Neutral second: Difference between revisions

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'''Neutral seconds''' are intervals with a size in between a whole tone and a semitone. They are one of the most distinctive-sounding yet versatile xenharmonic intervals, which makes them highly valuable.
 
 
A '''neutral second''', as a concrete interval region, is typically near 150 cents in size, distinct from [[Semitone|semitones]] of roughly 100 cents and [[Major second|major seconds]] of roughly 200 cents. A rough tuning range of the neutral second is 130 to 170 cents, and they characteristically are half of some kind of [[minor third]]. Neutral seconds are not found in diatonic, but they do exist in a diatonic functional context as "neutral" diatonic intervals.
 
They are one of the most distinctive-sounding yet versatile xenharmonic intervals, which makes them highly valuable.


==Function==
==Function==
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In larger edos, it's possible to have a similar tuning of intervals, but without Porcupine tempering. In the 100b val, the T10/9 is a slightly larger 168¢ in exchange for making the T81/80 48¢, a much more usable aberrisma than Porcupine typically offers.
In larger edos, it's possible to have a similar tuning of intervals, but without Porcupine tempering. In the 100b val, the T10/9 is a slightly larger 168¢ in exchange for making the T81/80 48¢, a much more usable aberrisma than Porcupine typically offers.
== In just intonation ==
=== By prime limit ===
The [[Pythagorean tuning|3-limit]] does not have a simple neutral second, so we start with the 5-limit:
* The 5-limit '''acute minor second''' or '''large limma''' is a ratio of [[27/25]], and is about 133{{c}}.
* The 7-limit neutral second is a ratio of [[35/32]], and is about 155{{c}}.
** There is also a 7-limit '''swetismic neutral second''', which is a ratio of [[49/45]], and is about 147{{c}}.
* The 11-limit neutral/submajor seconds are the ratios of [[12/11]] and [[11/10]], which are about 151{{c}} and 165{{c}}, respectively; 11/10 in particular can also be analyzed as a [[major second]]. Despite that, it is also here for completeness.
* The 13-limit neutral/supraminor seconds are the ratios of [[14/13]] and [[13/12]], which are about 128{{c}} and 139{{c}}, respectively; 14/13 in particular can also be analyzed as a [[semitone]]. Despite that, it is also here for completeness.


==Categorization==
== In mos scales ==
Intervals between 120 and 171{{c}} generate the following [[MOS|mos]] scales:


Neutral seconds are generally considered to be between 1\9 and 1\7, being half of some sort of minor third. If semifourths are included, they can be as narrow as 1\10.
These tables start from the last monolarge mos generated by the interval range.


===Proposal: Ground's Neutral Second Categorization System===
Scales with more than 12 notes are not included.
{| class="wikitable"
!Range
! colspan="2" |Mos
|-
|120–133{{c}}
|[[1L 8s]]
|[[9L 1s]]
|-
|133–150{{c}}
|[[1L 7s]]
|[[8L 1s]]
|-
|150–171{{c}}
|[[1L 6s]]
|[[7L 1s]]
|}


Import splitting table here.
==Categorization==


===Proposal: Ground's Neutral Second Categorization System===
As neutral intervals, neutral seconds can be named based on interval splitting.
{| class="wikitable"
{| class="wikitable"
|+ Names Based on Interval Splitting (with Nearby Edo Intervals)
|+ Names Based on Interval Splitting (with Nearby Edo Intervals)
|-
|-
! ¢ !! Definition !! Name (accepted names are bold) !! Edo !! ¢ !! Error ¢
! ¢ !! Definition !! Name (accepted names are bold) !! Edo !! ¢ !! Error ¢
|-
| 109.050 || 7/6 / √(6/5) || Sepsemipental Semitone || 1\11 || 109.091 || 0.041
|-
| 111.731 || '''16/15''' || '''Pental Semitone''' || 3\32 || 112.500 || 0.769
|-
|-
| 119.443 || '''15/14''' || '''Septimal Major Semitone''' || 1\10 || 120.000 || 0.557
| 119.443 || '''15/14''' || '''Septimal Major Semitone''' || 1\10 || 120.000 || 0.557
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|-
|-
| 175.489 || <sup>4</sup>√(3/2) || Quadranpyth Major Second || 6\41 || 175.610 || 0.121
| 175.489 || <sup>4</sup>√(3/2) || Quadranpyth Major Second || 6\41 || 175.610 || 0.121
|-
| 182.206 || 6/5 / √(7/6) || Pensemiseptal Major Second || 5\33 || 181.818 || -0.388
|-
| 182.404 || '''10/9''' || '''Minor Whole Tone''' || 5\33 || 181.818 || -0.586
|}
|}

