22/21: Difference between revisions

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{{Infobox Interval
{{Infobox Interval
| Name = small undecimal semitone
| Name = small undecimal semitone, undecimal minor semitone, pentacircle minor second
| Color name = 1or1, loru unison
| Color name = 1or1, loru unison
| Sound = jid_22_21_pluck_adu_dr220.mp3
| Sound = jid_22_21_pluck_adu_dr220.mp3
| Comma = yes
}}
}}
'''22/21''' is a small [[superparticular]] [[semitone (interval region)|semitone]] of about 80.5¢ that appears in [[11-limit]] [[just intonation]], commonly known as the '''small undecimal semitone''', or '''undecimal minor semitone'''. It is the difference between [[12/11]] and [[8/7]], or between [[7/6]] and [[11/9]].


'''22/21''' is a small [[superparticular]] '''semitone''' of about 80.5¢ that appears in [[11-limit]] [[just intonation]]. It makes the difference between the 21st and 22nd [[harmonic]]s. It is close in size to [[21/20]], a 7-limit superparticular interval, differing from it by [[441/440]], about 3..
In many notation systems (e.g. [[FJS]], [[HEJI]]), it is an imperfect unison, as it is the stack of an [[33/32|undecimal quartertone (33/32)]] and a [[64/63|septimal comma (64/63)]], neither of which changes the [[scale|scale degree]] or [[interval quality|quality]]. However, it is only flat of the [[256/243|Pythagorean minor second (256/243)]] by a [[896/891|pentacircle comma (896/891)]]. For this reason it could be called the '''pentacircle minor second'''.  


The single degree of [[88cET]] can function as both 21/20 and 22/21, thus tempering out 441/440.  
Furthermore, it is close in size to [[21/20]], a 7-limit superparticular interval most commonly treated as a minor second, differing from it by [[441/440]], about 3.9¢. The single degree of [[88cET]] can function as both 21/20 and 22/21, thus [[tempering out]] 441/440.


== Approximation ==
10 steps of [[149edo]] appoximate 22/21 with a precision of about 1 part in 15 million, or 1 part in 100000 when measured using [[relative cent]]s.
10 steps of [[149edo]] appoximate 22/21 with a precision of about 1 part in 15 million, or 1 part in 100000 when measured using [[relative cent]]s.



Latest revision as of 11:13, 9 April 2025

Interval information
Ratio 22/21
Factorization 2 × 3-1 × 7-1 × 11
Monzo [1 -1 0 -1 1
Size in cents 80.53704¢
Names small undecimal semitone,
undecimal minor semitone,
pentacircle minor second
Color name 1or1, loru unison
FJS name [math]\displaystyle{ \text{P1}^{11}_{7} }[/math]
Special properties superparticular,
reduced
Tenney height (log2 nd) 8.85175
Weil height (log2 max(n, d)) 8.91886
Wilson height (sopfr(nd)) 23
Comma size medium

[sound info]
Open this interval in xen-calc

22/21 is a small superparticular semitone of about 80.5¢ that appears in 11-limit just intonation, commonly known as the small undecimal semitone, or undecimal minor semitone. It is the difference between 12/11 and 8/7, or between 7/6 and 11/9.

In many notation systems (e.g. FJS, HEJI), it is an imperfect unison, as it is the stack of an undecimal quartertone (33/32) and a septimal comma (64/63), neither of which changes the scale degree or quality. However, it is only flat of the Pythagorean minor second (256/243) by a pentacircle comma (896/891). For this reason it could be called the pentacircle minor second.

Furthermore, it is close in size to 21/20, a 7-limit superparticular interval most commonly treated as a minor second, differing from it by 441/440, about 3.9¢. The single degree of 88cET can function as both 21/20 and 22/21, thus tempering out 441/440.

Approximation

10 steps of 149edo appoximate 22/21 with a precision of about 1 part in 15 million, or 1 part in 100000 when measured using relative cents.

See also