Phonational profiles of female professional singers and nonsingers

Measures of the SFF, vocal intensity, phonational range, and habitualpitch level are reported for 39 professional singer and 39 nonsinger females, who were divided into three age groups (young, middle, and old age), with the professionals further divided into sopranos and altos. Each read the “Rainbow Passage” and spoke extemporaneously, from which measures of the SFF and vocal intensity were calculated; phonational range and habitual pitch levels were also determined. No significant differences were noted between the reading and speaking tasks. The SFF and intensity levels were significantly higher for the professionals in comparison to the nonsingers, but only for certain age groups. Moreover, whereas the nonsinger SFF levels varied significantly as a function of age, those for the professional singers did not. Although trends occurred, no significant differences were found for the mean phonational range or habitual pitch levels when the professionals and nonsingers were compared.     

Investigations into vocal doses and parameters pertaining to primary school teachers in classrooms

Investigations into vocal doses and parameters were carried out on 40 primary school teachers (36 females and 4 males) in six schools in Italy, divided into two groups of three, A and B, on the basis of the type of building and the mid-frequency reverberation time in the classrooms, which was 1.13 and 0.79 s, respectively. A total of 73 working-day samples were collected (66 for females and 7 for males), from which 54 traditional lessons were analyzed separately. The average value over the working days of the mean sound pressure level of the voiced speech at 1 m from the teacher's mouth was 62.1 dB for the females and 57.7 dB for the males, while the voicing time percentage was 25.9 and 25.1 %, respectively. Even though the vocal doses and parameters did not differ for the two school groups, the differences in the subjective scores were significant, with enhanced scores in group B. A 0.72 dB increase in speech level per 1 dB increase in background noise level, L(A90), was found during traditional lessons, as well as an increase in the mean value of the fundamental frequency with an increase in L(A90), at a rate of 1.0 Hz/dB.     

Conditioning-induced protection from impulse noise in female and male chinchillas

Sound conditioning (pre-exposure to a moderate-level acoustic stimulus) can induce resistance to hearing loss from a subsequent traumatic exposure. Most sound conditioning experiments have utilized long-duration tones and noise at levels below 110 dB SPL as traumatic stimuli. It is important to know if sound conditioning can also provide protection from brief, high-level stimuli such as impulses produced by gunfire, and whether there are differences between females and males in the response of the ear to noise. In the present study, chinchillas were exposed to 95 dB SPL octave band noise centered at 0.5 kHz for 6 h/day for 5 days. After 5 days of recovery, they were exposed to simulated M16 rifle fire at a level of 150 dB peak SPL. Animals that were sound conditioned showed less hearing loss and smaller hair cell lesions than controls. Females showed significantly less hearing loss than males at low frequencies, but more hearing loss at 16 kHz. Cochleograms showed slightly less hair cell loss in females than in males. The results show that significant protection from impulse noise can be achieved with a 5-day conditioning regimen, and that there are consistent differences between female and male chinchillas in the response of the cochlea to impulse noise.     

Acoustic Characteristics of Vowels by Normal Malaysian Malay Young Adults

The acoustic characteristics of sustained vowel have been widely investigated across various languages and ethnic groups. These acoustic measures, including fundamental frequency (F₀), jitter (Jitt), relative average perturbation (RAP), five-point period perturbation quotient (PPQ5), shimmer (Shim), and 11-point amplitude perturbation quotient (APQ11) are not well established for Malaysian Malay young adults. This article studies the acoustic measures of Malaysian Malay adults using acoustical analysis. The study analyzed six sustained Malay vowels of 60 normal native Malaysian Malay adults with a mean of 21.19 years. The F₀ values of Malaysian Malay males and females were reported as 134.85 ± 18.54 and 238.27 ± 24.06 Hz, respectively. Malaysian Malay females had significantly higher F₀ than that of males for all the vowels. However, no significant differences were observed between the genders for the perturbation measures in all the vowels, except RAP in /e/. No significant F₀ differences between the vowels were observed. Significant differences between the vowels were reported for all perturbation measures in Malaysian Malay males. As for Malaysian Malay females, significant differences between the vowels were reported for Shim and APQ11. Multiethnic comparisons indicate that F₀ varies between Malaysian Malay and other ethnic groups. However, the perturbation measures cannot be directly compared, where the measures vary significantly across different speech analysis softwares.     

