Vocal resonance

McKinney defines vocal resonance as "the process by which the basic product of phonation is enhanced in timbre and/or intensity by the air-filled cavities through which it passes on its way to the outside air." Throughout the vocal literature, various terms related to resonation are used, including: amplification, filtering, enrichment, enlargement, improvement, intensification, and prolongation. Acoustic authorities would question many of these terms from a strictly scientific perspective. However, the main point to be drawn from these terms by a singer or speaker is that the result of resonation is to make a "better" sound, or at least suitable to a certain esthetical and practical domain.

The voice, like all acoustic instruments such as the guitar, trumpet, piano, or violin, has its own special chambers for resonating the tone. Once the tone is produced by the vibrating vocal cords, it vibrates in and through the open resonating ducts and chambers, or the vocal tract, being sometimes associated to different regions of the body : chest, mouth, nose, "mask", and head.

In more symbolic/perceptual way, rather than physical, the various terms applied can represent vocal "colors" in a continuous scale, from dark or chest resonance to bright or head/nasal resonance. We may call this spectrum a resonance track. In the lower range, the chest resonance or dark color predominates; in the middle range, the mouth-nasal resonance is dominant; in the higher range, the head-nasal resonance (bright color) predominates. The objective of using such images by several teachers and coaches is to achieve command of all the "colors of the spectrum" which, ultimately, may allow greater scope of emotional expression. The emotional content of the lyric or phrase suggests the color and volume of the tone and is the personal choice of the artist.

There are some singers who are recognized by their pronounced nasal quality and others noted for a deep, dark and chesty sound and still others for their breathy or heady sound, and so on. In part, such individuality depends on the structure of the singer's vocal instrument, that is, the inherent shape and size of the vocal cords and of the vocal tract.

The quality or color of a voice also depends on the singer's ability to develop and use various resonances by controlling the shape and size of the chambers through which the sound flows. It has been demonstrated electrographically in the form of "voice-prints" that, like fingerprints, no two voices are exactly alike.

In a technical sense resonance is a relationship that exists between two bodies vibrating at the same frequency or a multiple thereof. In other words, the vibrations emanating from one body cause the other body to start vibrating in tune with it. A resonator may be defined as a secondary vibrator which is set into motion by the main vibrator and which adds its own characteristics to the generated sound waves.

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Wikipedia