Ptolemismic chords: Difference between revisions

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The '''ptolemismic triad''' is an [[essentially tempered chord]] which is the [[100/99]] tempering of 1-[[11/8]]-[[5/3]], with steps of 11/8-[[6/5]]-6/5. Equal divisions with ptolemismic triads include [[19edo]], [[22edo]], [[37edo]], [[41edo]] and [[104edo]].
'''Ptolemismic chords''' are [[essentially tempered chord]]s tempered by the ptolemisma, [[100/99]].  


[[Category:11-odd-limit]]
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 temperament]]s with ptolemismic chords include {{EDOs| 19, 22, 37, 41, and 104 }}.
 
[[Category:11-odd-limit chords]]
[[Category:Essentially tempered chords]]
[[Category:Triads]]
[[Category:Tetrads]]
[[Category:Pentads]]
[[Category:Ptolemismic]]
[[Category:Ptolemismic]]
[[Category:Essentially tempered chords]]
[[Category:Triad]]

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.