Singing Power Ratio Research Articles

Bhramari Pranayama - A Unique Voice Culturing Technique

A good voice is the basic need of humans. For professional voice users, voice governs their livelihood and social attraction. A good singing voice is attained by the regular vocal exercises and vocal training. Singing involves the skills like respiration, phonation, resonance and articulation. Bhramari Pranayama (BP) involves both humming and respiration. Humming is the resultant of the activity vocal structures which may have effect on the quality of the voice. Aim: To evaluate the effect of Bhramari Pranayama (BP) on voice quality
 Settings and Design: The study is an open clinical trial involving 30 healthy prospective singers fulfilling the inclusion and exclusion criteria, consenting for the study, who were enrolled through a survey in music schools in the region of Belagavi, Karnataka. Methods and Material: The voice of the 30 healthy prospective singers was recorded using PRAAT software with standard vocal tasks on day 0 of the study. Participants practiced 21 cycles of Bhramari Pranayama in the morning for 30 days. On Day 30, after the practice the voice was re-recorded with same vocal tasks and standard operative procedures being maintained. The recorded voice samples were saved and were subjected for voice analysis using softwares PRAAT, Vaghmi, CSL at AIISH, Mysuru. Statistical analysis used: Statistical analysis was done using SPSS 21 and Paired ‘t’ test was applied to derive the results. Statistical Significance was set up at p<0.05. Results: Bhramari pranayama showed highly significant results in the root mean square values of the Singing power ratio - SPR (p<0.01) and singing power difference (p<0.01). Significant results in the lowest value of the singing amplitude (p<0.05), singing amplitude range (p<0.01) and mean formant frequency of second formant of vowel /u/(p<0.05). Conclusion: Bhramari Pranayama improved the resonance characteristics of the voice and there by improved the quality of singing voice in prospective singers.

The effect of acoustic environments on singers’ vocal behaviors and mental effort

Singers perform in various acoustic environments; however, how the environments affect their mental effort is poorly understood. This study virtually simulated acoustic environments to examine the effect of reverberation time on singers’ vocal behaviors and mental effort. Participants were five vocally healthy singers who completed a minimum of undergraduate-level training. For the virtual environments, the voice signal was digitally processed by adding reverberation using a real-time effect processor of the digital mixer. The processed sound was played back to the participant using open headphones. The average T30 was 1.13 s in Low T30 condition, 1.39 s in Medium T30 condition, and 1.90 s in High T30 condition. Participants sang the American national anthem and rated their perceived level of overall effort, mental effort, physical effort, frustration, and performance using a modified NASA-TLX scale for each acoustic condition. Pupillometry was also used to measure the mental effort during each task. Their voice recordings were acoustically analyzed for intensity, singing-power ratio, alpha ratio, pitch accuracy, and vibrato rate and extent. The presentation will discuss: (1) individual differences in the participants’ response to the reverberation time and (2) the degree of agreement between the subjective rating and physical measurement of mental effort.

A Longitudinal Ageing Analysis of Vocal Parameters of Singing Voice of Female Playback Singer

Age-related changes to the vocal structure affect the singing ability of the singer. We present a longitudinal study of vocal ageing of a female professional playback singer having more than six decades of singing span (covering singer age from 19 to 80 years). The ageing analysis is performed on six vocal parameters like – fundamental frequency (F0), vibrato, formants and spectral features like spectral roll-off and centroid. Statistical variations in these vocal parameters over the entire singing span of the singer are discussed in the paper. Significant effects noted with the ageing voice were - decrease in F0, decreased vocal range, reduction in vibrato rate, increase in vibrato extent, decrease in F2 & F4 formants and rapid change in the spectral features. This investigation also studied the effect of ageing on singing voice quality through the measurement of singing power ratio (SPR). Increase in SPR measures was observed with ageing voice. The study of impact of vocal ageing with longitudinal data on singer identification (SID) is scare. The SID experimentation performed with 350 cappella songs covering entire singing span of the singer, showed a clear impact that change in acoustical parameters with ageing affected the performance of singer identification systems.

