Indiana University

Piano Technology

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Syntonic Comma

What is the Syntonic Comma?

Start with C and tune 4 perfect 5ths to E.
Start from the same C and tune 2 octaves and a pure 3rd to E.
The two Es are not the same.


A perfect 5th is 702 cents

702+702+702+702=2808 cents

An octave is 1200 cents and a pure 3rd is 386 cents

1200+1200+386=2786 cents

2808 - 2786 = 22 cents = Syntonic Comma