Dissertation/Thesis Abstract

Effects of Vibrato and Pitch-Varied Vocal Models on High School and Undergraduate Singers' Intonation, Intensity, and Use of Vibrato
by Hinkley, Sandy Purdum, Ph.D., The Florida State University, 2017, 117; 10261291
Abstract (Summary)

The purpose of this study was to investigate the effects of vibrato and pitch-varied vocal models on acoustic measures of high school and undergraduate singers’ vocal performance. Participants’ perception of vocal models was also examined to explore a possible relationship between perception and production. The following primary questions guided this research: 1) Is singers’ intonation affected by vibrato or pitch-varied vocal models? 2) Is singers’ vibrato rate affected by vibrato or pitch-varied vocal models? 3) Is singers’ vibrato extent affected by vibrato or pitch-varied vocal models? 4) Is singers’ intensity affected by vibrato or pitch-varied vocal models? Secondary questions under investigation were: 1) Do singers respond differently to vocal models of pitch patterns versus song phrases? 2) Does age and experience influence singers’ response? 3) Do singers perceive the differences in vocal models?

Participants (N = 76) were male (n = 38) and female (n = 38) singers who were undergraduates (n = 40) currently participating in a choral ensemble at the Florida State University or high school students (n = 36) currently enrolled in the choral program at a nearby high school. Participants responded to twelve vocal models of the same gender that were varied in melody, vibrato, and intonation conditions. Vocal models consisted of either a short pitch pattern ( sol-la-sol-fa-mi-re-do) or familiar song excerpt (Are You Sleeping?), both performed on the neutral syllable “tah.” Model melodies were sung in vibrato and minimal vibrato conditions, with each model having a specific 3rd and 5th scale degree that was presented in tune, sharp, or flat (mistuned pitches ± 25 cents relative to equal temperament). After responding to vocal models, participants were asked via written questionnaire if they perceived differences in vocal models and, if so, to describe them.

Audio recordings of participants’ responses were analyzed acoustically, with the specific 3rd and 5th scale degrees in each model analyzed for the dependent measures of intonation, vibrato rate, vibrato extent and intensity. Repeated measures analyses were conducted on the acoustic measures. An alpha level of .01 was used in all statistical tests. Written responses on the questionnaire were analyzed for keywords reflecting vocal technique or musical elements. Keywords were then identified and coded for frequency of response.

Significant differences in intonation were found, with responses to minimal vibrato models performed more flat than responses to vibrato models. Main effects were also found for gender, with male participants showing overall more flatness than females. Responses to pitch-varied models tended towards flat intonation, with flat models producing the greatest deviation particularly with male participants. Two interactions, both involving melody condition of models, also produced differences in intonation.

Significant differences in measures of vibrato rate and extent were also observed. Vibrato rates were faster and vibrato extents were wider in response to vibrato models. High school participants responded with similar vibrato rate and extent to both vibrato model conditions, whereas undergraduates responded with significantly faster vibrato rate and wider extent to vibrato models. Undergraduate vibrato rates were similar between genders, however high school males were significantly slower in vibrato rate than high school females.

Intensity results for both high school and undergraduate participants showed significantly higher intensity levels for 5th scale degrees than 3rds. High school males performed both scale degrees at similar intensity levels, while high school females sang 5ths with higher intensity. Significant differences in intensity were also found with undergraduates, with responses to vibrato models yielding higher intensity. Male undergraduates were found to sing with higher intensity in response to vibrato models, whereas females sang with similar intensity between vibrato-varied conditions. Interactions involving scale degree or melody condition of models also produced significant differences in intensity.

Analysis of written questionnaires showed that 71 (93%) participants perceived differences in models. The most frequently used keyword(s) was vibrato/straight tone, with 36 participants (51%) noting this as a perceived difference between models. Timbre/tone quality was the next most used word(s) by 13 participants (17%), followed by intonation/pitch used by 12 participants (15%). More males noticed changes in tone quality, intonation, and vowels than females, whereas the latter recognized vibrato changes more than males. Undergraduates perceived vibrato changes and intonation differences more than high school participants.

Many complex factors were thought to contribute to results of this study, including perception, experience, vocal development, and vocal production. While some findings support prior research, other results raise questions that warrant additional investigation. Implications and ideas for future inquiry are discussed.

Indexing (document details)
Advisor: Geringer, John M.
Commitee: Bowers, Judy K., Geringer, John M., Madsen, Clifford K., Moore, Christopher R., Thomas, Andre J.
School: The Florida State University
Department: Music
School Location: United States -- Florida
Source: DAI-A 78/11(E), Dissertation Abstracts International
Subjects: Pedagogy, Music education, Secondary education
Keywords: Choral pedagogy, Intonation, Modeling, Pitch accuracy, Vibrato, Vocal models
Publication Number: 10261291
ISBN: 9781369870015
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