Comparison of acoustic and perceptual measures of voice in male-to-female transsexuals perceived as female versus those perceived as male

The present study explored significant differences between male-to-female transgendered speakers perceived as male and those perceived as female in terms of speaking fundamental frequency (SFF) and its variability, vowel formants for /a/ and /i/, and intonation measures. Fifteen individuals who identified themselves as male-to-female transsexuals served as speaker subjects, in addition to 6 biological female control subjects and 3 biological male control subjects. Each subject was recorded reading the Rainbow Passage and producing the isolated vowels /a/ and /i/. Twenty undergraduate psychology students served as listeners. Results indicated that subjects perceived as female had a higher mean SFF and higher upper limit of SFF than subjects perceived as male. A significant correlation between upper limit of SFF and ratings of femininity was achieved.     

Effects on the glottal voice source of vocal loudness variation in untrained female and male voices

Subglottal pressure is one of the main voice control factors, controlling vocal loudness. In this investigation the effects of subglottal pressure variation on the voice source in untrained female and male voices phonating at a low, a middle, and a high fundamental frequency are analyzed. The subjects produced a series of /pae/ syllables at varied degrees of vocal loudness, attempting to keep pitch constant. Subglottal pressure was estimated from the oral pressure during the /p/ occlusion. Ten subglottal pressure values, approximately equidistantly spaced within the pressure range used, were identified, and the voice source of the vowels following these pressure values was analyzed by inverse filtering the airflow signal as captured by a Rothenberg mask. The maximum flow declination rate (MFDR) was found to increase linearly with subglottal pressure, but a given subglottal pressure produced lower values for female than for male voices. The closed quotient increased quickly with subglottal pressure at low pressures and slowly at high pressures, such that the relationship can be approximated by a power function. For a given subglottal pressure value, female voices reached lower values of closed quotient than male voices.     

Formant Frequencies of Malay Vowels Produced by Malay Children Aged Between 7 and 12 Years

The formant frequencies of Malaysian Malay children have not been well studied. This article investigates the first four formant frequencies of sustained vowels in 360 Malay children aged between 7 and 12 years using acoustical analysis. Generally, Malay female children had higher formant frequencies than those of their male counterparts. However, no significant differences in all four formant frequencies were observed between the Malay male and female children in most of the vowels and age groups. Significant differences in all formant frequencies were found across the Malay vowels in both Malay male and female children for all age groups except for F4 in female children aged 12 years. Generally, the Malaysian Malay children showed a nonsystematic decrement in formant frequencies with age. Low levels of significant differences in formant frequencies were observed across the age groups in most of the vowels for F1, F3, and F4 in Malay male children and F1 and F4 in Malay female children.     

Reliability in Perceptual Analysis of Voice Quality

This study focuses on speaking voice quality in male teachers (n = 35) and male actors (n = 36), who represent untrained and trained voice users, because we wanted to investigate normal and supranormal voices. In this study, both substantial and methodologic aspects were considered. It includes a method for perceptual voice evaluation, and a basic issue was rater reliability. A listening group of 10 listeners, 7 experienced speech-language therapists, and 3 speech-language therapist students evaluated the voices by 15 vocal characteristics using VA scales. Two sets of voice signals were investigated: text reading (2 loudness levels) and sustained vowel (3 levels). The results indicated a high interrater reliability for most perceptual characteristics. Connected speech was evaluated more reliably, especially at the normal level, but both types of voice signals were evaluated reliably, although the reliability for connected speech was somewhat higher than for vowels. Experienced listeners tended to be more consistent in their ratings than did the student raters. Some vocal characteristics achieved acceptable reliability even with a smaller panel of listeners. The perceptual characteristics grouped in 4 factors reflected perceptual dimensions.     

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.     

Feature Maps of the Acoustic Spectrum of the Voice

The change in the spectrum of sustained /a/ vowels was mapped over the voice range from low to high fundamental frequency and low to high sound pressure level (SPL), in the form of the so-called voice range profile (VRP). In each interval of one semitone and one decibel, narrowband spectra were averaged both within and across subjects. The subjects were groups of 7 male and 12 female singing students, as well as a group of 16 untrained female voices. For each individual and also for each group, pairs of VRP recordings were made, with stringent separation of the modal/chest and falsetto/head registers. Maps are presented of eight scalar metrics, each of which was chosen to quantify a particular feature of the voice spectrum, over fundamental frequency and SPL. Metrics 1 and 2 chart the role of the fundamental in relation to the rest of the spectrum. Metrics 3 and 4 are used to explore the role of resonances in relation to SPL. Metrics 5 and 6 address the distribution of high frequency energy, while metrics 7 and 8 seek to describe the distribution of energy at the low end of the voice spectrum.Several examples are observed of phenomena that are difficult to predict from linear source-filter theory, and of the voice source being less uniform over the voice range than is conventionally assumed. These include a high-frequency band-limiting at high SPL and an unexpected persistence of the second harmonic at low SPL. The two voice registers give rise to clearly different maps. Only a few effects of training were observed, in the low frequency end below 2 kHz. The results are of potential interest in voice analysis, voice synthesis and for new insights into the voice production mechanism.     

