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From:  "Lloyd W. Hanson" <lloyd.hanson@n...>
"Lloyd W. Hanson" <lloyd.hanson@n...>
Date:  Sun Jul 15, 2001  10:04 pm
Subject:  [vocalist] Re: falsetto (was lower register)


Wim:

Thanks for the post. I don't disagree, but you are not addressing a
key element in the changes from "heavy ('rolling' movement with high
vertical phase difference and high closed quotient) or light (lateral
movement with little vertical phase difference and lower closed
quotient). The vocal folds are made up of 4 (some say 5) layers.
From median laterally they are: mucosal membrane, vocal ligament and
two thyroarytenoid muscles ( I do not have my reference materials
here so I must generalize). The "little vertical phase difference"
description you mention is the result of the vocal ligaments being
the primary resistance elements to the lengthening of the
crycothyroids. The "rolling movement with high vertical phase
difference" of which you speak is the result of the active
involvement of the two thyroarytenoid muscles.

Open and closed quotient has a very strong effect on the tonal
quality but this is usually described as "pressed" phonation (vocal
folds closed during most of the oscillation cycle) or breathy
phonation (vocal folds open during most of the oscillation cycle) aor
the desirable correct phonation (a more or less equal balance between
closed and open of the folds during the oscillation cycle). It is
possible to use any of these quotients in either light or heavy
mechanism. Tthe light or heavy is more a description of the
thickness of the vocal folds and the portion of the vocal folds that
is oscillation than it is a description of the closed or open
quotient.

Also the is no function of which I am aware in which there is
"completely dominant vocalis (or) completely dominant cricothyroid.
Depending any use, one or the other of these muscle will be dominant
but not without some antagonistic action of the other.

You also state:
"Also it seems that the point at which the mode transition will
occur is not exclusively determined by the ratio between the
activity of the two muscles. Other factors such as adduction
force / subglottal pressure as well as resonance can influence the
point of transition."

I agree. Especially the effect of resonance on the points of
passaggio change. The vowel chosen can change the passaggio point as
much as a major third to a fourth because of the effect the standing
wave has vocal folds, that is, the acousitic load that applies to the
vocal fold.

Titze, in his book, stresses the idea of vocal ligament and vocalis
muscle and the affect of acoustic load on the vocal folds
--
Lloyd W. Hanson, DMA
Professor of Voice and Vocal Pedagogy, Emeritus
Director of Opera-Theatre, 1987-1997
School of Performing Arts
Northern Arizona University
Flagstaff, AZ




  Replies Name/Email Yahoo! ID Date Size
13198 Re: falsetto (was lower register) Wim Ritzerfeld   Mon  7/16/2001   4 KB

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