| To: "VOCALIST" <vocalist> Subject: Re: the Physics of Music Date sent: Tue, 18 Jan 2000 21:43:43 -0500 Send reply to: VOCALIST <vocalist>
-----Original Message----- From: David Menzies To: vocalist <vocalist> Date: Tuesday, January 18, 2000 8:29 PM Subject: Re: the Physics of Music
>Jenni writes >"In a class in the physics of music, my professor (who is not too familiar >>with Western Music being from India) insists that vibrato of all types is >>made and artificial. >>Does anyone who has more of a science background than I have any ideas as >>to how I could make him see the musicians' side of things?
Jenni,
According to Vennard, a study conducted by Mason and Zemlin reveals that intermitent innervation signals to the crycothyroid muscles (responsible for pitch) is the cause for vibrato as quantified in electromyographic analysis. In other words, the bioelectrical signal from the brain which causes the cryco-thyroid to stretch the vocal cords for pitch is not one (1) continuous signal which maintain a rigidly stable cord length. Instead the muscle behaves like other skeletal muscles and has a "twitch" period which includes precontraction, contraction and relaxation. It would be logical that there would be pitch variants during the relaxation phase of the twitch. The innervation of the crico-thyroid under electromyographic analysis suggests between six and seven stimuli per second which coincides with the rate of a normal vibrato.
A wobble on the other hand occurs when muscles of the larynx (both intrinsic and extrinsic) are put under such stress as to become tired. In such a state, like a stretched-out arm tired of holding a heavy weight, the mechanism or parts of it begin to tremble. That tremble is super-imposed by hyper-activity in several of the muscles of the mechanism. Wobbles, in my experience, can be reversed, but often require lots of time for muscular retraining and recoordination. Feel free to pass this information to your scientifically minded physics teacher.
If he requires the sources for this information, suggest: Vennard. Singing: The Mechanism and the Technic (Par. 694-720). Also Powers, Scott. Exercise Physiology: Theory and Application to Fitness and Performance (Chapter 8).
I'm sure Miller and others deal with the subject.
I hope this helps.
JRL.
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