The Sound that Resounds
The end of 2012 brings to a close this year-long exploration of the basics of vocal production. Beginning with the foundations of good posture and breathing, the adventure continued with the mechanics of phonation and registration, and little anatomy thrown in. We now arrive at the finish line. As vocal resonance and articulation are rather inseparable vocal components, what follows is Part 1 of a 2-part article.
Last month, I briefly touched upon the concept of resonant tuning, i.e., shaping the vocal tract to select or ignore certain harmonics of the vocal tone. In this issue, a more elaborate explanation is presented along with the phenomenon of resonance itself and its interconnection with articulation.
The voice is the only instrument in which articulation is a function of resonance. From the Latin word resonare, resonance means to sound again, resound, echo, re-vibrate. Sym-pathetic resonance sets off kindred vibrations with other materials or objects that originate from another source. This occurs in a void; a hollow structure that has volume and openings/exits for sound waves.
Vocal resonance takes place in the vocal tract (VT). From the vocal folds up through to the lips, this curved tube-like structure is made up of a series of “containers”. It includes the epilarynx (the area from the vocal folds to the top edge of the larynx), the pharynx (throat) and the oral or mouth cavity. The size and openings of each of these areas in addition to their relationship to each other, greatly affects the tonal outcome. The average length of the VT is 17.5 cm (McCoy). This number will vary with gender and voice type. The VT is similar to a stereo amplifier, modifying the tone through a filtering system. One of the VT’s main functions is to successfully transfer sound waves from the source, the vocal folds, into the music we hear when someone sings. Vocal efficiency is linked to this conversion of sound waves into acoustic energy – “big vibrations induced by small vibrations” (McCoy). An effective resonating system increases the rate energy is released. More bang for your buck!
Diagram of the Vocal Tract www.webschool solutions. com
A resonant frequency is a natural frequency of a cavity or space. It is a band of concentrated acoustical energy also called a formant. In a container or space with fixed dimensions, the repeating pattern of high to low pressure sound waves results in the same pitch and tonal quality. The VT is a variable space, so its resonant frequencies are in constant flux to keep pace with the alterations in the spacial environmental brought about by pitch and vowel changes. Remember those glasses filled with varying amounts of water? Each had their own pitch or resonant frequency according to the distribution of the air and water in the space.
So why is this important to know?
Because of its pliability, the VT can accom-modate a wide range of acoustical input. Each pitch has its own set of frequencies, the fundamental (the sung pitch) and the over-tones that are a part of its harmonic series. The “single” pitch we hear is actually a complex sound wave. Even though we don’t always hear the individual harmonics, they are recognized by the formants. If the home resonant frequencies of the VT match up with the harmonics of the pitch, it will give those frequencies a boost. Those that do not work within the acoustical structure of the VT will be dampened. This formant tuning or “matching up” of harmonics (also referred to as vowel modification), not only adds color to the sound, it aids in the projection of the voice. This tuning process is influenced by voice size, duration and dynamic level of the tone sung and the frequency itself. If the intensity or pitch increases, the resonator size must also increase. As singers we need to learn how to successfully manipulate the VT to produce the most efficient and beautiful sound through a full range of dynamics without forcing or undue stress.
So how do singers do this?
When we inhale deeply, our larynx drops and the soft palate rises, elongating the VT. As the larynx lowers, it also expands the throat. This lengthening and widening of the VT enriches and deepens the sound. A raised larynx narrows the throat, shortening the VT tube. If coupled with a collapsed soft palate, the sound that emerges is bright and brassy, and most likely, nasal. Hard surfaces such as the hard palate and teeth reflect sound while the softer material of the lips and soft palate absorb it. For example, smiling will brighten a sound; puckering will add warmth. Even what seems to be subtle changes to the VT can make an enormous difference in the sound emitted and its power. The ability to manipulate the VT for optimal resonance on every pitch, takes great skill and lots of practice!
And this is just the beginning …. The effect of articulation upon the acoustical shaping of the VT, especially the oral cavity, is more com-plex and intriguing! In next month’s publication, we will learn how the articulators move to form the consonants and vowels needed to fashion individual words and their effect on resonance, resonant tuning and above all, the communication of the text to the audience.
Some preview material…..
Articulation: the maneuvers made by the articulators in order to adjust the shape of the vocal tract during phonation; helps give phonation acoustic qualities. (Sundberg & Titze).
The lips, jaw and tongue are the main organs of articulation, the tongue being the VIP of the three. Their articulatory movements can manipulate the length, location and degree of constriction within the VT, creating unique patterns of sound waves and reflections. Although the December newsletter will focus primarily on vowels, consonants have an important role to play.
In speaking, consonants and vowels are on equal footing, but during singing, vowels are king, making up 99% of our phonation (Nix). Consonants are considered noise. They pro-duce irregular sound waves and do not project as well as tone, i.e. vowels. However, without consonants to separate the stream of vowels, no understanding of the text is possible. Con-sonants are the transition sounds between vowels and must be produced quickly, with energy and precision, minimizing their effect on the overall vocal timbre. Although vowels are a joy to sing, consonants can be user friendly, setting off those vowels to resonate!
Principles of Voice Production, Titze,I. Prentice Hall. 1994.
Science of the Singing Voice, Sundberg, J. Northern Illinois University Press. 1987
Bodymind and Voice: Foundations of Voice Education, Thurmon, L. EdD & Welch, G. PhD. VoiceCareNetwork, 2000.
Your Voice: An Inside View. McCoy, Scott DMA. Inside View Press. 2004
Vowel Modification, Nix, J & Bozwman, K. Journal of Singing. National Assoc. of Teachers of Singing, 2004, 2007.
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