Donald Miller 1

1 EGGs for Singers, NA, Roden

There is a great deal of potentially useful information, particularly for practitioners of the singing voice, in the glottal closed quotient (CQ), the percentage of the glottal cycle in which airflow is interrupted by closed vocal folds. What hinders taking advantage of this information is the difficulty in measuring the CQ. In contrast to various invasive methods, which can disrupt customary singing voice production, the electroglottograph (EGG), which reflects the modulation of vocal-fold contact, offers the possibility of routine non-invasive measurement.

 

Identifying glottal closing in the EGG signal in a full singing voice is relatively unproblematic, but glottal opening is another matter. This presentation offers a method of determining the "effective closed phase" (defined as the portion of the glottal cycle in which the subglottal and supraglottal spaces are acoustically uncoupled) by careful comparison of the EGG waveform with the temporally aligned audio wave from a head-mounted microphone, facilitated by the software VoceVista.

 

At the top of what is usually called the chest register, a common type of classically trained male singing voice makes some critical adjustments that one does not find in the usual speaking voice. These can lead to a remarkable reduction of the open phase of the glottal cycle, the consequence of which is the organization of the phases of the audio wave around glottal opening, rather than around closing, which is the rule in phonation with a more modest closed quotient.

 

Such high effective closed quotients, which without forcing readily exceed 75%, help explain certain characteristic features of the male classical singing voice: for example, how singers cope with the passaggio that leads to the (non-falsetto) upper extension of the singing range; also, the enhancement of selected high-frequency components for vocal quality and "carrying power." The presentation shows computer-based feedback for monitoring these adjustments. Such feedback, together with the understanding required to interpret it, is an instance of the major contribution that science and technology are making to traditional voice pedagogy.

 

Key words: electroglottograph, closed/open quotient, singing pedagogy, VoceVista