Singing Voice

The two folds in cross-section, each two masses on springs (the lower and the upper edge), as a stroboscope shows them: one cycle of C4, slowed to a second and a half. Air from the lungs below pushes them apart from the bottom up; they snap shut from the bottom up too, the upper edge lagging. Below, the flow of air through them over the same cycle: a pulse each time they open, cut off sharply as they shut, which is where the voice's harmonics come from.

The tube from the folds (left) to the lips (right), as wide as it is at each point: the larynx tube, the throat, the mouth. Its shape is the vowel: the mod wheel moves it from oo to ee. Below, how strongly it passes each frequency: its peaks are the formants, marked, and the note's harmonics are the ticks under them.

Every note is a stack of harmonics, the formants the bands where they are loudest. Sweep the vowel and the bands move while the harmonics stay; sing a scale on one vowel and the harmonics move under bands that stay. The vibrato waves every harmonic, the high ones the most.

Each vowel as its first two formants, on axes that run the way phoneticians draw them, so the chart is a map of the mouth: front vowels left, back ones right, open ones low. The grey letters are Peterson and Barney's averages for men (1952); the line is where the mod wheel goes; the dot is the tract now, after its length and the jaw.