Sensamagic

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Sensamagic
Subgroups 2.3.5.7, 2.3.5.7.11
Comma basis 245/243 (7-limit);
245/243, 385/384 (11-limit)
Reduced mapping ⟨1; 1 1 2 -2; 0 2 -1 -1]
ET join 19 & 22 & 24
Generators (CWE) ~3/2 = 703.8 ¢, ~9/7 = 440.9 ¢
MOS scales n/a
Ploidacot n/a
Minimax error 9-odd-limit: 4.73 ¢;
11-limit 21-odd-limit: 5.11 ¢
Target scale size 9-odd-limit: ? notes;
11-limit 21-odd-limit: ? notes

Sensamagic is a rank-3 temperament with the same lattice structure as the 2.3.7 subgroup, while identifying the 5/3 major sixth as a stack of two 9/7 supermajor thirds, tempering out 245/243. It is the head of the sensamagic family.

It favors a sharp supermajor third, and subtracting such a third from a perfect fourth produces a narrow subminor second of 28/27~36/35. The canonical 11-limit extension identifies this interval with 33/32, so that 11/8 is that plus a perfect fourth. This adds 385/384 and 896/891 to the comma list and makes it a member of both keenanismic temperaments and pentacircle clan.

The temperament was named after the corresponding comma, which was named by Gene Ward Smith in 2010. See 245/243 #Etymology.

See Sensamagic family #Sensamagic for technical data.

Interval lattice

Notation

Sensamagic can be notated the same as 2.3.7 just intonation since they share the same lattice structure. One way to do this is to take the conventional circle-of-fifths notation with an additional module of accidentals for the 64/63 comma. In this system, 7/4 is a minor seventh, 5/4 an augmented second, and 11/8 a diminished fifth.

Sensamagic nomenclature
for selected intervals
Ratio Nominal Example
3/2 Perfect 5th C-G
5/4 Double-up augmented 2nd C-^^D#
7/4 Down minor 7th C-vBb
11/8 Down diminished 5th C-vGb

Alternatively, it can be notated the same as full prime-limit just intonation, with a distinct accidental module for each prime harmonic. That makes some intervals more intuitive, at the cost of hiding the structure of sensamagic tempering. For example, it is customary of the 5/4 to be a major third, and 7/4 to be a minor seventh. As a result, the fact that the 5/3 is a stack of two 9/7's is not revealed, and the related chords can be less convenient.

Chords and harmony

Sensamagic enables essentially tempered chords of sensamagic, keenanismic, pentacircle, and undecimal sensamagic.

The sensamagic dominant chord is a dominant seventh chord useful for tonal harmony in this temperament.

Tunings

7-limit norm-based tunings
Euclidean
Constrained Constrained & skewed Destretched
Tenney CTE: ~3/2 = 703.7424 ¢, ~9/7 = 440.9020 ¢ CWE: ~3/2 = 703.7411 ¢, ~9/7 = 440.9017 ¢ POTE: ~3/2 = 703.7424 ¢, ~9/7 = 440.9020 ¢
11-limit norm-based tunings
Euclidean
Constrained Constrained & skewed Destretched
Tenney CTE: ~3/2 = 703.7737 ¢, ~9/7 = 440.9186 ¢ CWE: ~3/2 = 703.7948 ¢, ~9/7 = 440.9180 ¢ POTE: ~3/2 = 703.8004 ¢, ~9/7 = 440.9178 ¢

Tuning spectrum

Todo: complete section