results from two experimental investigations on the acoustics of choirs are reported. The first concerns sound‐pressure levels (SPL) inside choirs, and the balance of loudness between a singer’s own voice and the ‘‘reference’’ sound from the rest of the choir. Long‐term SPL averages during rehearsals typically gave 80–100 dB, with little variation between choirs or with position in the choir. The fundamental frequency precision of choir singers was found to deteriorate abruptly when the reference was too loud. The influence of room acoustics and of the spacing between singers is discussed. The second investigation concerns the effect of spectral variations in the reference sound. Experiments were made primarily with individual singers under laboratory conditions. Changes in vowel quality, and absence/presence of certain partials and of vibrato, were all found to affect somewhat the degree of fundamental frequency agreement between singers. Standard deviation in fundamental frequency between section collea...

Acoustic comparison of soprano solo and choir singing

Five soprano singers were recorded while singing similar texts in both choir and solo modes of performance. A comparison of long-term-average spectra of similar passages in both modes indicates that subjects used different tactics to achieve somewhat higher concentrations of energy in the 2- to 4-kHz range when singing in the solo mode. It is likely that this effect resulted, at least in part, from a slight change of the voice source from choir to solo singing. The subjects used slightly more vibrato when singing in the solo mode.

Cancellation of Simulated Environmental Noise as a Tool for Measuring Vocal Performance During Noise Exposure

It can be difficult for the voice clinician to observe or measure how a patient uses his voice in a noisy environment. We consider here a novel method for obtaining this information in the laboratory. Worksite noise and filtered white noise were reproduced over high-fidelity loudspeakers. In this noise, 11 subjects read an instructional text of 1.5 to 2 minutes duration, as if addressing a group of people. Using channel estimation techniques, the site noise was suppressed from the recording, and the voice signal alone was recovered. The attainable noise rejection is limited only by the precision of the experimental setup, which includes the need for the subject to remain still so as not to perturb the estimated acoustic channel. This feasibility study, with 7 female and 4 male subjects, showed that small displacements of the speakers body, even breathing, impose a practical limit on the attainable noise rejection. The noise rejection was typically 30 dB and maximally 40 dB down over the entire voice spectrum. Recordings thus processed were clean enough to permit voice analysis with the long-time average spectrum and the computerized phonetogram. The effects of site noise on voice sound pressure level, fundamental frequency, long-term average spectrum centroid, phonetogram area, and phonation time were much as expected, but with some interesting differences between females and males.

Physical and acoustic factors that interact with the singer to produce the choral sound

Most of the people who perform music do so in the capacity of choir singers. An understanding of the particular acoustic properties of the choral sound is of interest not only to performers, but al ...

Toward a consensus on symbolic notation of harmonics, resonances, and formants in vocalization

Toward a consensus on symbolic notation of harmonics, resonances, and formants in vocalization

Effects of Tactile Biofeedback by a Portable Voice Accumulator on Voice Sound Level in Speakers with Parkinson's Disease

OBJECTIVES To study the effects of biofeedback on voice sound level (SL) in subjects with reduced voice SL, secondary to Parkinson disease (PD), using a portable voice accumulator. STUDY DESIGN Prospective intervention study. METHODS Voice SL, phonation time, and level of background noise were registered with a portable voice accumulator during three consecutive registration periods. Six subjects with reduced voice SL secondary to PD participated. Biofeedback, in the form of a vibration signal when voice SL went below an individually set threshold level, was administered during the second registration period only. Mean voice SL was calculated for registration periods with and without feedback. Data on phonation time and level of background noise was also collected. Field registrations with the portable voice accumulator were also compared with registrations made in a recording studio. In addition, subjects were asked about subjective experiences of using the portable voice accumulator for up to 15 days. RESULTS There was a statistically significant increase in voice SL during the period when biofeedback of voice SL was administered. Subjects reported that using the portable voice accumulator was a positive experience. Several participants wished to continue using the device. In general, subjects handled the device independently with no major problems and did not report any negative experiences. CONCLUSIONS Although this study was a first trial including six subjects with reduced voice SL secondary to PD, the findings indicate that biofeedback of voice SL administered via a portable voice accumulator may be a useful treatment tool for this group of patients and that further studies are needed.