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Scale 1621: "Scriabin's Prometheus"

The Prometheus Scale is a collapsed rendition of the Prometheus chord, also known as the "Mystic Chord", made famous by the composer Alexander Scriabin (1871 - 1915). The chord is usually constructed in an open voicing of stacked perfect and altered fourths, but here all those notes are collapsed into one octave. This scale also comes in a variety named Prometheus Neapolitan, which is the same scale but with a lowered second.

Bracelet Diagram

The bracelet shows tones that are in this scale, starting from the top (12 o'clock), going clockwise in ascending semitones. The "i" icon marks imperfect tones that do not have a tone a fifth above. Dotted lines indicate axes of symmetry.

Tonnetz Diagram

Tonnetz diagrams are popular in Neo-Riemannian theory. Notes are arranged in a lattice where perfect 5th intervals are from left to right, major third are northeast, and major 6th intervals are northwest. Other directions are inverse of their opposite. This diagram helps to visualize common triads (they're triangles) and circle-of-fifth relationships (horizontal lines).

Common Names

Named After Composers: Scriabin's Prometheus; Mystic

Carnatic: Raga Barbara

Zeitler: Aeolathimic

Dozenal: Kahian

Analysis

Cardinality Cardinality is the count of how many pitches are in the scale.	6 (hexatonic)
Pitch Class Set The tones in this scale, expressed as numbers from 0 to 11	{0,2,4,6,9,10}
Forte Number A code assigned by theorist Allen Forte, for this pitch class set and all of its transpositional (rotation) and inversional (reflection) transformations.	6-34
Rotational Symmetry Some scales have rotational symmetry, sometimes known as "limited transposition". If there are any rotational symmetries, these are the intervals of periodicity.	none
Reflection Axes If a scale has an axis of reflective symmetry, then it can transform into itself by inversion. It also implies that the scale has Ridge Tones. Notably an axis of reflection can occur directly on a tone or half way between two tones.	none
Palindromicity A palindromic scale has the same pattern of intervals both ascending and descending.	no
Chirality A chiral scale can not be transformed into its inverse by rotation. If a scale is chiral, then it has an enantiomorph.	yes enantiomorph: 1357
Hemitonia A hemitone is two tones separated by a semitone interval. Hemitonia describes how many such hemitones exist.	1 (unhemitonic)
Cohemitonia A cohemitone is an instance of two adjacent hemitones. Cohemitonia describes how many such cohemitones exist.	0 (ancohemitonic)
Imperfections An imperfection is a tone which does not have a perfect fifth above it in the scale. This value is the quantity of imperfections in this scale.	4
Modes Modes are the rotational transformations of this scale. This number does not include the scale itself, so the number is usually one less than its cardinality; unless there are rotational symmetries then there are even fewer modes.	5
Prime Form Describes if this scale is in prime form, using the Rahn/Ring formula.	no prime: 683
Generator Indicates if the scale can be constructed using a generator, and an origin.	none
Deep Scale A deep scale is one where the interval vector has 6 different digits.	no
Interval Structure Defines the scale as the sequence of intervals between one tone and the next.	[2, 2, 2, 3, 1, 2]
Interval Vector Describes the intervallic content of the scale, read from left to right as the number of occurences of each interval size from semitone, up to six semitones.	<1, 4, 2, 4, 2, 2>
Interval Spectrum The same as the Interval Vector, but expressed in a syntax used by Howard Hanson.	p²m⁴n²s⁴dt²
Distribution Spectra Describes the specific interval sizes that exist for each generic interval size. Each generic <g> has a spectrum {n,...}. The Spectrum Width is the difference between the highest and lowest values in each spectrum.	<1> = {1,2,3} <2> = {3,4,5} <3> = {5,6,7} <4> = {7,8,9} <5> = {9,10,11}
Spectra Variation Determined by the Distribution Spectra; this is the sum of all spectrum widths divided by the scale cardinality.	1.667
Maximally Even A scale is maximally even if the tones are optimally spaced apart from each other.	no
Maximal Area Set A scale is a maximal area set if a polygon described by vertices dodecimetrically placed around a circle produces the maximal interior area for scales of the same cardinality. All maximally even sets have maximal area, but not all maximal area sets are maximally even.	no
Interior Area Area of the polygon described by vertices placed for each tone of the scale dodecimetrically around a unit circle, ie a circle with radius of 1.	2.482
Polygon Perimeter Perimeter of the polygon described by vertices placed for each tone of the scale dodecimetrically around a unit circle.	5.932
Myhill Property A scale has Myhill Property if the Interval Spectra has exactly two specific intervals for every generic interval.	no
Balanced A scale is balanced if the distribution of its tones would satisfy the "centrifuge problem", ie are placed such that it would balance on its centre point.	no
Ridge Tones Ridge Tones are those that appear in all transpositions of a scale upon the members of that scale. Ridge Tones correspond directly with axes of reflective symmetry.	none
Propriety Also known as Rothenberg Propriety, named after its inventor. Propriety describes whether every specific interval is uniquely mapped to a generic interval. A scale is either "Proper", "Strictly Proper", or "Improper".	Proper
Heteromorphic Profile Defined by Norman Carey (2002), the heteromorphic profile is an ordered triple of (c, a, d) where c is the number of contradictions, a is the number of ambiguities, and d is the number of differences. When c is zero, the scale is Proper. When a is also zero, the scale is Strictly Proper.	(0, 4, 45)

Common Triads

These are the common triads (major, minor, augmented and diminished) that you can create from members of this scale.

