Hemififths

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Hemififths is the temperament tempering out the breedsma, 2401/2400, and the hemifamity comma, 5120/5103, and as the name suggests, uses a neutral third as a generator. Hemif is the no-5 subgroup version of hemififths. It is supported by 41-, 58-, and 99et.

Hemififths was named by Gene Ward Smith in 2004[1].

See Breedsmic temperaments #Hemififths and No-fives_subgroup_temperaments#Hemif for more technical data.

Interval chain

In the following table, odd harmonics 1–21 are labeled in bold.

# Cents* Approximate Ratios ups and downs

notation **

7-limit 13-limit Extension
0 0.0 1/1 P1
1 351.4 49/40, 60/49 11/9, 16/13, 27/22, 39/32 ~3 = ^m3 = vM3
2 702.9 3/2 P5
3 1054.3 90/49 11/6, 24/13 ~7 = ^m7 = vM7
4 205.8 9/8 M2
5 557.2 112/81 11/8, 18/13 ~4 = ^4 = vA4
6 908.7 27/16 22/13 M6
7 60.1 28/27 33/32, 27/26 ^1 = \m2
8 411.6 80/63, 81/64 14/11, 33/26 M3
9 763.0 14/9 ^5 = \m6
10 1114.5 40/21 21/11 M7
11 265.9 7/6 ^M2 = \m3
12 617.4 10/7 A4 = \~5
13 968.8 7/4 ^M6 = \m7
14 120.2 15/14 14/13 A1 = \~2
15 471.7 21/16 ^M3 = \4
16 823.1 45/28 21/13 A5 = \~6
17 1174.6 63/32, 160/81 ^M7 = \8
18 326.0 98/81, 135/112 40/33 A2 = \~3
19 677.5 40/27 ^A4 = \5
20 1028.9 49/27 20/11 A6 = \~7
21 180.4 10/9 ^A1 = \M2
22 531.8 49/36 15/11 A3 = \~4
23 883.3 5/3 ^A5 = \M6
24 34.7 49/48, 50/49 40/39, 45/44, 55/54, 65/64 A7 - P8 = -d2 = ^\1
25 386.2 5/4 ^A2 = \M3
26 737.6 49/32 20/13 AA4 = ^\5
27 1089.1 15/8 ^A6 = \M7
28 240.5 147/128 15/13 AA1= ^\2
29 591.9 45/32 ^A3 = \A4

* In 7-limit CTE tuning, generator = 351.445¢, P5 = 702.89¢, c = 2.89¢

** Enharmonic equivalences: vvA1 and v\m2. Cents: ^1 = 50¢ + 3.5c and /1 = 50¢ - 8.5c

Notation

Hemififths can be notated in neutral chain-of-fifths notation, in which case 5/4 is represented by a sesqui-augmented second (C–DHeQu3.svg), and 7/4 by a semi-augmented sixth (C–AHeQu1.svg). In the 13-limit extension, 11/8 is represented by the semi-augmented fourth (C–FHeQu1.svg), and 13/8 by the neutral sixth (C–AHeQd1.svg). This, of course, defies the tradition of tertian harmony. The just major triad on C is C–DHeQu3.svg–G, for example. One may want to adopt one or more additional modules of accidentals such as arrows or +/- signs to represent the comma steps. There are two notable comma steps:

  1. The syntonic~septimal comma (-17 gensteps, semidiminished second);
  2. The Pythagorean comma (+24 gensteps, inverse diminished second).

Below is tabulated how to notate the prime harmonics with an arrow representing a syntonic~septimal comma (thus ^C = Ddb).

Hemififths nomenclature
for selected intervals
Ratio Nominal Example
3/2 Perfect fifth C–G
5/4 Down major third C–vE
7/4 Down minor seventh C–vBb
11/8 Semi-augmented fourth C–Ft
13/8 Neutral sixth C–Ad

Below is tabulated how to notate the prime harmonics with an arrow representing a Pythagorean comma (thus ^C = B#).

Hemififths nomenclature
for selected intervals
Ratio Nominal Example
3/2 Perfect fifth C–G
5/4 Up neutral third C–^Ed
7/4 Up semidiminished seventh C–^Bdb
11/8 Semi-augmented fourth C–Ft
13/8 Neutral sixth C–Ad

Chords

Scales

Tunings

Tuning spectrum

Edo
generator
Eigenmonzo
(unchanged-interval)
*
Generator (¢) Comments
11/9 347.408
11/6 349.788
7\24 350.000 Lower bound of 7- and 9-odd-limit diamond monotone
11/8 350.264
3/2 350.978
12\41 351.220 Lower bound of 11- to 15-odd-limit
and 13-limit 21-odd-limit diamond monotone
21/16 351.385
15/14 351.389
15/8 351.417
41\140 351.429
7/4 351.448 7-, 9- and 11-odd-limit hemif minimax
5/4 351.453 5-, 7-, 9- and 11-odd-limit minimax
7/5 351.457
25/24 351.472 Very close to argent temperament with neutral intervals (351.47186 cents)
49/48 351.487
5/3 351.494
29\99 351.515
7/6 351.534
9/5 351.543
21/20 351.553
9/7 351.657
15/11 351.680
15/13 351.705 15-odd-limit minimax
17\58 351.724
11/10 351.750
13/10 351.761 13-odd-limit minimax
13/11 351.798 13- and 15-odd-limit hemif minimax
21/13 351.891
21/11 351.946
22\75 352.000
13/7 352.021
11/7 352.188
13/9 352.676
5\17 352.941 Upper bound of 7- to 15-odd-limit
and 13-limit 21-odd-limit diamond monotone
13/12 353.809
13/8 359.472

* Besides the octave

Notes