Introductory examples in Sagittal notation: Difference between revisions
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This page lists a few elementary examples that hopefully shed some light on the philosophy (and the pitfalls!) of [[Sagittal_notation|Sagittal notation]]. For a detailed introduction into Sagittal notation the document [[:File:Sagittal.pdf|Sagittal.pdf]] is the reference. | This page lists a few elementary examples that hopefully shed some light on the philosophy (and the pitfalls!) of [[Sagittal_notation|Sagittal notation]]. For a detailed introduction into Sagittal notation the document [[:File:Sagittal.pdf|Sagittal.pdf]] is the reference. | ||
=Just intonation: notating | =Just intonation: notating a harmonic scale= | ||
As the introduction [[:File:Sagittal.pdf|Sagittal.pdf]] says, Sagittal notation uses a conventional staff on which the natural notes are in a single series of fifths, i.e, in the case of just intonation, in [[3-limit|Pythagorean tuning]]. The meaning of conventional sharps and flats is Pythagorean as well, i.e. they stand for raising the corresponding note by a [[2187/2048|Pythagorean chromatic semitone (apotome)]], a "large" semitone 113.7 cents in size. | As the introduction [[:File:Sagittal.pdf|Sagittal.pdf]] says, Sagittal notation uses a conventional staff on which the natural notes are in a single series of fifths, i.e, in the case of just intonation, in [[3-limit|Pythagorean tuning]]. The meaning of conventional sharps and flats is Pythagorean as well, i.e. they stand for raising the corresponding note by a [[2187/2048|Pythagorean chromatic semitone (apotome)]], a "large" semitone 113.7 cents in size. | ||
For the notation of notes in higher [[Harmonic_Limit|limits]], additional symbols are introduced. The intervals these symbols stand for are mostly [[Comma|commas]] - the maybe most elementary example is the [[81/80|syntonic comma]] (ratio 81/80, 21.506 cents), the difference between a pythagorean and a just major third, necessary for just intonation in [[5-limit|5-limit]]. Other elementary commas appearing along the | For the notation of notes in higher [[Harmonic_Limit|limits]], additional symbols are introduced. The intervals these symbols stand for are mostly [[Comma|commas]] - the maybe most elementary example is the [[81/80|syntonic comma]] (ratio 81/80, 21.506 cents), the difference between a pythagorean and a just major third, necessary for just intonation in [[5-limit|5-limit]]. Other elementary commas appearing along the harmonic series are: in [[7-limit|7-limit]] the [[64/63|septimal comma or Architas' comma]] (64/63, 27.264 Cents), the difference between a minor and a harmonic seventh, and, in [[11-limit|11-limit]], the [[33/32|undecimal comma or al-Farabi quarter-tone]] (33/32, 53.2729 cents), the difference between an undecimal semi-augmented and a perfect fourth. | ||
With the Sagittal symbos for these three commas, a scale consisting of the | With the Sagittal symbos for these three commas, a scale consisting of the harmonics 4 to 11 can be written as follows: | ||
[[File:SagittalOvertoneSeries.jpg|alt=SagittalOvertoneSeries.jpg|SagittalOvertoneSeries.jpg]] | [[File:SagittalOvertoneSeries.jpg|alt=SagittalOvertoneSeries.jpg|SagittalOvertoneSeries.jpg]] | ||
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[[File:SagittalEDOExample.jpg|alt=SagittalEDOExample.jpg|SagittalEDOExample.jpg]] | [[File:SagittalEDOExample.jpg|alt=SagittalEDOExample.jpg|SagittalEDOExample.jpg]] | ||
What is displayed is the tetrad consisting of the | What is displayed is the tetrad consisting of the harmonics 4 to 7 (respectively, in equal temperaments, of their approximations), a chord resembling a dominant seventh chord. It appears first in mixed Sagittal notation for just intonation, with the syntonic comma symbol at the E note and the septimal comma symbol at the Bb note. | ||
In equal temperaments, we could, in theory, write it always like that, following guideline 1. But depending on the concrete equal division there will be harmonic equivalences that suggest certain simplifications. | In equal temperaments, we could, in theory, write it always like that, following guideline 1. But depending on the concrete equal division there will be harmonic equivalences that suggest certain simplifications. | ||