Consistency of acoustic and aerodynamic measures of voice production over 28 days under various testing conditions

The value of any measure of voice production is dependent on its repeatability over time. The purpose of the present study was to determine the consistency of selected acoustic and aerodynamic measures of voice production over 28 days, under various test/retest conditions. Three groups of healthy young adult females sustained three vowels at comfortable, high, and low pitch levels. Subjects in Group 1 chose their own intensity levels, but matched the fundamental frequencies produced at Test 1 during Test 2. Group 2 controlled intensity levels during both tests, but fundamental frequency was free to vary. Group 3 controlled both intensity and fundamental frequency. Measures of fundamental frequency, jitter, maximum phonation time, phonation volume, and flow rate were compared. Subjects who matched both fundamental frequency and intensity showed repeatable, consistent results for all measures during both tests. Controlling intensity but not fundamental frequency resulted in statistically significant differences in fundamental frequency at comfortable and high pitches, but there was minimal effect on other variables. Controlling fundamental frequency but not intensity led to the most inconsistency between tests, affecting both acoustic and aerodynamic measures. Results underscore the need to control the conditions under which measures are obtained.     

Effects of singing training on the speaking voice of voice majors

This longitudinal study gathered data with regard to the question: Does singing training have an effect on the speaking voice? Fourteen voice majors (12 females and two males; age range 17 to 20 years) were recorded once a semester for four consecutive semesters, while sustaining vowels and reading the "Rainbow Passage." Acoustic measures included speaking fundamental frequency (SFF) and sound pressure level (SLP). Perturbation measures included jitter, shimmer, and harmonic-to-noise ratio. Temporal measures included sentence, consonant, and diphthong durations. Results revealed that, as the number of semesters increased, the SFF increased while jitter and shimmer slightly decreased. Repeated measure analysis, however, indicated that none of the acoustic, temporal, or perturbation differences were statistically significant. These results confirm earlier cross-sectional studies that compared singers with nonsingers, in that singing training mostly affects the singing voice and rarely the speaking voice.     

Effects of vocal training on the acoustic parameters of the singing voice

Vocal training (VT) has, in part, been associated with the distinctions in the physiological, acoustic, and perceptual parameters found in singers' voices versus the voices of nonsingers. This study provides information on the changes in the singing voice as a function of VT over time. Fourteen college voice majors (12 females and 2 males; age range, 17–20 years) were recorded while singing, once a semester, for four consecutive semesters. Acoustic measures included fundamental frequency (F₀) and sound pressure level (SPL) of the 10% and 90% levels of the maximum phonational frequency range (MPFR), vibrato pulses per second, vibrato amplitude variation, and the presence of the singer's formant. Results indicated that VT had a significant effect on the MPFR. F₀ and SPL of the 90% level of the MPFR and the 90–10% range increased significantly as VT progressed. However, no vibrato or singers' formant differences were detected as a function of training. This longitudinal study not only validates previous cross-sectional research, ie, that VT has a significant effect on the singing voice, but also it demonstrates that these effects can be acoustically detected by the fourth semester of college vocal training.     

Acoustic Analyses of Trained Singers Perceptually Identified from Speaking Samples

This study investigated selected acoustic cues in the speaking voices of five professional singers; cues that may have enabled na?ve listeners to differentiate them from nonsingers and other trained singers who were not consistently identified from their speaking voices. Subjects were divided into three groups based on listeners' perceptual judgments. Group I, the identified singers, consisted of five professional singers, three males and two females, with an average identification score, from their speaking utterances, of 79%. Group II, the unidentified singers, consisted of 15 trained singers, seven males and eight females, who, as a group, were identified correctly from their speaking utterances only 52% of the time. Group III consisted of 20 nonsingers who were incorrectly identified from their speaking utterances as singers only 36% of the time, that is, they were correctly identified as nonsingers from their speech 64% of the time. Acoustic parameters chosen for measurement from vowel productions were: (1) percent jitter, (2) percent shimmer, and (3) noise-to-harmonic ratio. The second sentence of the "Rainbow Passage" was selected to compare several frequency and duration measures between the three groups. These were: (1) mean speaking fundamental frequency, (2) standard deviation of the fundamental frequency, (3) sentence duration, (4) word duration, and (5) consonant/vowel ratio. The data indicated that the acoustic parameters that most consistently distinguished the identified singers from the unidentified singers and the nonsingers were fundamental frequency variation and durational differences. The identified singers varied their speaking fundamental frequency significantly more than did both the unidentified singers and the nonsingers. The identified singers also had longer vocalic segments than did the others.     