Aerodynamic Analysis of Male-to-Female Transgender Voice

The attainment of a feminine-sounding voice is a highly desirable goal among male-to-female transgender (MFT) persons, but this goal may be difficult for many to accomplish. The characteristics associated with a feminine vocal quality include increases in fundamental frequency and in vocal breathiness. In this study, we used inverse-filtering of the airflow signal to indirectly assess vocal fold function in 13 MFT persons. Each participant was asked to sustain the vowel /a/ first in her biological male voice and then again in her female voice. In addition, these vowel productions were compared with vowels produced by age-matched biologic women and men. The results of the study revealed a significant increase in maximum flow declination rate during female voice production. Perceptual ratings of a feminine voice were associated with a fundamental frequency (F0) of 180 Hz or greater, although F0 did not differ significantly between male and female voice production. These results are discussed relative to the mechanisms that obtained a feminine-sounding voice.     

Perceptual confusions of high-pitched sung vowels

Questions exist as to the intelligibility of vowels sung at extremely high fundamental frequencies and, especially, when the fundamental frequency (F0) produced is above the region where the first vowel formant (F1) would normally occur. Can such vowels be correctly identified and, if so, does context provide the necessary information or are acoustical elements also operative? To this end, 18 professional singers (5 males and 13 females) were recorded when singing 3 isolated vowels at high and low pitches at both loud and soft levels. Aural-perceptual studies employing four types of auditors were carried out to determine the identity of these vowels, and the nature of the confusions with other vowels. Subsequent acoustical analysis focused on the actual fundamental frequencies sung plus those defining the first 2 vowel formants. It was found that F0 change had a profound effect on vowel perception; one of the more important observations was that the target tended to shift toward vowels with an F1 just above the sung frequency.     

A Comparison of Two Methods of Formant Frequency Estimation for High-Pitched Voices

This study sought to compare formant frequencies estimated from natural phonation to those estimated using two methods of artificial laryngeal stimulation: (1) stimulation of the vocal tract using an artificial larynx placed on the neck and (2) stimulation of the vocal tract using an artificial larynx with an attached tube placed in the oral cavity. Twenty males between the ages of 18 and 45 performed the following three tasks on the vowels /a/ and /i/: (1) 4 seconds of sustained vowel, (2) 2 seconds of sustained vowel followed by 2 seconds of artificial phonation via a neck placement, and (3) 4 seconds of sustained vowel, the last two of which were accompanied by artificial phonation via an oral placement. Frequencies for formants 1-4 were measured for each task at second 1 and second 3 using linear predictive coding. These measures were compared across second 1 and second 3, as well as across all three tasks. Neither of the methods of artificial laryngeal stimulation tested in this study yielded formant frequency estimates that consistently agreed with those obtained from natural phonation for both vowels and all formants. However, when estimating mean formant frequency data for samples of large N, each of the methods agreed with mean estimations obtained from natural phonation for specific vowels and formants. The greatest agreement was found for a neck placement of the artificial larynx on the vowel /a/.     

Throaty Voice Quality: Subglottal Pressure, Voice Source, and Formant Characteristics

"Throaty" voice quality has been regarded by voice pedagogues as undesired and even harmful. This study attempts to identify acoustic and physiological correlates of this quality. One male and one female subject read a text habitually and with a throaty voice quality. Oral pressure during p-occlusion was measured as an estimate of subglottal pressure. Long-term average spectrum analysis described the average spectrum characteristics. Sixteen syllables, perceptually evaluated with regard to throaty quality by five experts, were selected for analysis. Formant frequencies and voice source characteristics were measured by means of inverse filtering, and the vocal tract shape of the throaty and normal versions of the vowels [a,u,i,ae] of the male subject were recorded by magnetic resonance imaging. From this material, area functions were derived and their resonance frequencies were determined. The throaty versions of these four vowels all showed a pharynx that was narrower than in the habitually produced versions. To test the relevance of formant frequencies to perceived throaty quality, experts rated degree of throatiness in synthetic vowel samples, in which the measured formant frequency values of the subject were used. The main acoustic correlates of throatiness seemed to be an increase of F1, a decrease of F4, and in front vowels a decrease of F2, which presumably results from a narrowing of the pharynx. In the male subject, voice source parameters suggested a more hyperfunctional voice in throaty samples.     

Gender presentation: Perceptual and acoustical analysesof voice

This study investigated the perceptual and acoustical characteristicsof vocal presentation in both the masculine and the feminine modes by the same group of male subjects. Listeners (N = 88) evaluated 22 voice samples by using 18 semantic differential scales and 57 adjectives. The 22 voice samples were provided by I I biologically male speakers, who described themselves as heterosexual crossdressers. Each speaker read a standard passage under controlled conditions. In one reading, they demonstrated their typical masculine voice and in the other they spoke in their feminine voice. Acoustical analyses included mean fundamental frequency, frequency range, overall passage duration, and duration of a sample of stressed vowels. Results indicated that listeners heard significant differences between masculine and feminine presentations across the I I speakers and the 18 semantic differential scales. Masculine-feminine and high-low pitch were the most salient scales in the perceptual judgments. Acoustical analyses indicated wide variation according to speaker and condition. Clinical applications are provided.     

