Acoustics & Music Theory
why it sounds like that
Generator

The same total, distributed differently

The departure of each of the twelve major thirds from a pure 5:4, one row per temperament, keys ordered round the circle of fifths. The totals are equal — every closing temperament's twelve thirds add to 4800 cents — so what a temperament chooses is not how much error there is but which keys carry it.
The same total, distributed differently. The departure of each of the twelve major thirds from a pure 5:4, one row per temperament, keys ordered round the circle of fifths. The totals are equal — every closing temperament's twelve thirds add to 4800 cents — so what a temperament chooses is not how much error there is but which keys carry it.

Drawn above with its standard settings, which is almost never how an essay draws it: an essay states the numbers it is arguing about, so the figure a reader meets there is about that argument rather than about the drawing in general. Every option a placement passes is checked against the ones this function actually reads, because an option it does not read is silently ignored and the figure quietly draws what is above instead.

It makes a noise. 8 of its 8 placements carry sound, built from the same numbers as the drawing, offering these buttons: C major third, Werckmeister III, C major third, equal, F♯ major third, Werckmeister III, The major third on C in Pythagorean: 407.8 cents, against the pure 386.3, The major third on C in equal temperament: 400.0 cents, against the pure 386.3.

Called by 3 essays

the blast radius of changing it

The same total, distributed differently. The departure of each of the twelve major thirds from a pure 5:4, one row per temperament, keys ordered round the circle of fifths. The totals are equal — every closing temperament's twelve thirds add to 4800 cents — so what a temperament chooses is not how much error there is but which keys carry it.

What a temperament cannot do

Add up the twelve major thirds of any keyboard tuning whose chain of fifths closes and the answer is 4,800 cents. Every time, in every system, before a single fifth has been chosen. So no temperament has ever made the average third less wrong than any other one, and four hundred years of argument were about a distribution rather than about accuracy.

tuning · The comma How far out of tune an interval has to be before its beat is usable. An earlier essay produced a modulation index for every interval on a stated timbre; whether a fluctuation of that index at that rate can be detected is a published function of both. Running one against the other turns a table of decibels into a window in cents. The bar is the mistuning over which the beat is both deep enough to notice and at a rate a tuner can use — not so slow that a beat takes half a minute to complete, not so fast that it has stopped being a beat. the major third gives the widest window, 1.3 to 60.0 cents, and the minor sixth the narrowest, 0.8 to 38.9. The ordering is the opposite of the dip's: the octave has the shallowest dip on a string spectrum and the widest usable window, because its coincidence sits at a low partial and a given mistuning therefore produces a slower beat. Depth and rate pull opposite ways, and it is the rate that decides.

The beat a tuner can actually use

There is a modulation index for every interval on every timbre, and the published threshold for detecting a fluctuation is a function of exactly that and its rate. Running one against the other turns a table of decibels into a window in cents — and reverses the ordering, because the interval with the shallowest dip has the widest window.

intervals · Beating Four of the five are a whole number of semitones, and one is exactly half of one. Each mismatch in cents, against the ticks at whole semitones — which are the only places a transposing keyboard can put a player. 4 of the 5 land within six cents of a tick: the Chorton–Kammerton gap is 197 cents against a whole tone's 200, and Chorton against French pitch is 296 against a minor third's 300. The exception is an English organ against Handel's fork, at 50 cents — 50 cents from the nearest tick, which is as far as it is possible to be. So the small mismatches are the unsolvable ones, and the large ones were solved by shifting the keys.

The instrument that cannot be moved

A string is regauged and a woodwind is scaled. An organ's pitch is the length of its pipes, and metal can be cut off and cannot be put back — so an organ is a ratchet that only goes sharp. The mechanical answer was to shift the keyboard against the pipes, and its cost is not the transposition. It is that the temperament's key colours rotate out from under the notation, by an amount measured in fifths rather than in semitones.

tuning · Pitch standard

All figures · What can be heard