Singing Voice Quality: The Effects of Maxillary Dental Arch and Singing Style

In classical singing techniques, it is common to manipulate the vocal tract to channel airflow to increase voice quality and volume. Technique varies according to the style of the music, the voice type, and range of a given singer. Although these practices are intentional, fixed physiological aspects of a singer's vocal instrument also play an extremely impactful role in determining voice quality. In the present study, the relationship between the dimensions of the maxillary dental arch and voice quality were examined in professional singers. The dimensions of the palate were measured from the maxillary dental casts of 14 female singers. Audio recordings were made for the same participants while singing a sustained /a/ singing vowel, a glissando, the song "Are You Sleeping", and a selected song from their personal repertoire. The dimensions of the palate were measured from maxillary dental casts. From the recordings, two parameters were calculated: (1) the Singing Power Ratio (SPR) and (2) A2 A1 ratio. Higher SPR values indicate a stronger ring in the voice, typical of operatic singing style, while higher A2 A1 ratio values are associated with the belting singing style. Singers with larger frontal palate depth, smaller posterior palate depth, larger frontal palate width, and smaller posterior palate width seem to be more suitable for an operatic singing style. Singers who had larger overall depth and width of the palate measurements produced an increased second harmonic, typical of the belting style. When considering a singer's ability to produce vocalizations successfully, physiological structure is an increasingly important factor. The present study discovered that palate depth and width are associated with statistically significant differences in SPR and A2/A1 parameters. These parameters correlate with two styles of singing, operatic, and belting respectively.

The Effect of Head Flexion/Extension on Acoustic Measures of Singing Voice Quality

A study was undertaken to identify the effect of head flexion/extension on singing voice quality. The amplitude of the fundamental frequency (F0) and the singing power ratio (SPR), an indirect measure of Singer's Formant activity, were measured. F0 and SPR scores at four experimental head positions were compared with the subjects' scores at their habitual positions. Three vowels and three pitch levels were tested. F0 amplitudes and low-frequency partials in general were greater with neck extension, while SPR increased with neck flexion. No effect of pitch or vowel was found. Gains in SPR appear to be the result of damping low-frequency partials rather than amplifying those in the Singer's Formant region. Raising the amplitude of F0 is an important resonance tool for female voices in the high range, and may be of benefit to other voice types in resonance, loudness, and laryngeal function.

La resonancia del cante flamenco: un estudio acústico y comparativo con el canto clásico

In a singeŕs vocal assessment it is not sufficient to diagnose the existence of resonance without also specifying its quality. A resonated voice has a broad harmonic content and can be achieved in many ways. ObjectiveTo analyze and validate Alfredo Krausśs hypothesis on the use of paranasal sinuses by flamenco singers, in order to naturalize voice sound, also called “/i/ technique”, equalizing all sounds based on this vowel. We translated this hypothesis into acoustic parameters using Singing Power Ratio (SPR) as a resonance measure of different vowels. MethodParticipants were divided into: a)Flamenco Experimental Group (FEG), 23 flamenco singers recruited from the Cristina Heeren Foundation in Seville, Garrotín Flamenco School and Reina Sofía Flamenco School in Granada, and b)Classical Control Group (CCG), 21 classical singers from the Cristobal de Morales conservatory in Seville and Victoria Eugenia conservatory in Granada. All the participants had over 2 years of experience. The SPR was calculated in sustained phonation tasks using Fast Fourier Transformation (FFT) algorithm for the vowels /a/, /i/, /u/. A comparative assessment between the groups was made using ANOVA. ResultsSignificant differences were found only in /i/, where the FEG obtained higher resonance values than CCG (up to 7bB difference). ConclusionsSound support in the vowel /i/ indicates how flamenco singers place vocal tract to amplify voice sound during singing, as Krauss suggests. Therefore, flamenco singers’ resonance technique differs from the classical.

Acoustic Analysis of Voice in Singers: A Systematic Review.