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.     

Multimodal Standardization of Voice Among Four Multicultural Populations: Fundamental Frequency and Spectral Characteristics

A stratified random sample of 20 males and 20 females matched for physiological factors and cultural-linguistic markers were examined to determine differences in fundamental frequency and spectral characteristics during prolongation of three vowels: [a], [i], and [u]. The ethnic-gender breakdown included four sets of five male and five female subjects comprised of Caucasian and African-American speakers of standard American English, native Hindi Indian speakers, and native Mandarin Chinese speakers. Acoustic measures were analyzed using the Multidimensional Voice Program (Kay Elemetrics, Lincoln Park, NJ) (Model 4305) from which fundamental frequency and associated acoustic spectra were extracted from a 200-ms sample of each vowel token. Statistically significant group differences for the main effects of culture, race, and gender were found. The acoustic differences found are attributed to biomechanical, physiological, cultural, and linguistic factors.     

An acoustic description of the vowels of Northern and Southern Standard Dutch

A database is presented of measurements of the fundamental frequency, the frequencies of the first three formants, and the duration of the 15 vowels of Standard Dutch as spoken in the Netherlands (Northern Standard Dutch) and in Belgium (Southern Standard Dutch). The speech material consisted of read monosyllabic utterances in a neutral consonantal context (i.e., /sVs/). Recordings were made for 20 female talkers and 20 male talkers, who were stratified for the factors age, gender, and region. Of the 40 talkers, 20 spoke Northern Standard Dutch and 20 spoke Southern Standard Dutch. The results indicated that the nine monophthongal Dutch vowels /a [see symbol in text] epsilon i I [see symbol in text] u y Y/ can be separated fairly well given their steady-state characteristics, while the long mid vowels /e o ?/ and three diphthongal vowels /epsilon I [see symbol in text]u oey/ also require information about their dynamic characteristics. The analysis of the formant values indicated that Northern Standard Dutch and Southern Standard Dutch differ little in the formant frequencies at steady-state for the nine monophthongal vowels. Larger differences between these two language varieties were found for the dynamic specifications of the three long mid vowels, and, to a lesser extent, of the three diphthongal vowels.     

Acoustic analysis and perception of vowels in children's and teenagers' stuttered speech.

The syllable repetitions of 24 child and eight teenage stutterers were investigated to assess whether the vowels neutralize and, if so, what causes this. In both groups of speakers, the vowel in CV syllable repetitions and the following fluent vowel were excised from conversational speech samples. Acoustic analyses showed the formant frequencies of vowels in syllable repetitions to be appropriate for the intended vowel and the duration of the dysfluent vowels to be shorter than those of the fluent vowels for both groups of speakers. The intensity of the fluent vowels was greater than that of the dysfluent vowels for the teenagers but not the children: For both age groups, excitation waveforms obtained by inverse filtering showed that the excitation spectra associated with dysfluent vowels fell off more rapidly with frequency than did those associated with the fluent vowels. The fundamental frequency of the children's dysfluent speech was higher than their fluent speech while there was no difference in the teenager's speech. The relationship between the intensities of the glottal volume velocities was the same as that of the speech waveforms. Perceptual tests were also conducted to assess whether duration and the differences found in the source excitation would make children's vowels sound neutral. The experiments show that in children neither vowel duration nor fundamental frequency differences cause the vowels to be perceived as neutral. The results suggest that the low intensity and characteristics of the source of excitation which cause vowels to sound neutral may only occur in late childhood. Furthermore, monitoring stuttered speech for the emergence of neutral vowels may be a way of indexing the progress of the disorder.     

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.     

The relationship of vocal tract shape to three voice qualities

Three-dimensional vocal tract shapes and consequent area functions representing the vowels [i, ae, a, u] have been obtained from one male and one female speaker using magnetic resonance imaging (MRI). The two speakers were trained vocal performers and both were adept at manipulation of vocal tract shape to alter voice quality. Each vowel was performed three times, each with one of the three voice qualities: normal, yawny, and twangy. The purpose of the study was to determine some ways in which the vocal tract shape can be manipulated to alter voice quality while retaining a desired phonetic quality. To summarize any overall tract shaping tendencies mean area functions were subsequently computed across the four vowels produced within each specific voice quality. Relative to normal speech, both the vowel area functions and mean area functions showed, in general, that the oral cavity is widened and tract length increased for the yawny productions. The twangy vowels were characterized by shortened tract length, widened lip opening, and a slightly constricted oral cavity. The resulting acoustic characteristics of these articulatory alterations consisted of the first two formants (F1 and F2) being close together for all yawny vowels and far apart for all the twangy vowels.     

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.