發聲機轉:phonation mechanism

˙phonation physiology 

(1)vibratory behavior of vocal folds àpitch/loudness/quality

(2)larynx àphonational threshold pressure

(3)tissue of vocal folds àstiffness/mass

(4)the shape of the glottal region à vocal fold closure

˙Basic concepts of laryngeal phonatory behavior

  (1)vocal folds vibration

 a) delay action： airflow & v.f. tissue

 b) asymmetrical driving force：the pressure  between supraglottal region & subglottal region

  

   1.converging shape /\ (subglottal pressure克服tissue阻力)

      1)-delayed action of the tissue on top of the vocal fold

      2)-intraglottal pressure & driving force

      3)-transfer energy to vocal fold & oppose frictional energy loss

      4)-intraglottal pressure in phase w/ tissue velocity

   2.intraglottal pressure↑& driving force需

   3.diverging shape \/ 

      repeat1-1)~4) 

 4.intraglottal pressure↓& driving force

 5.driving force

(2) vibration threshold pressure

   1.thickness (↓à threshold↑)

   2.tissue damping & viscosity (↑à threshold↑)

   3.mucosal wave velocity (↑à threshold↑)

   4.degree of vocal fold prephonatory adduction(wide↑à threshold↑)

  (3) fundamental frequency control

   1.v.f. length & tension↑à F₀↑

   2.v.f. mass↑à F₀↓

   3.subglottal pressure↑à F₀↑

 4.thyroarythenoid muscle activity à↓/↑F₀-frequency & intensity level

 5.extrinsic laryngeal muscle activity

     1) F₀↑--hyoid & thyroid forward

     2) F₀↓--shorter  between  the  hyoid & thyroid

  (4)intensity control (intensity, loudness, volume, vocal power)

   1.Subglottal pressure

   2.Glottal flow waveform

   3.Glottal geometry

   4.Vocal Tract

  (5)quality control

   1.perceptually

   2.physiologically --Glottal flow  waveform

   3.acoustically--Spectrum

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