Just Tuning

Just tuning frequencies of all notes in each key based on A = 440 Hz when in the key of C. The just scale ratios of 24:27:30:32:36:40:45 are used and each key note has the same frequency in the scales with +/- 1 sharp or flat. Note that the 6th note in a key changes frequency when it becomes the 2nd of the key with one more sharp or one less flat. The change is upwards by a ratio of 81/80. All other notes retain the same frequency. Note that in C all frequencies are an exact number of Hertz.
   Note   C       Db      D       Eb      E       F       Gb      G       Ab      A       Bb      B
Key

Gb (6b)         278.123         309.026         347.654 370.831         417.185         463.539 494.442
                                                        =======
Db (5b) 260.741 278.123         312.889         347.654 370.831         417.185         463.539
                =======
Ab (4b) 260.741 278.123         312.889         347.654         391.111 417.185         469.333
                                                                        =======
Eb (3b) 260.741         293.333 312.889         352             391.111 417.185         469.333
                                =======
Bb (2b) 264             293.333 312.889         352             391.111         440     469.333
                                                                                        =======
F (1b)  264             293.333         330     352             396             440     469.333
                                                ===
C (0)   264             297             330     352             396             440             495
        ===
G (1#)  264             297             330             371.25  396             445.5           495
                                                                ===
D (2#)          278.438 297             334.125         371.25  396             445.5           495
                        ===
A (3#)          278.438 297             334.125         371.25          417.656 445.5           501.188
                                                                                =====
E (4#)          278.438         313.242 334.125         375.891         417.656 445.5           501.188
                                        =======
B (5#)          281.918         313.242 334.125         375.891         417.656         469.863 501.188
                                                                                                =======
F# (6#)         281.918         313.242         352.397 375.891         422.877         469.863 501.188
                                                        =======

Note    C       C#      D       D#      E       F       F#      G       G#      A       A#      B

E.T.    261.626 277.183 293.665 311.127 329.628 349.228 369.994 391.995 415.305 440.000 466.164 493.883
Incidentals tuning must be worked out on a case by case basis. Often the minor third and minor seventh take the ratios 28 and 42 when the tonic is taken as 24, so that in C the tuning for Eb and Bb would be 308 Hz and 462 Hz. These frequencies allow dominant seventh chords with frequency ratios of 4:5:6:7.

The line labeled "E.T." is the frequencies used for the equitempered scale in which each semitone has a ratio of the 12th root of 2 or 1.0594631.

There is a difference between Gb and F# which amounts to a ratio of (3^12)/(2^19) = 1.0136433 as discovered by Pythagoras.

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