Cords in action

So what is actually happening when you sing a song or whisper to a friend?

Well, it's a matter of vibrations. Frequency is how we measure vibrations, traditionally in Hertz (vibrations per second). This frequency can change depending on air pressure, muscle tension, and cord size.

Vocal folds play the part of a reed within the throat by opening and closing, letting more or less air through and vibrating as a product. This process is called phonation. The arytenoid cartilages have a tendency to pivot depending on how much air is being forced through them, otherwise the folds remain closed as a result of the Bernoulli effect. As air pressure increases, frequency increases.

Vocal folds also play the part of guitar strings, varying in size and tension. They are very elastic in nature and certain muscles in the larynx (voice box) have the ability to change the tension of our vocal folds. As size increases, frequency decreases and as tension increases, frequency increases.