Our voice is created by the voice box. When the voice comes up from the lungs the vocal cords to vibrate and continue up through to the mouth.
The voice box is within the larynx.
Phonation is production of sound by the voice box.
Larynx essentially has three functions
• Sound production
• Air passage for breathing
• Protecting the air passage during swallowing.
Vocal cords are the soft tissues mainly responsible for the vibratory component of the voice.
Glottis is the opening between two vocal folds and closes during the swallowing and sound production.
The spoken words are recreated by three components
• Voice sound and basic sound produced by the voice folds. This sound is often described as buzzy.
• Resonance of sound and amplification is modified by sound retraction.
• Articulation produces recognizable sound this is created by voice articulators like soft palate, tongue and lips.
Voice mechanism is created by three subsystems each with specific roles.
Subsystem Organs involved Role.
Air pressure system Diaphragm
Lungs Provides air pressure to bring about vibration in the folds.
Vibratory system Larynx (voice box)
Vocal fold Vocal folds vibrate change air pressure sound waves often described as buzzy .
Varies the pitch of sound.
Resonating system. Vocal tract (pharynx)
Nasal passage Change buzzy sound to recognizable voice of a person.
Functions of the voice box
• Breathing opening of the glottis
• Cough reflex close glottis and open it.
• Swallowing closing of glottis
• Voice creation close the glottis and adjust the vocal tension
The process of voice involves three steps.
air is moved out from lungs and towards the vocal cords due to the coordinated action of diaphragm, abdominal muscles, chest muscles rib cage and vocal cord vibrations. Voice folds use muscles, nerves and cartilage to create sound.
Vibratory cycle occurs repeatedly and each cycle is as follows.
• Column of air pressure opens at the bottom of the vocal folds.
• Column of air continues to move upwards towards the top of the vocal folds and opens at the upper most.
• Bernoulli’s effect is created by the low pressure caused by the upward moving column causing the bottom folds to close followed by the top one.
• Closure of the air column releases a pulse of air.
The cycle repeats.
Rapid air pulses created by repeated vibratory cycles produced a sound that is just buzz.
This gets amplified and modified voice tracts resonators producing voice as we recognize it.
• Loudness increases in air flow blows vocal folds wider apart which stay apart longer during a vibratory cycle
• Pitch increases in frequency or vocal fold vibration raises pitch
Voice can break down
• Air pressure system gets hampered. Air flow is inefficient .e.g. asthma, emphysema.
• Vibratory system gets compromises causing hoarseness and voice symptoms eg.cold.