Overall and posterior glottal adduction in singing

Christian Herbst, J.G. Švec, Q. Qiu & H.K. Schutte

It is known that glottal adduction can be adjusted both posteriorly by PCA/LCA/IA muscles as well as in overall by the TA muscles. A previously conducted pilot study on a baritone suggested that an independent control of the posterior and TA adduction allows achieving better flexibility in controlling the singing voice quality. The goal of this study was to design phonatory exercises to isolate these two types of glottal adduction. Four extreme phonation types were targeted, using the chest and falsetto registers with and without breathiness: a) “naďve” falsetto (breathy), b) “resonant falsetto”, c) “light chest” (breathy) and d) “dramatic/operatic chest”. 6 female and 6 male singers and non-singers were asked to imitate the instructor (i.e. the baritone who participated in the previously conducted pilot study), producing those 4 phonation types at a pitch located within the range of the chest/falsetto register transition (C#4 to F4). In order to maintain the desired registration (chest or falsetto), the target notes were reached by singing a descending (for falsetto) or ascending (for chest) scale of five notes. (The subjects were asked not to “blend or mix the registers”). The phonation was monitored by videostroboscopy, videokymography (VKG), electroglottography (EGG) and audio recording.
The results showed distinct laryngeal configurations and vocal fold vibration characteristics for the four phonation types. All subjects showed less adducted posterior glottis in the two breathy phonation types than in the non-breathy phonations. In some cases, the arytenoid
processes were clearly vibrating during the breathy phonations. All subjects had mucosal waves and sharp lateral peaks in VKG when phonating in “dramatic/operatic chest” voice.
In 9 subjects, mucosal waves of some degree were found in all phonation types, i.e.,even
in both the falsetto phonations.
The findings of this study suggest that the designed phonatory exercises can be used to Produce 4 extreme types of singing voice and to train singers to gain an independent control of the voice register and glottal adduction, making the voice more flexible. The data also showed that the closed quotient can in some subjects achieve larger values in “resonant falsetto” than in “light chest” phonations, implying that the closed quotient is not a sole indicator of the voice register in singing.

Herbst, Švec, Qiu & Schutte: March 2007

Christian Herbst (herbst@ccrma.stanford.edu)
Tölzer Knabenchor, Munich/Germany
Jan G. Švec (svecjan@vol.cz)
Qingjun Qiu (q.qiu@med.umcg.nl)
Harm K. Schutte (h.k.schutte@med.umcg.nl)
Groningen Voice Research Lab, Dept. Biomedical Engineering,
University of Groningen,
the Netherlands