Betarabian comma

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Interval information
Ratio 264627/262144
Factorization 2-18 × 37 × 112
Monzo [-18 7 0 0 2
Size in cents 16.320891¢
Name Betarabian comma
Color name L1oo-2, Lalolo comma
FJS name [math]\text{m}{-2}^{11,11}[/math]
Special properties reduced,
reduced harmonic
Tenney height (log2 nd) 36.0136
Weil height (log2 max(n, d)) 36.0272
Wilson height (sopfr (nd)) 79
Harmonic entropy
(Shannon, [math]\sqrt{n\cdot d}[/math])
~3.34772 bits
Comma size small
open this interval in xen-calc

The Betarabian comma (monzo[-18 7 0 0 2, ratio: 264627/262144) is an 11-limit comma at about 16.3 ¢. It is the sum of the schisma and the biyatisma, as well as the sum of the Alpharabian comma and the rastma. Furthermore, it forms the difference between various pairs of enharmonic quartertone-based intervals in no-fives no-sevens just 11-limit tuning. The term "Betarabian" is a derivative of "Alpharabian", and was coined on account of both the rastma being a comma which separates primary and secondary 11-limit intervals and the term "Alpharabian" itself containing the word "Alpha" within it.


As the Betarabian comma is the sum of the Alpharabian comma and the rastma, it is automatically tempered out whenever the rastma is added to the list of commas tempered out among alphaxenic rank-3 clan; however, there are other temperaments that temper out just the Betarabian comma itself. When tempered out in the 11-limit, it is the betaxenic temperament, or in the 2.3.11 subgroup, the betaxenean temperament.