Revision as of 09:36, 11 December 2025


A neutral second, as a concrete interval region, is typically near 150 cents in size, distinct from semitones of roughly 100 cents and major seconds of roughly 200 cents. A rough tuning range of the neutral second is 130 to 170 cents, and they characteristically are half of some kind of minor third. Neutral seconds are not found in diatonic, but they do exist in a diatonic functional context as "neutral" diatonic intervals.

They are one of the most distinctive-sounding yet versatile xenharmonic intervals, which makes them highly valuable.

Function

The large step of armotonic is always some sort of neutral second, which functions similar to both a whole tone and semitone.

A step of 13ed3 is a middle neutral second. It is notable for having an unusually good approximation of LCJI for a system generated by neutral seconds.

Supraminor/submajor scales, such as 2.3.17/7 blackdye, have a large number of neutral seconds.

Porcupine neutral seconds are larger neutral seconds most commonly between 2\15 and 3\22 which, consistent with Porcupine temperament, split a sharp 6/5 in half and a flat 4/3 into thirds. This functionally makes them a very flat minor whole tone (T10/9), and are thus an easy way to make otherwise uninteresting progressions sound xenharmonic.

In larger edos, it's possible to have a similar tuning of intervals, but without Porcupine tempering. In the 100b val, the T10/9 is a slightly larger 168¢ in exchange for making the T81/80 48¢, a much more usable aberrisma than Porcupine typically offers.

In just intonation

By prime limit

The 3-limit does not have a simple neutral second, so we start with the 5-limit:

  • The 5-limit acute minor second or large limma is a ratio of 27/25, and is about 133¢.
  • The 7-limit neutral second is a ratio of 35/32, and is about 155¢.
    • There is also a 7-limit swetismic neutral second, which is a ratio of 49/45, and is about 147¢.
  • The 11-limit neutral/submajor seconds are the ratios of 12/11 and 11/10, which are about 151¢ and 165¢, respectively; 11/10 in particular can also be analyzed as a major second. Despite that, it is also here for completeness.
  • The 13-limit neutral/supraminor seconds are the ratios of 14/13 and 13/12, which are about 128¢ and 139¢, respectively; 14/13 in particular can also be analyzed as a semitone. Despite that, it is also here for completeness.

In mos scales

Intervals between 120 and 171¢ generate the following mos scales:

These tables start from the last monolarge mos generated by the interval range.

Scales with more than 12 notes are not included.

Range Mos
120–133¢ 1L 8s 9L 1s
133–150¢ 1L 7s 8L 1s
150–171¢ 1L 6s 7L 1s

Categorization

Proposal: Ground's Neutral Second Categorization System

As neutral intervals, neutral seconds can be named based on interval splitting.

Names Based on Interval Splitting (with Nearby Edo Intervals)
¢ Definition Name (accepted names are bold) Edo ¢ Error ¢
119.443 15/14 Septimal Major Semitone 1\10 120.000 0.557
121.243 7/6 / 4√(7/5) Quadranseptimal Supraminor Second 1\10 120.000 -1.243
124.511 4√(4/3) Quadranpyth Supraminor Second 3\29 124.138 -0.373
128.298 14/13 Tridecimal Supraminor Second 3\28 128.571 0.273
133.435 √(7/6) Semiseptal Neutral Second 1\9 133.333 -0.102
138.573 13/12 Tridecimal Neutral Second 3\26 138.462 -0.111
140.391 5√(3/2) Quintanpyth Neutral Second 2\17 141.176 0.785
145.628 4√(7/5) Quadranseptimal Neutral Second 4\33 145.455 -0.174
150.637 12/11 Undecimal Neutral Second 1\8 150.000 -0.637
157.821 √(6/5) Semipental Neutral Second 5\38 157.895 0.074
165.004 11/10 Undecimal Submajor Second 4\29 165.517 0.513
166.015 3√(4/3) Trienpyth Submajor Second 4\29 165.517 -0.498
170.013 6/5 / 4√(7/5) Quadranseptimal Submajor Second 1\7 171.429 1.415
175.489 4√(3/2) Quadranpyth Major Second 6\41 175.610 0.121