Comparing behavioral and physiological measures of combination tones: Sex and race differences

Both distortion-product otoacoustic emissions (DPOAEs) and performance in an auditory-masking task involving combination tones were measured in the same frequency region in the same ears. In the behavioral task, a signal of 3.6?kHz (duration 300?ms, rise/fall time 20?ms) was masked by a 3.0-kHz tone (62?dB SPL, continuously presented). These two frequencies can produce a combination tone at 2.4?kHz. When a narrowband noise (2.0-2.8?kHz, 17?dB spectrum level) was added as a second masker, detection of the 3.6-kHz signal worsened by 6-9?dB (the Greenwood effect), revealing that listeners had been using the combination tone at 2.4?kHz as a cue for detection at 3.6?kHz. Several outcomes differed markedly by sex and racial background. The Greenwood effect was substantially larger in females than in males, but only for the White group. When the magnitude of the Greenwood effect was compared with the magnitude of the DPOAE measured in the 2.4?kHz region, the correlations typically were modest, but were high for Non-White males. For many subjects, then, most of the DPOAE measured in the ear canal apparently is not related to the combination-tone cue that is masked by the narrowband noise.     

Discrimination and identification of vowels by young, hearing-impaired adults

This study examined the effects of mild-to-moderate sensorineural hearing loss on vowel perception abilities of young, hearing-impaired (YHI) adults. Stimuli were presented at a low conversational level with a flat frequency response (approximately 60 dB SPL), and in two gain conditions: (a) high level gain with a flat frequency response (95 dB SPL), and (b) frequency-specific gain shaped according to each listener's hearing loss (designed to simulate the frequency response provided by a linear hearing aid to an input signal of 60 dB SPL). Listeners discriminated changes in the vowels /I e E inverted-v ae/ when F1 or F2 varied, and later categorized the vowels. YHI listeners performed better in the two gain conditions than in the conversational level condition. Performances in the two gain conditions were similar, suggesting that upward spread of masking was not seen at these signal levels for these tasks. Results were compared with those from a group of elderly, hearing-impaired (EHI) listeners, reported in Coughlin, Kewley-Port, and Humes [J. Acoust. Soc. Am. 104, 3597-3607 (1998)]. Comparisons revealed no significant differences between the EHI and YHI groups, suggesting that hearing impairment, not age, is the primary contributor to decreased vowel perception in these listeners.     

Discrimination of depth of sinusoidal amplitude modulation with and without roved carrier levels

Thresholds for the discrimination of the depth of sinusoidal amplitude modulation with a broadband noise carrier were measured for three listeners in a two-alternative, forced-choice task for modulation frequencies of 8, 32, and 128 Hz. Thresholds were measured with the spectrum level of the carrier fixed at 20 dB across all trials and, separately, with the carrier spectrum level roved randomly over a 20-dB range (10-30 dB) in each interval. Mean thresholds were equal or slightly lower (but not significantly so) for the fixed conditions relative to the roved conditions, and the differences between thresholds were too small to be explained by assuming that listeners compared instantaneous intensity at corresponding phases of the modulation cycle (for example, in the troughs). Rather, it appears that listeners discriminated modulation depth by extracting an estimate of the modulation depth within each interval that was independent of the overall level. Consequently, models of envelope extraction must include normalization of the envelope fluctuations to the envelope dc.     

Gender differences in children's intonational patterns

This study investigated differences among intonational variables in prepubescent girls' and boys' voices in conversational speech (American-English). Subjects were middle class boys and girls at each of four age levels: 3–4, 5–6, 7–8, and 9–10 years. Samples of conversational speech were recorded and acoustically analyzed for minimum and maximum FO, mean FO, and SD of FO (FOSD), as well as number and direction of FO changes (“shifts”) per utterance. Findings indicated that the mean FO of the males decreased at around age 7–8 years. Additionally, maximum FO, range, and percentage of rising and falling shifts all showed decreases for the males starting at ages 7–8 not paralleled by decreases for the females. Both physiological and sociocultural factors appear to account for the changes that mark the development of intonational patterns in prepubertal girls and boys.     

New hearing threshold measurements for pure tones under free-field listening conditions.

Hearing thresholds for pure tones were measured under free-field listening conditions in the frequency range of 40 Hz-15 kHz. Results are consistent with the standard threshold specified in ISO 226 for frequencies up to 250 Hz, but a few dB below the ISO curve at higher frequencies. Thresholds are distributed normally on a logarithmic level scale with a standard deviation of approximately 5 dB. No significant differences between thresholds of male and female subjects were observed.     