Singers are vocal athletes having specific demands from their voice and require special consideration during voice evaluation. Presently, there is a lack of standards for acoustic evaluation in them. The aim of the present study was to systematically review the available literature on the acoustic analysis of voice in singers. A systematic review of studies on acoustic analysis of voice in singers (PubMed/MEDLINE, CINAHL, Scopus, ProQuest, Cochrane, Ovid, Science Direct, and Shodhganga) was carried out. Key words based on PIO (population-investigation-outcome) were used to develop search strings. Titles and abstracts were screened independently, and appropriate studies were read in full for data extraction. Of the 895 studies, 26 studies met the inclusion criteria. Great variability was noted in the instruments and task used. Different acoustic measures were employed, such as fundamental frequency, perturbation, cepstral, spectral, dysphonia severity index, singing power ratio, and so forth. Overall, a great heterogeneity was noted regarding population, tasks, instruments, and parameters. There is a lack of standardized criteria for the evaluation of singing voice. In order to implement acoustic analysis as a part of comprehensive voice evaluation exclusively for singers, there is a certain need for methodical sound studies.

Aerobic Exercise as a Warm-up for Singing: Acoustic Impacts

In a previous work, it was found that a 30-minute aerobic workout significantly increased singers' sound pressure level and airflow during voicing, suggesting a shift to flow phonation. This companion study was designed to assess the impact of the same workout on pitch accuracy, vibrato rate, extent and regularity, and the singing power ratio. This study is a cohort experimental study. Twenty-two students in an academic vocal performance program participated. They performed an aerobic workout for 30 minutes. Before and after the workout, they sang the first seven notes of the "Star-Spangled Banner" on /pa/, producing seven /pa/s on the last note. The students then sang an ascending and descending scale to the ninth on "ah." The following measures were obtained from the "Star-Spangled Banner": pitch accuracy calculated on the seventh note ("by"); and vibrato rate, regularity, and extent, calculated on the most sustained sixth note ("see"). For the scale, the following measures were calculated from each note: pitch accuracy; vibrato rate, regularity, and extent; and the singing power ratio. There were no significant differences from pre- to postworkout across any measures. It appears that an aerobic workout positively impacts the respiratory driving force for voice production but does little for phonation. Critical for performance is the fine tuning and balancing across the respiratory, laryngeal, and resonance systems. It appears that this can only be achieved with vocalization exercises, facilitating coordination within and across the physiological systems involved in the complex art of bel canto.

Objective Identification of Prepubertal Female Singers and Non-singers by Singing Power Ratio Using Matlab

The field of music is increasingly gaining scope and attracting researchers from varied fields in terms of improvising the art of voice modulation in singing. There has been a lot of competition, and young budding singers are emerging with more talent. This study is aimed to develop software to differentiate a prepubertal voice as that of a singer or a non-singer using an objective tool-singing power ratio (SPR)-as an objective measure to quantify the resonant voice quality. Recordings of singing and phonation were obtained from 30 singers and 30 non-singer girls (8-10 years). Three professional singers perceptually evaluated all samples using a rating scale and categorized them as singers or non-singers. Using Matlab, a program was developed to automatically calculate the SPR of a particular sample and classify it into either of two groups based on the normative values of SPR developed manually. Positive correlation for SPR of phonation or singing was found between perceptual and manual ratings, and objective values of SPR. Software could automatically give the SPR values for samples that are fed and could further differentiate them as singer or non-singer. Researchers need not depend on professional singers or musicians for the judgment of voice for research purposes. This software uses an objective tool, which serves as an instrument to judge singing talent using singing and phonation samples of children. Also, it can be used as a first line of judgment in any singing audition process, which could ease the work of professionals.

Voice Quality After a Semi-Occluded Vocal Tract Exercise With a Ventilation Mask in Contemporary Commercial Singers: Acoustic Analysis and Self-Assessments

