Ptolemismic chords: Difference between revisions

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The ptolemismic triad consists of [[11/8]] and a stack of two [[6/5]]'s closing at the octave:  
The ptolemismic triad consists of [[11/8]] and a stack of two [[6/5]]'s closing at the octave:  
* 1-11/8-5/3 with steps of 11/8-6/5-6/5.  
* 1–11/8–5/3 with steps of 11/8, 6/5, 6/5.  


For tetrads, there are two palindromic chords and two pairs of chords in inverse relationship. The palindromic chords are
For tetrads, there are two palindromic chords and two pairs of chords in inverse relationship. The palindromic chords are
* 1-9/8-5/4-9/5 with steps 9/8-11/10-16/11-11/10;
* 1–9/8–5/4–9/5 with steps 9/8, 11/10, 16/11, 11/10;
* 1-3/2-5/3-9/5 with steps 3/2-11/10-12/11-11/10.
* 1–3/2–5/3–9/5 with steps 3/2, 11/10, 12/11, 11/10.


The inversely related pairs of chords are
The inversely related pairs of chords are
* 1-11/8-3/2-5/3 with steps 11/8-12/11-11/10-6/5, and its inverse
* 1–11/8–3/2–5/3 with steps 11/8, 12/11, 11/10, 6/5, and its inverse
* 1-11/8-5/3-11/6 with steps 11/8-6/5-11/10-12/11;  
* 1–12/11–3/2–9/5 with steps 12/11, 11/8, 6/5, 11/10;  
* 1-5/4-11/8-5/3 with steps 5/4-11/10-6/5-6/5, and its inverse
* 1–5/4–3/2–9/5 with steps 5/4, 6/5, 6/5, 11/10, and its inverse
* 1-11/10-11/8-5/3 with steps 11/10-5/4-6/5-6/5.  
* 1–6/5–3/2–5/3 with steps 6/5, 5/4, 11/10, 6/5.  


For pentads, there are two palindromic chords and a pair of chords in inverse relationship. The palindromic chords are
For pentads, there are two palindromic chords and a pair of chords in inverse relationship. The palindromic chords are
* 1-11/8-3/2-5/3-11/6 with steps 11/8-12/11-11/10-11/10-12/11;
* 1–9/8–5/4–3/2–9/5 with steps 9/8, 11/10, 6/5, 6/5, 11/10;
* 1-9/8-5/4-3/2-9/5 with steps 9/8-11/10-6/5-6/5-11/10.
* 1–11/8–3/2–5/3–11/6 with steps 11/8, 12/11, 11/10, 11/10, 12/11.


The inversely related pair of chords is
The inversely related pair of chords is
* 1-5/4-11/8-3/2-5/3 with steps 5/4-11/10-12/11-11/10-6/5, and its inverse
* 1–5/4–3/2–5/3–9/5 with steps 5/4, 6/5, 11/10, 12/11, 11/10, and its inverse
* 1-11/10-11/8-5/3-11/6 with steps 11/10-5/4-6/5-11/10-12/11.  
* 1–6/5–3/2–5/3–9/5 with steps 6/5, 5/4, 11/10, 12/11, 11/10.  


Equal divisions with ptolemismic chords include [[19edo]], [[22edo]], [[37edo]], [[41edo]] and [[104edo]].
[[Equal temperament]]s with ptolemismic chords include {{EDOs| 19, 22, 37, 41, and 104 }}.


[[Category:11-odd-limit]]
[[Category:11-odd-limit chords]]
[[Category:Essentially tempered chords]]
[[Category:Essentially tempered chords]]
[[Category:Triads]]
[[Category:Triads]]

Latest revision as of 10:23, 10 October 2024

Ptolemismic chords are essentially tempered chords tempered by the ptolemisma, 100/99.

There are one triad, six tetrads and four pentads as 2.3.5.11 subgroup 11-odd-limit essentially tempered chords.

The ptolemismic triad consists of 11/8 and a stack of two 6/5's closing at the octave:

  • 1–11/8–5/3 with steps of 11/8, 6/5, 6/5.

For tetrads, there are two palindromic chords and two pairs of chords in inverse relationship. The palindromic chords are

  • 1–9/8–5/4–9/5 with steps 9/8, 11/10, 16/11, 11/10;
  • 1–3/2–5/3–9/5 with steps 3/2, 11/10, 12/11, 11/10.

The inversely related pairs of chords are

  • 1–11/8–3/2–5/3 with steps 11/8, 12/11, 11/10, 6/5, and its inverse
  • 1–12/11–3/2–9/5 with steps 12/11, 11/8, 6/5, 11/10;
  • 1–5/4–3/2–9/5 with steps 5/4, 6/5, 6/5, 11/10, and its inverse
  • 1–6/5–3/2–5/3 with steps 6/5, 5/4, 11/10, 6/5.

For pentads, there are two palindromic chords and a pair of chords in inverse relationship. The palindromic chords are

  • 1–9/8–5/4–3/2–9/5 with steps 9/8, 11/10, 6/5, 6/5, 11/10;
  • 1–11/8–3/2–5/3–11/6 with steps 11/8, 12/11, 11/10, 11/10, 12/11.

The inversely related pair of chords is

  • 1–5/4–3/2–5/3–9/5 with steps 5/4, 6/5, 11/10, 12/11, 11/10, and its inverse
  • 1–6/5–3/2–5/3–9/5 with steps 6/5, 5/4, 11/10, 12/11, 11/10.

Equal temperaments with ptolemismic chords include 19, 22, 37, 41, and 104.