Effects of nosocusis, and industrial and gun noise on hearing of U.S. adults.

Hearing losses estimated for exposure to industrial and gun noise and for "typical" nosocusis are applied to the distributions of the hearing levels of adult males and females of the general population of an industrialized society unscreened for exposure to noise or ear disease. Noise exposure and demographic data applicable to the United States, and procedures for predicting noise-induced permanent threshold shift (NIPTS) and nosocusis, were used to account for some 8.7 dB of the 13.4 dB average difference between the hearing levels at high frequencies for otologically and noise screened versus unscreened male ears; (this average difference is for the average of the hearing levels at 3000, 4000, and 6000 Hz, average for the 10th, 50th, and 90th percentiles, and ages 20-65 years). According to the present calculations, this difference is due, in order of importance, to (1) nosocusis, (2) exposure to gun noise, and (3) exposure of workers to industrial noise. For these same frequencies and overall average, adjustments for nosocusis accounts for 2 dB of the 5.9-dB difference between the hearing levels of screened and unscreened female ears. For the average at 500, 1000, and 2000 Hz, the overall differences between the screened and unscreened populations is but 3.4 dB for males and 2.9 dB for females. The adjustment procedures reduced these differences to -0.5 and 0.9 dB, respectively.     

Intensity discrimination with cochlear implants

Intensity difference limens were measured for various frequencies and intensities of sinusoidal and pulsatile electrical stimulation in monkeys with electrodes implanted in the scala tympani, scala vestibuli, modiolus, or middle ear. Difference limens decreased, as a function of initial stimulus intensity, from values of 1.5-3 dB near threshold to as low as 0.5 dB near the upper limit of the dynamic range. If sensation level was held constant, difference limens decreased as a function of frequency up to about 500 Hz, and then remained constant. They were similar across a variety of electrode placements and separations if differences in threshold and dynamic range were taken into account. However, difference limens measured in severely damaged ears were slightly smaller than those in moderately damaged ears. The near miss to Weber's law, characteristic of acoustic difference limens, was not seen with electrical stimuli. Differences limens for electrical stimuli were roughly one-half those for acoustic stimuli; thus, part of the deficit in dynamic range for electrical stimulation compared with acoustic stimulation is countered by the smaller intensity differences limens for electrical stimuli.     

The sound level of the singer's formant in professional singing

The relative sound level of the "singer's formant," measured in a 1/3-oct band with a center frequency of 2.5 kHz for males and of 3.16 kHz for females, has been investigated for 14 professional singers, nine different modes of singing, nine different vowels, variations in overall sound-pressure level, and fundamental frequencies ranging from 98 up to 880 Hz. Variation in the sound level of the singer's formant due to differences among male singers was small (4 dB), the factors vowels (16 dB) and fundamental frequency (9-14 dB) had an intermediate effect, while the largest variation was found for differences among female singers (24 dB), between modes of singing (vocal effort) (23 dB), and in overall sound-pressure level (more than 30 dB). In spite of this great potential variability, for each mode of singing the sound level of the singer's formant was remarkably constant up to F0 = 392 Hz, due to adaptation of vocal effort. This may be explained as the result of the perceptual demand of a constant voice quality. The definition of the singer's formant is discussed.     

Factors affecting the loudness of modulated sounds.

Loudness matches were obtained between unmodulated carriers and carriers that were amplitude modulated either periodically (rates between 2 and 32 Hz, modulation sinusoidal either on a linear amplitude scale or on a dB scale; the latter is called dB modulation) or with the envelope of the speech of a single talker. The carrier was a 4-kHz sinusoid, white noise, or speech-shaped noise. Both normally hearing subjects and subjects with cochlear hearing loss were tested. Results were expressed as the root-mean-square (rms) level of the modulated carrier minus the level of the unmodulated carrier at the point of equal loudness. If this difference is positive, this indicates that the modulated carrier has a higher rms level at the point of equal loudness. For normally hearing subjects, the results show: (1) For a 4000-Hz sinusoidal carrier, the difference was slightly positive (averaging about 0.7 dB). There was no significant effect of modulation rate or level over the range 20-80 dB SL. (2) For a speech-shaped noise or white noise carrier, the difference was close to zero, although for large modulation depths it tended to be negative. There was no clear effect of level (over the range 35-75 dB SPL) or modulation rate. For the hearing-impaired subjects, the differences were small, but tended to be slightly negative for both the 4000-Hz carrier and the noise carriers, when the modulation rate was above 2 Hz. Again, there was no clear effect of overall level. However, for dB modulation, the differences became more negative with increasing modulation depth. For modulation rates in the range 4-32 Hz, the results could be fitted reasonably well using the assumption that the loudness of modulated sounds is based on the rms value of the time-varying intensity of the response of the basilar membrane (taking into account the compression that occurs in the normal cochlea). The implications of the results for the fitting of multi-band compression hearing aids and for the design of loudness meters are discussed.     