The current study aimed at investigating the immediate effects of a semi-occluded vocal tract exercise with a ventilation mask in a group of contemporary commercial singers. A randomized controlled study was carried out. Thirty professional or semi-professional singers with no voice complaints were randomly divided into two groups on recruitment: an experimental group and a control group. The same warm-up exercise was performed by the experimental group with an occluded ventilation mask placed over the nose and the mouth and by the control group without the ventilation mask. Voice was recorded before and after the exercise. Acoustic and self-assessment analysis were accomplished. The acoustic parameters of the voice samples recorded before and after training were compared, as well as the parameters' variations between the experimental and the control group. Self-assessment results of the experimental and the control group were compared too. Significant changes after the warm-up exercise included jitter, shimmer, and singing power ratio (SPR) in the experimental group. No significant changes were recorded in the control group. Significant differences between the experimental and the control group were found for ΔShimmer and ΔSPR. Self-assessment analysis confirmed a significantly higher phonatory comfort and voice quality perception for the experimental group. The results of the present study support the immediate advantageous effects on singing voice of a semi-occluded vocal tract exercise with a ventilation mask in terms of acoustic quality, phonatory comfort, and voice quality perception in contemporary commercial singers. Long-term effects still remain to be studied.

The affect of audio enhancement on vocal timbre

In acoustic singing, performers learn to finely tune their resonance in order to control the spectral output of their voices. However, in amplified singing styles, microphone frequency response, equalization, and other editing tools can affect our perception of resonance. These effects can have positive and negative impacts on the spectral output of a singer’s voice that teachers must be aware of when training Contemporary Commercial Music (CCM) artists. This presentation will include information on how audio equipment can alter the timbre of the voice, affect our perception of registration, and alter the singing power ratio.

Singer's formant in Hindustani classical singers

Context: Since the last two decades, the research has been concentrated on professional voice; there is a curiosity among researchers to find out whether singers (S) are really special in their voice use than nonsingers (NS). Although there have been studies regarding singer's formant in Indian classical singers, underlying physiological adjustments made by singers and its relation with acoustical features need to be studied. Thus, the aims of the present study were to explore the possibility of singer's formant in Hindustani classical singers, to study the physiological adjustments made by the singers, and also to find out the effect of number years of experience on acoustical as well as auditory-visual perceptual parameters. Subjects and Methods: Twenty Hindustani classical singers and ten nonsingers within the age range of 18–50 years were considered for the study. The singers were again grouped into three Subgroups (S1, S2, S3) based on their years of music experience. Acoustical as well as auditory-visual perceptual evaluation was carried out for singers and nonsingers. Results and Discussion: The study revealed that S3 (>10 years of experience) Group had the highest amplitude at 2–4 kHz as well as higher singing power ratio values as compared to S1 and S2. Nasoendoscopic evaluation was done for all the participants by a well-experienced ENT professional. S3 Group had the widest pharyngeal opening. Hence, the results of the present study point out the possibility of occurrence of singer's formant in Hindustani classical singers. Conclusions: The result of the acoustical analysis indicates that there is an effect of years of music experience on the acoustical as well as perceptual parameters. The study highlights the possibility of developing training material for singers to improve their pharyngeal widening.

Effect of Training and Level of External Auditory Feedback on the Singing Voice: Volume and Quality

Previous research suggests that classically trained professional singers rely not only on external auditory feedback but also on proprioceptive feedback associated with internal voice sensitivities. The Lombard effect and the relationship between sound pressure level (SPL) and external auditory feedback were evaluated for professional and nonprofessional singers. Additionally, the relationship between voice quality, evaluated in terms of singing power ratio (SPR), and external auditory feedback, level of accompaniment, voice register, and singer gender was analyzed. The subjects were 10 amateur or beginner singers and 10 classically trained professional or semiprofessional singers (10 men and 10 women). Subjects sang an excerpt from the Star-Spangled Banner with three different levels of the accompaniment, 70, 80, and 90 dBA and with three different levels of external auditory feedback. SPL and SPR were analyzed. The Lombard effect was stronger for nonprofessional singers than professional singers. Higher levels of external auditory feedback were associated with a reduction in SPL. As predicted, the mean SPR was higher for professional singers than nonprofessional singers. Better voice quality was detected in the presence of higher levels of external auditory feedback. With an increase in training, the singer's reliance on external auditory feedback decreases.

