Most people realize speech and other sounds are created by the use of the vocal cords but do not know how phonation or vocalization actually work. Understanding can give you a more holistic view of singing and improve your tone quality. Ultimately use of your vocal cords makes all the difference to your overall sound.

What is the Larynx? The larynx, often referred to as the voice box, is located on the neck where the Adam’s apple is.

Other than housing and protecting the vocal cords, the larynx also aids in breathing and shielding the windpipe and lungs from foreign objects. There are many muscles housed in the voice box that aid in vocalization, only one being the vocalis muscle, which provides the main mass of the vocal cords. Laryngeal activity is another and possibly more accurate way to refer to vocalization, because it refers to all muscles involved.

Phonation: Phonation is defined as vocalization. Vocal sound is created by the opening and closing of the vocal cords, caused by air flow from the lungs. Muscular resistance to the air pressure also determines sounds from breathy to pressed or pinched.

Bernoulli’s Principle: Bernoulli’s principle explains why air opens and shuts the cords. It is the same principle that keeps airplanes in the air. It states that slower moving air has more air pressure than faster moving air. When the space between the vocal cords is narrow, it is similar to a spot on the freeway that goes from four lanes to one.

Before the constricted area, cars build up and slow down. During the one lane opening, few cars slowly get through and speed up after the highway opens up to four lanes again. The same goes for air flow through the vocal cords; pressure builds up below the vocal cords when the space between them is narrow. Eventually increased air pressure bursts them open. Some muscular resistance to Bernoulli’s principle manipulates sound produced by laryngeal activity.

Examples of Action of Vocal Cords: Take two sheets of paper and place them vertically in front of your mouth. Blow air forcefully through them. You might think the air will push the papers apart. It actually causes the papers to flap together, which is a very clear representation of how the vocal cords work inside the larynx. Another similar activity is to buzz the lips, by keeping them loose and the breath flowing. If you add pitch to the buzz, notice the lips elongate and loosen on lower notes and shorten and tighten on higher ones.

Resonating Chambers: Notice the two vibrating papers make very little sound. Vocalization, however, makes a significantly louder sound because of the resonating chamber of the vocal tract in the human body. Each vocal cycle creates a puff of air produced by the subglottic pressure caused by Bernoulli’s Principle as the vocal cords suddenly open. Each air puff is like a tap on a drum. It sends a wave down the vocal tract causing it to vibrate. The rate at which the vocal tract vibrates determines pitch. So, 440 puffs of air per second create the pitch A above middle C. The frequency is referred to as 440Hz or hertz, which means cycles per second. The vocal tract can also be adjusted to create a louder or quieter sound.

Breath Threshold: The perfect balance between air energy and muscular resistance to air pressure, creating the loudest, most efficient sound without causing tension. If you sound “breathy,” you may be letting too much air out all at once or you may not be using your vocal cords efficiently.