The hard facts are in: the facial area as a significant producer of vocal resonance is a difficult position to defend from a physiological perspective— experiential testimonials notwithstanding. If this is true, then mask sensations are poor guides to proper voice production. We could understand this view more clearly by differentiating between what I call “primary resonance” and “secondary resonance.” Primary resonance and vowel sounds are the same phenomenon and result from laryngeal sound frequencies traveling through, and being modified by, the flexible structures and actions of pharynx, soft palate, and oral cavities.
Secondary resonance, by contrast, forms in the nasal passages for the production of certain consonants like m and n, and to a much lesser extent for general vowel production. The intensity of secondary resonance changes from person to person and is based upon the degree to which the soft palate naturally rises during speaking and singing. As the soft palate continually rises and falls in singing (and speaking), it closes and opens the passageway between the throat and the nasal cavities. During nasal breathing, for instance, the soft palate is down (relaxed), which allows air to move freely from the nasal cavities to the throat, and breath to move from the lungs to the outside. During eating, singing, and speaking, on the other hand, the soft palate rises to restrict the opening into the nasal passages.
The movement of the soft palate is affected in a number of ways, most predominantly by anatomical characteristics. Some people may have a stronger, more flexible soft palate, which means that it may rise with greater ease, thereby blocking off the passageway to the nasal cavities more effectively and efficiently; this would result in a reduction of secondary resonance.
There are also cultural differences. American, southern dialects, for instance, often have a more nasal sound in their vocalizations. This signifies a more consistently lowered soft palate, which means increased secondary resonance. Of course, certain singing styles, such as country music, may use more secondary resonance than, say, opera singing, where primary resonance is dominant.
Even given the important role that secondary resonance plays in aspects of phonation, it is negligible in comparison to primary resonance. In point of fact, secondary resonance is dependent on primary resonance to the extent that the sound waves that reach the nasal cavities have already had the benefit of being resonated—“filtered”—first by the larynx and pharyngeal cavity.
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