The Effect of Traditional Singing Warm-Up Versus Semioccluded Vocal Tract Exercises on the Acoustic Parameters of Singing Voice

This study investigated the effect of traditional vocal warm-up versus semioccluded vocal tract exercises on the acoustic parameters of voice through three questions: does vocal warm-up condition significantly alter the singing power ratio of the singing voice? Is singing power ratio dependent upon vowel? Is perceived phonatory effort affected by warm-up condition? Hypotheses were that vocal warm-up would alter the singing power ratio, and that semioccluded vocal tract warm-up would affect the singing power ratio more than no warm-up or traditional warm-up, that singing power ratio would vary across vowel, and that perceived phonatory effort would vary with warm-up condition. This study was a within-participant repeated measures design with counterbalanced conditions. Thirteen male singers were recorded under three different conditions: no warm-up, traditional warm-up, and semioccluded vocal tract exercise warm-up. Recordings were made of these singers performing the Star Spangled Banner, and singing power ratio (SPR) was calculated from four vowels. Singers rated their perceived phonatory effort (PPE) singing the Star Spangled Banner after each warm-up condition. Warm-up condition did not significantly affect SPR. SPR was significantly different for /i/ and /e/. PPE was not significantly different between warm-up conditions. The present study did not find significant differences in SPR between warm-up conditions. SPR differences for /i/, support previous findings. PPE did not differ significantly across warm-up condition despite the expectation that traditional or semioccluded warm-up would cause a decrease.

Qualitative and Quantitative Measurement of the Singing Voice

Objective: The aim of the study was to clarify the mechanisms underlying the singing voice. Patients and Methods: Forty-eight professional opera singers underwent flexible and rigid endoscopy, spectrographic analysis and perceptual evaluation. Results: The data provided by voice analysis were not as clear and relevant to the aim of our study as those commonly obtained for speech evaluation. Laryngoscopy with rigid and flexible fiber optics and the singing power ratio (SPR) measurement provided more applicable data. Indeed, the former allowed us to assess laryngeal position, the glottic pattern and vocal tract modifications during the actual singing performance. The latter, already recommended by other authors as a reliable vocal emission index, also yielded more relevant information in comparison with the assessment of voice quality. Specifically, SPR provided data directly correlated to both the years of singing activity and the vocal category of each singer (the higher the singing pitch, the wider the vocal extension). More importantly, the data fully reflected the subjective assessment of each phoniatrician. Conclusions: We suggest that the SPR indices can be used as the electroacoustic equivalent of the subjective judgment of vocal focus.

Effect on long-term average spectrum of pop singers’ vocal warm-up with vocal function exercises

This case-control study aimed to investigate if there is any change on the spectral slope declination immediately after vocal function exercises (VFE) vs traditional vocal warm-up exercises in normal singers. Thirty-eight pop singers with perceptually normal voices were divided into two groups: an experimental group (n = 20) and a control group (n = 18). One single session with VFE for the experimental group and traditional singing warm-up exercises for the control group was applied. Voice was recorded before and after the exercises. The recorded tasks were to read a phonetically balanced text and to sing a song. Long-term average spectrum (LTAS) analysis included alpha ratio, L1–L0 ratio, and singing power ratio (SPR). Acoustic parameters of voice samples pre- and post-training were compared. Comparison between VFE and control group was also performed. Significant changes after treatment included the alpha ratio and singing power ratio in speaking voice, and SPR in the singing voice for VFE group. The traditional vocal warm-up of the control group also showed pre–post changes. Significant differences between VFE group and control group for alpha ratio and SPR were found in speaking voice samples. This study demonstrates that VFE have an immediate effect on the spectrum of the voice, specifically a decrease on the spectral slope declination. The results of this study provide support for the advantageous effect of VFE as vocal warm-up on voice quality.

