Respiratory function in operatic singing: effects of emotional connection

Breathing and Singing: Objective Characterization of Breathing Patterns in Classical Singers

Singing involves distinct respiratory kinematics (i.e. movements of rib cage and abdomen) to quiet breathing because of different demands on the respiratory system. Professional classical singers often advocate for the advantages of an active control of the abdomen on singing performance. This is presumed to prevent shortening of the diaphragm, elevate the rib cage, and thus promote efficient generation of subglottal pressure during phonation. However, few studies have investigated these patterns quantitatively and inter-subject variability has hindered the identification of stereotypical patterns of respiratory kinematics. Here, seven professional classical singers and four untrained individuals were assessed during quiet breathing, and when singing both a standard song and a piece of choice. Several parameters were extracted from respiratory kinematics and airflow, and principal component analysis was used to identify typical patterns of respiratory kinematics. No group differences were observed during quiet breathing. During singing, both groups adapted to rhythmical constraints with decreased time of inspiration and increased peak airflow. In contrast to untrained individuals, classical singers used greater percentage of abdominal contribution to lung volume during singing and greater asynchrony between movements of rib cage and abdomen. Classical singers substantially altered the coordination of rib cage and abdomen during singing from that used for quiet breathing. Despite variations between participants, principal component analysis revealed consistent pre-phonatory inward movements of the abdominal wall during singing. This contrasted with untrained individuals, who demonstrated synchronous respiratory movements during all tasks. The inward abdominal movements observed in classical singers elevates intra-abdominal pressure and may increase the length and the pressure-generating capacity of rib cage expiratory muscles for potential improvements in voice quality.

The effects of emotional expression on vibrato

OBJECTIVES/HYPOTHESIS

The purpose of this study was to investigate the effect of emotional expression on several acoustic measures of vibrato, including its rate, extent, and steadiness. We hypothesized that singing a passage with emotional content would influence these variables.

STUDY DESIGN

This study used a within-subjects, repeated-measures design. Singer performance under different conditions was analyzed.

METHODS

Ten graduate student singers (eight women, two men) completed a series of tasks including sustained sung vowels at several pitch and loudness levels, an assigned song that was judged to have relatively neutral emotion, and a personal selection that included passages of intense emotion. Vowel tokens were extracted from the recordings and averaged for each task. Dependent measures included the mean fundamental frequency (F0), mean intensity, frequency modulation (FM) rate, FM extent, and measures of FM rate and extent variability.

RESULTS

The FM rate and extent were higher and the modulation variability was lower for the more emotional song than for the sustained vowels. Mean F0 and intensity were higher for the emotional song than for the neutral song.

CONCLUSIONS

Singing an emotional passage influences acoustic features of vibrato when compared with isolated, sustained vowels. The wider dynamic and pitch ranges for emotional passages only partly explain vibrato differences between emotional and neutral singing.

Influence of emotional expression, loudness, and gender on the acoustic parameters of vibrato in classical singers

OBJECTIVES

Vibrato is considered one of the most essential characteristics of the classical singing voice. Vibrato can be acoustically described by the rate, extent, onset, and regularity. The aim of this study was to determine the influence of emotional expression on acoustic parameters of vibrato in classically trained singers.

STUDY DESIGN

A prospective cohort study was performed.

METHODS

Thirty healthy classical singers were recruited for this study, 29 singers met inclusion criteria. Inclusion criteria for this study were as follow: 1) no history of vocal pathology in the past year, 2) to have at least 5 years of classical singing training. Each subject was asked to sing the phrase "I Love You," while expressing four different emotions (tenderness, anger, happiness, and sadness) and without emotion (neutral state). The musical tonality of the phrase was adapted to each singer's vocal classification. Subjects were also recorded at three levels of loudness (pianissimo, mezzo forte, and fortissimo), while expressing each emotion. Acoustical analysis was performed during the vowel /o/ of the word "Love" to determine rate of vibrato, the extent of vibrato, and vibrato jitter.

RESULTS

Vibrato parameters did not vary significantly when different emotions were expressed. However, vibrato jitter and extent did vary significantly between different levels of loudness. Significant differences were also noted in both rate and extent of vibrato when compared between sexes.

CONCLUSIONS

Expression of emotions does not affect the acoustic parameters of vibrato, although some parameters are affected by loudness and gender.