* Pitches are shown with C as the root

Triad Type	Triad^*	Pitch Classes	Degree	Eccentricity	Closeness Centrality
Major Triads	D	{2,6,9}	2	2	1
Minor Triads	am	{9,0,4}	1	3	1.5
Augmented Triads	D+	{2,6,10}	1	3	1.5
Diminished Triads	f♯°	{6,9,0}	2	2	1

Above is a graph showing opportunities for parsimonious voice leading between triads^*. Each line connects two triads that have two common tones, while the third tone changes by one generic scale step.

Diameter	3
Radius	2
Self-Centered	no
Central Vertices	D, f♯°
Peripheral Vertices	D+, am

Triad Polychords

Also known as Bi-Triadic Hexatonics (a term coined by mDecks), and related to Generic Modality Compression (a method for guitar by Mick Goodrick and Tim Miller), these are two common triads that when combined use all the tones in this scale.

There is 1 way that this hexatonic scale can be split into two common triads.

Augmented: {2, 6, 10}
Minor: {9, 0, 4}

Modes

Modes are the rotational transformation of this scale. Scale 1621 can be rotated to make 5 other scales. The 1st mode is itself.

2nd mode: Scale 1429	Bythimic
3rd mode: Scale 1381	Padimic
4th mode: Scale 1369	Boptimic
5th mode: Scale 683	Stogimic	This is the prime mode
6th mode: Scale 2389	Eskimo Hexatonic 2

Prime

The prime form of this scale is Scale 683

Scale 683

Stogimic

Complement

The hexatonic modal family [1621, 1429, 1381, 1369, 683, 2389] (Forte: 6-34) is the complement of the hexatonic modal family [683, 1369, 1381, 1429, 1621, 2389] (Forte: 6-34)

Inverse

The inverse of a scale is a reflection using the root as its axis. The inverse of 1621 is 1357

Scale 1357

Takemitsu Linea Mode 2

Enantiomorph

Only scales that are chiral will have an enantiomorph. Scale 1621 is chiral, and its enantiomorph is scale 1357

Scale 1357

Takemitsu Linea Mode 2

Transformations:

In the abbreviation, the subscript number after "T" is the number of semitones of tranposition, "M" means the pitch class is multiplied by 5, and "I" means the result is inverted. Operation is an identical way to express the same thing; the syntax is <a,b> where each tone of the set x is transformed by the equation y = ax + b

Abbrev	Operation	Result	Abbrev	Operation	Result
T₀	<1,0>	1621	T₀I	<11,0>	1357
T₁	<1,1>	3242	T₁I	<11,1>	2714
T₂	<1,2>	2389	T₂I	<11,2>	1333
T₃	<1,3>	683	T₃I	<11,3>	2666
T₄	<1,4>	1366	T₄I	<11,4>	1237
T₅	<1,5>	2732	T₅I	<11,5>	2474
T₆	<1,6>	1369	T₆I	<11,6>	853
T₇	<1,7>	2738	T₇I	<11,7>	1706
T₈	<1,8>	1381	T₈I	<11,8>	3412
T₉	<1,9>	2762	T₉I	<11,9>	2729
T₁₀	<1,10>	1429	T₁₀I	<11,10>	1363
T₁₁	<1,11>	2858	T₁₁I	<11,11>	2726
Abbrev	Operation	Result	Abbrev	Operation	Result
T₀M	<5,0>	1861	T₀MI	<7,0>	1117
T₁M	<5,1>	3722	T₁MI	<7,1>	2234
T₂M	<5,2>	3349	T₂MI	<7,2>	373
T₃M	<5,3>	2603	T₃MI	<7,3>	746
T₄M	<5,4>	1111	T₄MI	<7,4>	1492
T₅M	<5,5>	2222	T₅MI	<7,5>	2984
T₆M	<5,6>	349	T₆MI	<7,6>	1873
T₇M	<5,7>	698	T₇MI	<7,7>	3746
T₈M	<5,8>	1396	T₈MI	<7,8>	3397
T₉M	<5,9>	2792	T₉MI	<7,9>	2699
T₁₀M	<5,10>	1489	T₁₀MI	<7,10>	1303
T₁₁M	<5,11>	2978	T₁₁MI	<7,11>	2606

The transformations that map this set to itself are: T₀

Nearby Scales:

These are other scales that are similar to this one, created by adding a tone, removing a tone, or moving one note up or down a semitone.

Scale 1623				Lothian
Scale 1617				Phronitonic
Scale 1619				Prometheus Neapolitan
Scale 1625				Lythimic
Scale 1629				Synian
Scale 1605				Zanitonic
Scale 1613				Thylimic
Scale 1637				Syptimic
Scale 1653				Minor Romani Inverse
Scale 1557				Jovian
Scale 1589				Raga Rageshri
Scale 1685				Zeracrimic
Scale 1749				Acoustic
Scale 1877				Aeroptian
Scale 1109				Kataditonic
Scale 1365				Whole Tone
Scale 597				Kung
Scale 2645				Raga Mruganandana
Scale 3669				Mothian

This scale analysis was created by Ian Ring, Canadian Composer of works for Piano, and total music theory nerd. Scale notation generated by VexFlow, graph visualization by Graphviz, and MIDI playback by MIDI.js. All other diagrams and visualizations are © Ian Ring. Some scale names used on this and other pages are ©2005 William Zeitler (http://allthescales.org) used with permission.

Pitch spelling algorithm employed here is adapted from a method by Uzay Bora, Baris Tekin Tezel, and Alper Vahaplar. (An algorithm for spelling the pitches of any musical scale) Contact authors Patent owner: Dokuz Eylül University, Used with Permission. Contact TTO

Tons of background resources contributed to the production of this summary; for a list of these peruse this Bibliography. Special thanks to Richard Repp for helping with technical accuracy, and George Howlett for assistance with the Carnatic ragas.