The human voice is classified into various types, based on pitch, timbre, and various other factors that influence our perception of someone’s voice, or how that voice can be used. In this tutorial, we’ll explain some of the physiological factors that influence the pitch and timbre of our voices.

Is it body size?
The most obvious influence on pitch that comes to mind is the size of the sound-producing apparatus; we can observe from the instruments of the orchestra that smaller objects tend to make higher-pitched sounds, and larger ones produce lower-pitched sounds. So it’s logical to assume that small people would make high sounds, and large people would make low sounds. And this assumption is borne out by the facts, at least to an extent. Baby cries have a fundamental frequency (hereafter referred to as Fo) of around 500 Hz (roughly corresponding to the note B4). Child speech ranges from 250-400 Hz (notes B3 to G4, adult females tend to speak at around 200 Hz on average (about G3), and adult males around 125 Hz (or, B2).

So, it does seem to make sense to relate body size to Fo, at least at first. But if we think more about it, we know that big opera singers don’t always make low sounds; there are very large sopranos, and some rather short, slender basses. So body weight and height can’t be a sole determining factor.

Is it laryngeal size?
Perhaps a measurement of something more relevant to the voice source itself, such as the size of the larynx, would be more helpful. Men, on average, have a larynx which is about 40% taller and longer (measured along the axis of the vocal folds) than women, as seen below. But this does not explain all of the difference between male and female Fo. But there is a size difference inside the larynx which explains the full difference…