The effects of open throat technique on long term average spectra (LTAS) of female classical voices

In the third of a series of studies on open throat technique, we compared long term average spectra (LTAS) of six advanced singing students under three conditions: 'optimal' (O), representing maximal open throat, 'sub-optimal' (SO), using reduced open throat, and loud sub-optimal (LSO) to control for the effect of loudness. Using a series of univariate repeated measures ANOVAs with planned orthogonal contrasts, we tested the hypotheses that sound pressure level (SPL) and the ratio of spectral energy in peaks and areas between 0-2 kHz and 2-4 kHz would be reduced in SO and LSO compared to O. There were significant differences between SO and LSO but hypotheses were not confirmed for O. These findings do not accord with differences in vibrato extent and onset between O and SO/LSO (Mitchell and Kenny, in press). These results suggest that while LTAS provides information on energy distribution, measuring spectral energy areas appears to be the most sensitive measure of energy distribution between conditions. Plotting the differences between O and SO/LSO pairs of LTAS clearly indicates the areas of spectral change. The findings from this study also indicate that LTAS are not sufficiently sensitive to measure vocal timbre as they were not consistent with perceptual or other acoustic studies of the same samples.

The impact of ‘open throat’ technique on vibrato rate, extent and onset in classical singing

Mitchell, Kenny et al. (2003) identified 'open throat' as integral to the production of an even and consistent sound in classical singing. In this study, we compared vibrato rate, extent and onset of six advanced singing students under three conditions: 'optimal' (O), representing maximal open throat; 'sub-optimal' (SO), using reduced open throat; and loud sub-optimal (LSO), using reduced open throat but controlling for the effect of loudness. Fifteen expert judges correctly identified the sound produced when singers used open throat with 85% accuracy. Having verified the technique perceptually, we used a series of univariate repeated measures ANOVAs with planned orthogonal contrasts to test the hypotheses that frequency modulations associated with vibrato rate, extent and onset would vary outside acceptable or desirable parameters for SO and LSO. Hypotheses were confirmed for vibrato extent and onset but not for rate. There were no significant differences between SO and LSO on any of the vibrato parameters. As vibrato is considered a key indicator of good singing, these findings suggest that open throat is important to the production of a good sound in classical singing.

The influence of fundamental frequency and sound pressure level range on breathing patterns in female classical singing

PURPOSE

This study investigated the influence of fundamental frequency (F0) and sound pressure level (SPL) range on respiratory behavior in classical singing.

METHOD

Five trained female singers performed an 8-s messa di voce (a crescendo and decrescendo on one F0) across their musical F0 range. Lung volume (LV) change was estimated, and chest-wall kinematic behavior (dimensional change in ribcage [RC] and abdominal [AB] wall) was recorded using triaxial magnetometry.

RESULTS

The direction of F0 influence on LV excursion (LVE) varied among singers, but SPL range appeared to be less important than duration to LVE. LVE was generally evenly divided between crescendo and decrescendo. Kinematic patterns differed markedly among singers, despite task consistency, and RC and AB paradoxing was widespread.

CONCLUSION

Each singer maintained her characteristic kinematic pattern regardless of F0 or SPL range, although these did influence aspects of RC and AB behavior. Given the essential role of breathing in classical singing, further work is needed to understand how singers develop their highly individual respiratory strategies and the principles by which each singer's breathing strategy can be optimized.

Effect of facemask use on respiratory patterns of women in speech and singing

PURPOSE

Research into respiratory behavior during singing and speech makes extensive use of standard respiratory and vented pneumotachograph facemasks. This study investigated whether the use of such facemasks would affect respiratory behavior in terms of lung volume (excursion, at initiation and at termination) or duration (of inspiration and of expiration) during speech or singing.

METHOD

The respiratory patterns of 6 females were recorded using uniaxial surface magnetometry during 4 tasks: quiet breathing, a /pa/ syllabic train, reading ("The Rainbow Passage"), and singing a Christmas carol ("Silent night"). Each task was performed in 4 facemask conditions: wearing no facemask, wearing a facemask rim only, wearing a standard respiratory facemask, and wearing a vented pneumotachograph facemask.

RESULTS

No significant effect was found for any of the facemask conditions on lung volume or duration measures during any tasks.

CONCLUSION

The results confirm earlier studies that the vented pneumotachograph facemask does not affect breathing behavior in speech research studies and extends the finding to the study of breathing behavior in singing and to the use of a standard respiratory facemask.

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.