Sensamagic chords

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A sensamagic chord is an essentially tempered dyadic chord tempered by the sensamagic comma, 245/243.

The sensamagic triad is a sensamagic chord with three notes when reduced to the octave. One of the sensamagic triads in close position consists of two supermajor thirds, approximately 9/7, and a minor third, approximately 6/5, which closes at the octave because the sensamagic comma, 245/243, is tempered out:

  • 1-9/7-5/3 with steps of 9/7-9/7-6/5.
sensamagic.jpg
Sensamagic triad

The other sensamagic triads are

  • 1-7/6-9/7, with steps 7/6-10/9-14/9, and its inversion
  • 1-7/6-9/5, with steps 7/6-14/9-10/9.

For sensamagic tetrads there are the following palindromes:

  • 1-7/6-9/7-3/2, with steps 7/6-10/9-7/6-4/3;
  • 1-7/6-9/7-9/5 with steps 7/6-10/9-7/5-10/9.

And the following inversely related pairs:

  • 1-7/6-3/2-9/5 with steps 7/6-9/7-6/5-10/9 and its inversion
  • 1-9/7-3/2-5/3 with steps 9/7-7/6-10/9-6/5;
  • 1-7/6-7/5-9/5 with steps 7/6-6/5-9/7-10/9 and its inversion
  • 1-7/6-9/7-5/3 with steps 7/6-10/9-9/7-6/5.

For pentads there are

  • 1-7/6-9/7-3/2-5/3 with steps 7/6-10/9-7/6-10/9-6/5 and its inversion,
  • 1-7/6-9/7-3/2-9/5 with steps 7/6-10/9-7/6-6/5-10/9.

The 9-odd-limit sensamagic chords are of pattern 1a, meaning that there are 3 triads, 6 tetrads and 2 pentads, for a total of 11 distinct chord structures.

Equal temperaments with sensamagic chords include 19, 22, 27, 41, 46, 65, 68, 87, 128, 196, 283, with 283edo giving the optimal patent val.

See also