Acoustics & Music Theory
why it sounds like that
Concept

Laryngeal mechanism — where it appears

One of the two ways the vocal folds can vibrate — thick and fully closing, or thin and stretched — which a singer changes between at a definite pitch. The change is of mechanism rather than of effort, which is why the register break sits at a frequency and does not move when the pitch standard does.

Named by 2 essays across 2 fields — each of them below, with the objects they name alongside it.

Two mechanisms, the notes both of them make, and the seam. The frequency range of each laryngeal mechanism for an adult male voice, on a logarithmic axis, with the band both can produce shaded. M1 — chest runs 82–349 Hz and M2 — falsetto runs 220–698 Hz, so 799 cents of the range — 8.0 semitones — can be sung either way. The two dots inside that band are the measured signature that this is a bifurcation rather than a threshold: the change upward happens at 330 Hz and the change downward at 294 Hz, 200 cents lower. A threshold is crossed at the same place in both directions and this is not.

Two mechanisms, and the seam between them

Every singer has a place in the range where the voice changes character, and eight semitones of it can be produced either way. The measurement that settles what kind of a place it is takes ten seconds: the change upward happens two hundred cents higher than the change downward, and a threshold cannot do that.

instruments · The voice Where the register break falls on a tenor's page. The two measured laryngeal crossings — 330 hertz going up and 294 coming down — read as WRITTEN notes, against the pitch standard the part is performed at. The crossings are frequencies and do not move; the notation does, so the seam slides down the stave by exactly the interval the standard rises. At A392 the upward crossing is written F♯4, at A415 it is F4, at A440 E4 and at A465 E♭4 — a minor third of movement across four centuries, on a part nobody rewrote. Across the range drawn the seam passes 4 written semitones. The shaded horizontal band is the tenor's written compass, C3 to A4; the seam is inside it at 7 of the 7 documented standards drawn.

A standard moves the page, and not the seam

Every earlier essay has priced a pitch standard against something with a fixed length in it. A voice has none, so nothing about it changes at all — what changes is where the written note falls against a break in the larynx that is a frequency and stays put. At A415 that break is written F4, at A440 it is E4 and at Chorton it is E♭4: a minor third of movement across four centuries, on a part nobody rewrote.

tuning · Pitch standard

Named alongside it

The objects these essays reach for when they reach for this one.

RegisterBoundary conditionCentsGlottisIntonationNonlinearityOpen quotientOverblowingPitch standardSpectrumTessituraTransposition

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