Some comments on the 22-tone Shruti System, Raga Scales and the Khiasmos
There is still material that may be added to Wilson's work on the scale of India. Comment will be limited until such time it is felt complete. Related aspects will nevertheless be grouped together.Many of the documents were done with and were used by Amiya Dasgupta for his North Indian music class at Cal Arts. These papers have been assembled from a variety of times and sources. The dates are the clue to the original grouping.
The "letters' file cover a broad area of subjects. First are the rotations of the Muchana (the 5 limit diatonic scale) to the series of scales providing the 22 tone scale. Next are those scales where an added disjunction size interval (aug. 4th) is added of which there are 10 varieties as shown in the Kalyan variations. Next are alternative 5 limit 22 tone systems some of which have been named followed by those that haven't. It is not clear if the names are a matter of convenience or reflects a stronger tie to the scale named. The last section details different keyboard shapes.
The pages on the Muchanas are based on the Indian scale Kafi. The arrow pointing down shows where the basic scale begins with the 9/8 in parentheses being the disjunction between the two tetrachords. Since in practice Sa and Pa are constants without variation, two possibilities (3 & 4) of the Muchana are omitted from practice. There is an assumption here that the variation under each letter name as in Re, Ga, Ma etc are always 135/128 differences in size that leads to a higher and lower inflection of a 12 tone set. Together the two form a 22 tone array.
Page 6 is a Key to Raga scales showing them derived from 11 of the most important ‘thats’. Some of which are modal variations of the basic Muchana or those containing 2 (disjunction) aug.4th. Wilson points out that not all the possible scales of this sort are used in the Raga system (at least in this mode of the scale). For this reason the numbering system between the various papers here are non consistent. The triangular arrangement is organised to what notes are altered by being lowered (underlined). The bottom row [1-2-3-4] all has lower Re the next one up all lowered Dha [2-3-4-5-6-7] as well as those below to the right, that above all lowered Ga with those likewise to the right and lower [3-4-5-6-7-8-9] with the top row and those below to the right all lowered Na
[4-7-9-10]. A chart stows the same data using western note names.
More to come- in progress
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