45/28: Difference between revisions

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+ twelfth complement
Rework to reflect the progress thanks to the establishment of the aberschisma
 
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{{Infobox Interval
{{Infobox Interval
| Name = septimal wide minor sixth, marvel-ptolemaic minor sixth, hemifamity augmented fifth
| Name = septimal wide minor sixth, marvel-ptolemaic minor sixth, aberschismic augmented fifth
| Color name = ry5, ruyo 5th
| Color name = ry5, ruyo 5th
}}
}}
'''45/28''', the '''septimal wide minor sixth''', or '''marvel-ptolemaic minor sixth''', is an interval that is sharp of the [[128/81|Pythagorean minor sixth]] by [[3645/3584]], i.e. a [[81/80|syntonic comma]] plus a [[225/224|marvel comma]]. It is only a third of a [[cent]] sharper than the 13\19 minor sixth of [[19edo]]; however, it functionally doubles as a type of augmented fifth, sharp of the [[6561/4096|Pythagorean augmented fifth]] by [[5120/5103]]. This gives rise to the name '''hemifamity augmented fifth'''.  
'''45/28''', conventionally known as the '''septimal wide minor sixth''' or '''marvel-ptolemaic minor sixth''', is an interval that is sharp of the [[128/81|Pythagorean minor sixth]] by [[3645/3584]], i.e. a [[81/80|syntonic comma]] plus a [[225/224|marvel comma]]. However, it functions more commonly as an augmented fifth, sharp of the [[6561/4096|Pythagorean augmented fifth]] by an [[aberschisma]]. This gives rise to the more precise name '''aberschismic augmented fifth''', and in fact it arises as the result of stacking certain [[9-odd-limit]] consonances – of [[5/4]] and [[9/7]], and of [[9/8]] and [[10/7]].
 
== Temperaments ==
[[Marvel]] tempering equates this interval with the [[8/5|classical minor sixth]] and turns chords like 1–5/4–8/5 or 1–5/4–14/9 into [[essentially tempered chord]]s.
 
== Approximation ==
This interval is only a third of a [[cent]] sharper than 13\19, the minor sixth of [[19edo]].  
 
{{Interval edo approximation|45/28}}


== See also ==
== See also ==
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[[Category:Fifth]]
[[Category:Fifth]]
[[Category:Augmented fifth]]
[[Category:Augmented fifth]]
[[Category:Hemifamity]]
[[Category:Aberschismic]]
 
{{Todo|add sound example}}
{{Todo|add sound example}}

Latest revision as of 19:32, 30 July 2026

Interval information
Ratio 45/28
Factorization 2-2 × 32 × 5 × 7-1
Monzo [-2 2 1 -1
Size in cents 821.3978¢
Names septimal wide minor sixth,
marvel-ptolemaic minor sixth,
aberschismic augmented fifth
Color name ry5, ruyo 5th
FJS name [math]\displaystyle{ \text{A5}^{5}_{7} }[/math]
Special properties reduced
Tenney norm (log2 nd) 10.2992
Weil norm (log2 max(n, d)) 10.9837
Wilson norm (sopfr(nd)) 22
Open this interval in xen-calc

45/28, conventionally known as the septimal wide minor sixth or marvel-ptolemaic minor sixth, is an interval that is sharp of the Pythagorean minor sixth by 3645/3584, i.e. a syntonic comma plus a marvel comma. However, it functions more commonly as an augmented fifth, sharp of the Pythagorean augmented fifth by an aberschisma. This gives rise to the more precise name aberschismic augmented fifth, and in fact it arises as the result of stacking certain 9-odd-limit consonances – of 5/4 and 9/7, and of 9/8 and 10/7.

Temperaments

Marvel tempering equates this interval with the classical minor sixth and turns chords like 1–5/4–8/5 or 1–5/4–14/9 into essentially tempered chords.

Approximation

This interval is only a third of a cent sharper than 13\19, the minor sixth of 19edo.


Edo approximations for 45/28 (821.40 ¢)
≤ 80edo, relative error ≤ 10%
Edo Step size Cents (¢) Absolute error (¢) Relative error (%)
3 2\3 800.00 -21.40 -5.35
16 11\16 825.00 +3.60 +4.80
19 13\19 821.05 -0.35 -0.55
22 15\22 818.18 -3.22 -5.90
32 22\32 825.00 +3.60 +9.61
35 24\35 822.86 +1.46 +4.26
38 26\38 821.05 -0.35 -1.09
41 28\41 819.51 -1.89 -6.44
51 35\51 823.53 +2.13 +9.06
54 37\54 822.22 +0.82 +3.71
57 39\57 821.05 -0.35 -1.64
60 41\60 820.00 -1.40 -6.99
70 48\70 822.86 +1.46 +8.51
73 50\73 821.92 +0.52 +3.16
76 52\76 821.05 -0.35 -2.19
79 54\79 820.25 -1.14 -7.54

See also