Comparison of the Produced and Perceived Voice Range Profiles in Untrained and Trained Classical Singers

Frequency and intensity ranges (in true decibel sound pressure level, 20 microPa at 1 m) of voice production in trained and untrained vocalists were compared with the perceived dynamic range (phons) and units of loudness (sones) of the ear. Results were reported in terms of standard voice range profiles (VRPs), perceived VRPs (as predicted by accepted measures of auditory sensitivities), and a new metric labeled as an overall perceptual level construct. Trained classical singers made use of the most sensitive part of the hearing range (around 3-4 kHz) through the use of the singer's formant. When mapped onto the contours of equal loudness (depicting nonuniform spectral and dynamic sensitivities of the auditory system), the formant is perceived at an even higher sound level, as measured in phons, than a flat or A-weighted spectrum would indicate. The contributions of effects like the singer's formant and the sensitivities of the auditory system helped the trained singers produce 20% to 40% more units of loudness, as measured in sones, than the untrained singers. Trained male vocalists had a maximum overall perceptual level construct that was 40% higher than the untrained male vocalists. Although the A-weighted spectrum (commonly used in VRP measurement) is a reasonable first-order approximation of auditory sensitivities, it misrepresents the most salient part of the sensitivities (where the singer's formant is found) by nearly 10 dB.     

Acoustic and linguistic factors in the perception of bandpass-filtered speech

Speech can remain intelligible for listeners with normal hearing when processed by narrow bandpass filters that transmit only a small fraction of the audible spectrum. Two experiments investigated the basis for the high intelligibility of narrowband speech. Experiment 1 confirmed reports that everyday English sentences can be recognized accurately (82%-98% words correct) when filtered at center frequencies of 1500, 2100, and 3000 Hz. However, narrowband low predictability (LP) sentences were less accurately recognized than high predictability (HP) sentences (20% lower scores), and excised narrowband words were even less intelligible than LP sentences (a further 23% drop). While experiment 1 revealed similar levels of performance for narrowband and broadband sentences at conversational speech levels, experiment 2 showed that speech reception thresholds were substantially (>30 dB) poorer for narrowband sentences. One explanation for this increased disparity between narrowband and broadband speech at threshold (compared to conversational speech levels) is that spectral components in the sloping transition bands of the filters provide important cues for the recognition of narrowband speech, but these components become inaudible as the signal level is reduced. Experiment 2 also showed that performance was degraded by the introduction of a speech masker (a single competing talker). The elevation in threshold was similar for narrowband and broadband speech (11 dB, on average), but because the narrowband sentences required considerably higher sound levels to reach their thresholds in quiet compared to broadband sentences, their target-to-masker ratios were very different (+23 dB for narrowband sentences and -12 dB for broadband sentences). As in experiment 1, performance was better for HP than LP sentences. The LP-HP difference was larger for narrowband than broadband sentences, suggesting that context provides greater benefits when speech is distorted by narrow bandpass filtering.     

Listeners' identification and discrimination of digitally manipulated sounds as prolongations

The present study had two main purposes. One was to examine if listeners perceive gradually increasing durations of a voiceless fricative categorically ("fluent" versus "stuttered") or continuously (gradient perception from fluent to stuttered). The second purpose was to investigate whether there are gender differences in how listeners perceive various duration of sounds as "prolongations." Forty-four listeners were instructed to rate the duration of the // in the word "shape" produced by a normally fluent speaker. The target word was embedded in the middle of an experimental phrase and the initial // sound was digitally manipulated to create a range of fluent to stuttered sounds. This was accomplished by creating 20 ms stepwise increments for sounds ranging from 120 to 500 ms in duration. Listeners were instructed to give a rating of 1 for a fluent word and a rating of 100 for a stuttered word. The results showed listeners perceived the range of sounds continuously. Also, there was a significant gender difference in that males rated fluent sounds higher than females but female listeners rated stuttered sounds higher than males. The implications of these results are discussed.