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Radian, radial major second, or radial whole tone is an interval of 1200/2pi cents.  
{{Infobox Interval|Ratio=2^(1/(2pi))|Monzo=undefined|Cents=190.98593|Name=radian, radial major second, radial whole tone}}
 
'''Radian''', '''radial major second''', or a '''radial whole tone''' is an interval of <math>\frac{1200}/{2\pi}</math cents.
 
The interval has an interpretation that relates to all [[EDO|EDOs]]. Since pitch classes in all equal divisions of the octave form in the shape of a circle, radian interval therefore occurs as the radius of this perceptional circle.  


{{Infobox Interval|Ratio=2^(1/(2pi))|Monzo=undefined|Cents=190.98593|Name=radian, radial major second, radial whole tone}}
Radian is 13 cents below just [[9/8]] and 9 cents below [[12edo]] major second of exactly 1/6 of a circle, or 200 cents.
 
== Approximations ==
 
Closest equal temperament approximations of the radian can be derived from the continued fraction of 1/2pi: 4\[[25edo|25]], 7\[[44edo|44]], 53\333, and 113\710. 7\44 and 113\710 are complementary to the historically notable 22/7 and 355/113 approximations of pi.
 
Other approximations include 5\[[31edo|31]], which is also for the meantone, 11\69, the local meantone as well, and 13\82. Starting with 88edo, difference between the radian (14 steps out of 88) and 9/8 (15 steps out of 88) is visible.

Revision as of 22:19, 24 September 2021

Interval information
Expression [math]\displaystyle{ 2^(1/(2pi)) }[/math]
Monzo [undefined
Size in cents 190.9859¢
Names radian,
radial major second,
radial whole tone
Special properties reduced

Radian, radial major second, or a radial whole tone is an interval of <math>\frac{1200}/{2\pi}</math cents.

The interval has an interpretation that relates to all EDOs. Since pitch classes in all equal divisions of the octave form in the shape of a circle, radian interval therefore occurs as the radius of this perceptional circle.

Radian is 13 cents below just 9/8 and 9 cents below 12edo major second of exactly 1/6 of a circle, or 200 cents.

Approximations

Closest equal temperament approximations of the radian can be derived from the continued fraction of 1/2pi: 4\25, 7\44, 53\333, and 113\710. 7\44 and 113\710 are complementary to the historically notable 22/7 and 355/113 approximations of pi.

Other approximations include 5\31, which is also for the meantone, 11\69, the local meantone as well, and 13\82. Starting with 88edo, difference between the radian (14 steps out of 88) and 9/8 (15 steps out of 88) is visible.