How Voice Pitch is Produced
Voice pitch describes how high or low a sound is perceived. It directly relates to the frequency of sound waves: higher frequency vibrations result in a higher perceived pitch, while lower frequency vibrations lead to a lower perceived pitch.
Voice pitch production begins in the larynx, commonly known as the voice box, located in the throat. Inside are two bands of muscle and tissue called vocal cords, also referred to as vocal folds. These folds stretch horizontally across the larynx.
When air is expelled from the lungs, it travels up the windpipe and passes through the vocal cords. This causes the vocal cords to vibrate rapidly, generating sound waves.
Faster vocal cord vibrations produce a higher pitch, while slower vibrations result in a lower pitch. For example, a man’s vocal cords might vibrate around 110 cycles per second, a woman’s between 180 to 220 cycles per second, and a child’s around 300 cycles per second.
Muscles within the larynx adjust the tension and length of the vocal cords, changing vibration frequency and pitch. For instance, the cricothyroid (CT) muscles stretch and thin the vocal folds, increasing their tension and leading to higher pitches. This action is similar to tightening a guitar string to produce a higher note.
Conversely, other laryngeal muscles, such as the thyroarytenoid (TA) muscles, can shorten and thicken the vocal folds. This reduces their tension, causing them to vibrate more slowly and produce lower pitches.
Factors Shaping Voice Pitch
Individual voice pitch is influenced by anatomical differences, hormonal changes, and the natural aging process. The length, thickness, and tension of vocal cords, along with larynx size, play a significant role. Longer and thicker vocal cords generally vibrate slower, producing a lower pitch, similar to how thicker strings on a musical instrument create deeper sounds.
Gender significantly shapes voice pitch, primarily due to hormonal changes, particularly during puberty. In males, a surge in testosterone causes the larynx to grow substantially and the vocal cords to lengthen and thicken. This leads to a noticeable drop in voice pitch, often by about an octave, and the development of a more prominent Adam’s apple.
While females also experience laryngeal growth during puberty, the changes are less dramatic compared to males. Estrogen and progesterone influence vocal cord development, leading to a slight deepening of the voice, but without the pronounced pitch drop seen in males.
Voice pitch also changes throughout a person’s life due to the natural aging process. From childhood, vocal cords grow and mature, leading to an initial deepening of the voice. During adolescence, vocal structures undergo rapid development.
As individuals continue to age into their later years, the voice can undergo further alterations, a condition sometimes referred to as presbyphonia. The muscles and tissues in the vocal cords may lose strength and elasticity, and the vocal folds themselves can thin or atrophy. This can lead to changes such as a weaker, breathier voice, reduced vocal range, and shifts in pitch.
In older men, vocal cords may thin and stiffen, sometimes leading to a higher-pitched voice, while older women may experience a slight lowering of pitch. Other influences on voice pitch include individual muscle control, the amount of respiratory support, and certain health conditions, such as Parkinson’s disease, which can alter pitch.