De las señales de indicación Artículo 158. Objeto y tipos

As mentioned above, the gap between the vocal processes can be gradually adjusted. Herbst (2011) has provided new insight into how this parameter can be configured, and how it affects the registers. His work is influenced by Sundberg’s (2001) descriptions of four phonation types, which is a categorization of the degree of vocal fold adduction. Sundberg (2001) writes about the phonation types pressed, neutral, flow and breathy, which occur on a gradient from the firmly closed glottis to a glottis that does not close completely in each cycle. Pressed phonation comes from vocal folds that are pressed together along their whole length, with a high subglottic pressure underneath. Flow phonation is recognized as having the lowest subglottal pressure and is used, for instance, in professional classical singing. This is the last type of phonation on the gradient, with a fully closed glottal configuration, and if the tension in the vocal folds is released just a little more, you get a leaky and thus breathy type of phonation. Neutral phonation is usually used in speech and is found somewhere between pressed and flow phonation. As far as I know, these terms are not interchangeable with register terms such as chest voice or head voice, but are types of phonation that can be used almost regardless of register.

Herbst (2011) thus divides glottal behavior into two groups, where registration is one adjustable parameter, and voice quality or phonation type is the other. He found that both untrained singers (who received only one very short lesson lasting 30 minutes where they learned the targeted phonation types in the two relevant registers) and trained singers were able to produce what he calls adducted and abducted chest, and adducted and abducted

falsetto. These terms can be explained like this: The adducted phonation types occur when

there is intercartilaginous adduction, possibly by contraction of the LCA and IA muscles, ensuring the closing of the vocal processes. When combined with thyrovocalis activation, which is responsible for the membranous medialization, we get the adducted chest register. In the case of less or no contraction in the thyrovocalis, adducted falsetto is the suggested label.

The abducted phonation types occur when there is little or no muscle activity closing the cartilaginous part of the vocal folds, in other words an open vocal process gap. This gap can be seen in both abducted chest, where the thyrovocalis ensures membranous medialization but with no closing of the intercartilaginous gap, and in abducted falsetto where there is neither membranous medialization nor intercartilaginous closing.

Herbst (2011, p. 47) warns against using solely closed quotient as an indicator of registers in singing. As mentioned earlier in this thesis does high CQ values indicate chest voice, whereas lower CQ values may indicate a head voice register. In a study by Herbst, Qiu, Schutte and Švek (2011, p. 2259), the CQ values in adducted falsetto were actually higher or equal than in the abducted chest mode in eight of their subjects. This means that a person is able to produce falsetto tones that have a higher CQ than the tones produced in chest voice with an open vocal process gap. To their knowledge, this was a new finding and had not been reported in the scientific literature before.

To summarize, Herbst (2011) states that “both chest and falsetto register can be produced either with glottal closure, or without, depending on vocal fold cartilaginous adduction” (p. 30). He also points out that “these fine-controlled muscular adjustments allow experienced singers to create a large variety of sound timbres at the glottal level, increasing their

expressional freedom within the aesthetical boundary conditions of their chosen singing style” (p. 50). In other words, singers are not constricted to one of these four glottal configurations but can freely choose between the voice qualities along these two major axes: cartilaginous adduction, in the form of phonation types, and membranous medialization, in the form of registers.

Before leaving Herbst (2011) altogether, I would like to share his thoughts on a model case from the singing studio. The example is relevant both because many beginner students have this particular problem, and because Herbst suggests laryngeal explanations for the ‘whys and hows’ of the problems in the case. He writes about how untrained female singers have a tendency to sing above the primo passaggio either in adducted chest register or in abducted falsetto, meaning either in a pressed and pushed chest register or in a too soft and breathy falsetto register. This is supported in a later study by Herbst, Hess, Müller, Švek and Sundberg (2015, p. 400). He further gives an explanation as to why it is so difficult to switch from adducted chest to adducted falsetto. I adopt Herbst’s terminology here, using falsetto, but in English I would usually prefer to use the term ‘head’ when talking about this female register:

When changing from chest to falsetto register, the TA muscle relaxes, and thus membranous medialization is reduced. The resulting decrease of overall vocal fold adduction could be counteracted by a slight increase of cartilaginous adduction via the LCA and IA muscles, in order to keep the timbral change at a minimum. Such maneuver (decreasing TA whilst increasing LCA and IA activity, respectively) is, however, both ambivalent and complex: Since the three involved muscles are all innervated by the recurrent laryngeal nerve, the required level of fine control might be hard to reach by some singers. (Herbst, 2011, p. 50)

This description is followed by a pedagogical strategy that takes into account both the adduction/abduction issues and register configurations.

A valid pedagogical strategy would try to establish the aDducted falsetto at higher pitches (around Bb4 to F5), via calling (but not shouting) at vowel /u/, or using “primal sounds” … This sound quality could then be applied to other vowels and pitches all the way down to the primo passaggio. When attempting to achieve a successful transition from (aDducted) chest to aDducted falsetto on ascending scales, there is the danger that the singer “gets stuck” in the chest register. In order to avoid this, it is advisable that ascending scales are only sung when:

a) the student reliably succeeded to produce aDducted falsetto in the primo passaggio on descending scales; and

b) s/he managed the falsetto-chest register transition at the primo passaggio without abrupt timbral changes. (Herbst, 2011, p. 50)

This procedure may have resemblances to strategies mentioned in the CCM literature, where calling exercises like “Hey Taxi” (Jared Trudeau, 2016) are commonly used. However, the latter triggers a heavier voice production, and may in some cases be quite distinct from what is sketched above. Herbst (2011) does not indicate how much adduction and how much chest or head register respectively should be used in the adduction, but by recognizing the gradual lines in which singers can sing with great variety both in pitch, loudness and timbre, I believe this method works for classical singers as well as CCM singers as long as genre-appropriate features are accounted for.