Starling chords

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Starling chords are essentially tempered dyadic chords tempered by the starling comma, 126/125.

The starling tetrad is an 126/125-tempered chord which in close position (reduced to an octave) consists of a chain of three approximate 6/5 minor thirds and an approximate 7/6 subminor third, in a tuning which tempers out the starling comma, 126/125, and hence causes it to close on the octave. That is, it is a starling-tempered 6/5-6/5-6/5-7/6, which may also be regarded as a tempered 1-6/5-10/7-12/7; it is also known as the septimal semicomma diminished seventh chord. In a meantone tuning the starling tetrad is three minor thirds and an augmented second, which is the traditional diminished seventh chord of common practice music in the meantone era.

Also familiar from the music of common practice is the diminished triad, a tempering of 1-6/5-10/7 with steps 6/5-6/5-7/5 when understood septimally. Other essentially tempered starling triads are the 1-5/4-7/5 chord with steps 5/4-10/9-10/7 and its inversion, 1-5/4-9/5 with steps 5/4-10/7-10/9.

For starling tetrads, we also have the 1-5/4-3/2-9/5 chord with steps 5/4-6/5-6/5-10/9 and its inversion, 1-6/5-3/2-5/3; the 1-5/4-7/5-7/4 chord with steps of 5/4-10/9-5/4-8/7; the 1-5/4-7/5-9/5 chord with steps of 5/4-10/9-9/7-10/9; and the 1-9/8-5/4-9/5 chord with steps of 9/8-10/9-10/7-10/9.

There is also a unique starling pentad, 1-9/8-5/4-3/2-9/5, with steps of 9/8-10/9-6/5-6/5-10/9, a modified complete ninth chord. In the transposition 1-6/5-4/3-3/2-5/3 with steps 6/5-10/9-9/8-10/9-6/5 we can more easily see that the steps are symmetrical around 9/8.

Starling chords come to triads: 3, tetrads: 6, pentads: 1, for a total of 10.

Equal temperaments with starling chords include 19, 27, 31, 43, 46, 50, 58, 77, 185 and 265c, and using the patent val tuning, 34 and 65.