Cognitive Science Program

Spectrum Effects of a Velopharyngeal Opening in Singing (2018)
Brian P Gill, Jessica Lee, Filipa M.B. Lã, Johan Sundberg
Journal of Voice,

Abstract

The question whether or not a velopharyngeal opening is advantageous in singing has been discussed for a very long time among teachers of singing. The present investigation analyzes the acoustic consequences of a large, a narrow, and a nonexistent velopharyngeal opening (VPO). A divided flow mask (nasal and oral) connected to flow transducers recorded the nasal and oral DC flows in four female and four male classically trained singers while they sang vowel sequences at different pitches under these three experimental conditions. Acoustic effects were analyzed in three long-term average spectra parameters: (i) the sound level at the fundamental frequency, (ii) the level of the highest peak below 1 kHz, and (iii) the level of the highest peak in the 2–4 kHz region. For a narrow VPO, an increase in the level of the highest peak in the 2–4 kHz region was observed. As this peak is an essential voice component in the classical singing tradition, a narrow VPO seems beneficial in this type of singing.

Voice pedagogy—what do we need? (2015)
Brian P Gill, Christian Herbst
Logopedics Phoniatrics Vocology, 41 (4), 1-6

Abstract

The final keynote panel of the 10th Pan-European Voice Conference (PEVOC) was concerned with the topic ‘Voice pedagogy—what do we need?’ In this communication the panel discussion is summarized, and the authors provide a deepening discussion on one of the key questions, addressing the roles and tasks of people working with voice students. In particular, a distinction is made between (1) voice building (derived from the German term ‘Stimmbildung’), primarily comprising the functional and physiological aspects of singing; (2) coaching, mostly concerned with performance skills; and (3) singing voice rehabilitation. Both public and private educators are encouraged to apply this distinction to their curricula, in order to arrive at more efficient singing teaching and to reduce the risk of vocal injury to the singers concerned.

Voice Source Variation Between Vowels in Male Opera Singers (2015)
Johan Sundberg, Filipa M.B. Lã, Brian P Gill
Elsevier. 30 (5), 509-517

Abstract

Objectives: The theory of nonlinear source-filter interaction predicts that the glottal voice source should be affected by the frequency relationship between formants and partials. An attempt to experimentally verify this theory is presented. Study design: Glottal voice source and electrolaryngograph (ELG) signal differences between vowels were analyzed in vowel sequences, sung at four pitches with the same degree of vocal loudness by professional opera singers. In addition, the relationships between such differences and the frequency distance between the first formant (F1) and its closest partial were examined. Methods: A digital laryngograph microprocessor was used to simultaneously record audio and ELG signals. The former was inverse filtered, and voice source parameters and formant frequencies were extracted. The amplitude quotient of the derivative of the ELG signal (AQdELG) and the contact quotient were also compared. Results: A one-way repeated-measures ANOVA revealed significant differences between vowels, for contact quotient at four pitches and for maximum flow declination rate (MFDR) at three pitches. For other voice source parameters, differences were found at one or two pitches only. No consistent correlation was found between MFDR and the distance between F1 and its closest partial. Conclusions: The glottal voice source tends to vary between vowels, presumably because of source-filter interaction, but the variation does not seem to be dependent on the frequency distance between F1 and its closest partial.

Maximum Averaged and Peak Levels of Vocal Sound Pressure (2013)
Braxton Boren, Agnieszka Roginska, Brian P Gill,
135th Audio Engineering Society Convention, At New York, NY,

Abstract

This work describes research on the maximum sound pressure level achievable by the spoken and sung human voice. Trained actors and singers were measured for peak and averaged SPLs at an on-axis distance of 1 m at three different subjective dynamic levels and also for two different vocal techniques ('back' and 'mask' voices). The 'back' sung voice was found to achieve a consistently lower SPL than the 'mask' voice at a corresponding dynamic level. Some singers were able to achieve high averaged levels with both spoken and sung voice, while others produced much higher levels singing than speaking. A few of the vocalists were able to produce averaged levels above 90 dB A , the highest found in the existing literature.

JVoiceIntonation 2013 (2013)
Johan Sundberg, Filipa M.B. Lã, Brian P Gill

Formant Tuning Strategies in Professional Male Opera Singers (2013)
Johan Sundberg, Filipa M.B. Lã, Brian P Gill
Journal of Voice: official journal of the Voice Foundation, 27 (3), 278-288

Abstract

The term "formant tuning" is generally used for the case that one of the lowest formant frequencies coincides with the frequency of a source spectrum partial. Some authors claim that such coincidence is favorable and belongs to the goals of classical opera voice training, whereas other authors have found evidence for advising against it. This investigation analyzes the relationships between formant frequencies and partials in professional singers, who sang scales on the vowels /a/, /u/, /i/, and /ae/ in a pitch range including the passaggio, that is, the fundamental frequency range of approximately 300-400Hz, applying either of the two singing strategies that are typically used (1) in classical and (2) in nonclassical singing, respectively. Formant frequencies of each note in the scales were measured by inverse-filtering the acoustic signal. In the classical style, the first formant tended to be lower than in the nonclassical style. Neither the first nor the second formant tended to change systematically between scale tones, such that on some scale tones either or both formants was just below, just above, or right on a spectrum partial. In many cases, singers produced similar spectrum characteristics of the top tones of the scales with different first and second formant frequencies. Regardless of whether the first formant was slightly lower, slightly higher, or right on a partial, the properties of the voice source did not seem to be affected.

Professional male singers' formant tuning strategies for the vowel /a/ (2011)
Johan Sundberg, Filipa M.B. Lã, Brian P Gill
Logopedics, phoniatrics, vocology, 36 (4), 156-67

Abstract

Certain spectrum characteristics have been identified as important for register equalization around the male passaggio, an effect ascribed to formant tuning although descriptions of formant tuning diverge. Eight professional singers sang scales including their passaggio range on different vowels, applying two formant tuning strategies as found in () classical and () non-classical singing. Formant frequencies were measured using inverse filtering. Results revealed differences between the two strategies. For the classical formant tuning, systematic changes of formant frequencies with pitch were observed. For the highest note sung on /a/, was below the second partial and in the vicinity of the third. Similar spectrum characteristics were achieved by different and values between singers.

Formant strategies in professional male singers (2011)
Johan Sundberg, Filipa M.B. Lã, Brian P Gill
The Journal of the Acoustical Society of America, 129 (4), 2581

Abstract

Singers use formant tuning to avoid discontinuities in voice quality between registers. Around the passaggio, a set of spectrum characteristics has been identified as important to achieve this register equalization. Previous studies suggest different formant tuning strategies in male voices. The present investigation attempts to corroborate these suggestions experimentally. Eight professional tenor or baritone singers sang ascending scales on the vowels [a, æ, i, u] ending on pitches F4, F4, or G4 (350, 370, and 392 Hz, respectively) and including their passaggio notes. These scales were sung with two different formant strategies: (a) as in their normal classical singing technique and (b) as in a non‐classical, musical theatre style. Formant frequencies were measured using the custom made DECAP inverse‐filtering software (GRANQVIST). Results revealed formant tuning differences between the two styles. For the classical singing technique, systematic changes of formant frequencies with pitch were observed. For the back vowels F1 was adjusted to a frequency below the second partial and F2 to the vicinity of the third, confirming previous observations. Formant frequencies were often quite close to a partial. The major spectrum characteristics could be accurately replicated by synthesis applying the source filter theory of voice production.