Soprano, style and voice quality: acoustic and laryngographic correlates




Bateman, Laura Anne

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There are numerous widely varying vocal styles and voice qualities in Western music. Popular music in the 21st century uses a particular voice quality for female voice that is quite different from the trained classical voice quality. Classical voice quality has been the subject of a vast body of research, whereas research that deals with non-classical voice quality and pedagogy is very limited. In order to learn more about these issues, the author chose to do research using a variety of standard voice quality tests to substantiate the existing literature, and perhaps generate new information. This thesis presents a review of the existing literature on voice quality in various different styles of singing: Classical, Belt, Legit, R&B, Jazz, Country and Pop. In addition, this thesis looks at spectral measurements from a small set of voice samples, elicited from a professional soprano. Laryngographic (LGG) data was generated simultaneously with the audio samples. To limit the data set for the scope of this thesis, singing samples using the vowel [i] are selected_ The analysis techniques used in this thesis are Spectrogram, LPC, FFT, and various LGG ratio measurements. The spectral measurements compared include the relative strength of the first two harmonics, the formant locations, relative energy from harmonic strength near the formants, summed energy in two quadrants (0-3000Hz, 3000-5000Hz), and the inharmonic or aperiodic activity seen in each quality. Data from the LGG is used to calculate the contact quotient (the time the vocal folds are in contact divided by the time for one cycle of the vocal fold vibration), speed quotient (the time between maximum contact of the vocal folds and vocal fold separation divided by the time between first contact and maximum contact) and ascending slope (the slope of the contacting phase of the vocal fold wave). The LGG waveform was also visually assessed. The acoustic and LGG data are compared to an auditory analysis by Dr. John Esling (Professor of Linguistics, UVic) and to the subject's descriptions of the physical configurations involved in producing these qualities. Physiological observations obtained from x-ray fluoroscopy & MRI scans of belt and classical voice qualities are included in Appendix B. The intention of the thesis is to reveal more about the workings of these voice qualities. The thesis also serves as a prototype for a series of 10 vowels and running samples that were elicited at the same time. Perhaps, even though this thesis presents a limited data set, it may be useful to pedagogues who are struggling to understand the complexities of the non-classical female voice, as well as to computer programmers and engineers who are developing voice enhancement devices and biofeedback tools.



voice quality, female, soprano, pedagogy