Dear Mike and Vocalisters:
>Your asked:
> do you think effect of this 'support' (the acoustic
>properties of the sound in the vocal
>tract can provide a kind of acoustic support for the vocal folds)
>purely psychological or, is
>there an actual physical phenomenon as well, however slight? (i remember we
>briefly talked about standing waves a few years ago and, at the time, i
>wondered if they had a physical effect on the behavior of the vocal folds.)
I am including a former post I made in response to the concept about
the above. "Inertance" is the term coined by Titze to explain this
phenomenon.
"Although the phenomenon of airflow through a reducing diameter tube and
the resultant reduction of lateral air pressure at the location of the
reduced diameter is a source of energy that assists in the closing of the
vocal folds during each oscillation, it is not sufficient in itself to
provide a sustained oscillation of the vocal folds, according to Titze.
The vocal fold's inherent elasticity is also not sufficient to sustain
oscillation. The concept of "flow phonation" is built around both of these
ideas and, although they do occur and are a part of the process of
oscillation, they do not represent sufficient, nor sustained, energy input
to the vocal folds such that they are able to maintain continued oscillation
In his book, Titze describes another source of energy conservation that
does provide the "support" to maintain continuous oscillation. It is
concerned with the inertia of the air within the vocal tract itself,
particularly just above the glottis and the ary-epiglottic chamber or, more
particularly, the differences in inertia of the air between these areas and
the balance of the pharynx and mouth. This inertia, which he calls
"inertance" provides a kind of pneumatic "spring" that helps reduce the
loss of mechanical energy which is input into the system by the initial
movements of the vocal folds and is able to redirect that conserved energy
back into the vocal folds tissue to assist in the support a sustained
oscillation.
This concept of "inertance" implies that the actual shape of the vocal
tract has a direct effect on the efficiency of vocal fold oscillation.
Because vocal tract shape is adjustable and must be adjusted to achieve
vowel differences, it is only a small step from this to assume that vowel
selection and vowel modification have a major effect on vocal fold
function.
Vowel selection and "vowel purity" have always been a major concern in
traditional voice teaching, not so much because such "purity" is needed for
language understanding, but rather because such vowel concerns provide the
purity of tone which is the hallmark of all great voices and such vowel
concerns develop a voice that is more efficient and more capable of meeting
the demands required in the performance of classic vocal music."
--
Lloyd W. Hanson
|
|  |