Using the iPhone for Voice Recordings in Laryngology

Objective: 1) Evaluate the adequacy of an iPhone for voice recording enabling acoustic measurement of voice quality, and 2) demonstrate the usefulness of an iPhone-based acoustic analysis for identifying voice aberration and monitoring voice changes after phonosurgery. Method: Twenty-two voice patients, aged from 25 to 92 years (mean, 54.8 years; SD, 18.5 years), read sentences taken from a standard passage. An iPhone (Model 1303) with an internal microphone was used for voice recording. Vowels segmented from the sentences were submitted to an acoustic analysisprocedure to yield measures. Results: Compared with the simultaneous voice recordings via another direct digitization method, the iPhone voice recordings showed relatively high measure-remeasure and acceptable between-system reliabilities for aselection of acoustic measures. In patients with pre- and posttreatment recordings, perturbation measures, including percent jitter, percentage shimmer, and signal-to-noise ratios, and the vowel space area consistently demonstrated positive changes after treatment. Measures of the amplitude difference between the first 2 harmonics, which has been related to breathiness, reflected subtle voice changes due to treatment. Changes in singing power ratio were found to be vowel-dependent, while those in spectral tilt might be gender or pathology-dependent. Conclusion: Voice recordings using the iPhone model with a high sampling rate are adequate for acoustic measurement of speech and voice quality. However, due to large inter-subject variations, most of these measures are more useful for intra-subject than for norm-referenced comparisons inmonitoring the progression of the disorder or treatment effect.

The Acoustic Characteristics of Professional Opera Singers Performing in Chorus Versus Solo Mode

In this study, members of a professional opera chorus were recorded using close microphones, while singing in both choral and solo modes. The analysis included computation of long-term average spectra (LTAS) for the two song sections performed and calculation of singing power ratio (SPR) and energy ratio (ER), which provide an indication of the relative energy in the singer's formant region. Vibrato rate and extent were determined from two matched vowels, and SPR and ER were calculated for these vowels. Subjects sung with equal or more power in the singer's formant region in choral versus solo mode in the context of the piece as a whole and in individual vowels. There was no difference in vibrato rate and extent between the two modes. Singing in choral mode, therefore, required the ability to use a similar vocal timbre to that required for solo opera singing.

Acoustic and Perceptual Appraisal of Vocal Gestures in the Female Classical Voice

Long-term average spectra (LTAS) have identified features in the sounds of singers and have compared different vocal qualities based on energy changes that occur during different vocal tasks. In this study, we compared the perceptual ratings of vocal quality of expert pedagogues with acoustic measures performed on LTAS. Fifteen expert judges rated 24 samples with six repeats of six advanced singing students under two conditions: "optimal" (O), which represented the application of the maximal open throat technique; and "suboptimal" (SO), which represented the application of the reduced open throat technique. LTAS were performed on each singing sample, and two conventional assessments of peak energy height [singing power ratio (SPR)] and peak area [energy ratio (ER)] were calculated on each LTAS. Perceptual scores, SPR, and ER were rank ordered. We then compared perceptual rankings with rankings of acoustic measures (SPR and ER) to assess whether these acoustic measurements matched the perceptual judgments of vocal quality. Although we found the expected significant relationship between SPR and ER, there was no relationship between perceptual ratings of vocal samples or singers based on SPR or ER. These findings suggest that because LTAS measures are not consistent with perceptual ratings of vocal quality, such measurements cannot define a voice of quality. Future research with LTAS to assess vocal quality should consider alternative measures that are more sensitive to subtle differences in vocal parameters.

The Singing Power Ratio as an Objective Measure of Singing Voice Quality in Untrained Talented and Nontalented Singers

A growing body of contemporary research has investigated differences between trained and untrained singing voices. However, few studies have separated untrained singers into those who do and do not express abilities related to singing talent, including accurate pitch control and production of a pleasant timbre (voice quality). This investigation studied measures of the singing power ratio (SPR), which is a quantitative measure of the resonant quality of the singing voice. SPR reflects the amplification or suppression in the vocal tract of the harmonics produced by the sound source. This measure was acquired from the voices of untrained talented and nontalented singers as a means to objectively investigate voice quality differences. Measures of SPR were acquired from vocal samples with fast Fourier transform (FFT) power spectra to analyze the amplitude level of the partials in the acoustic spectrum. Long-term average spectra (LTAS) were also analyzed. Results indicated significant differences in SPR between groups, which suggest that vocal tract resonance, and its effect on perceived vocal timbre or quality, may be an important variable related to the perception of singing talent. LTAS confirmed group differences in the tuning of vocal tract harmonics.