AID: Difference between revisions
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For an intervallic system with <u>n</u> divisions, [http://sites.google.com/site/240edo/arithmeticirrationaldivisions%28aid%29 AID] is considered as [http://www.richland.edu/james/lecture/m116/sequences/arithmetic.html arithmetic sequence] with divisions of system as terms of sequence. | For an intervallic system with <u>n</u> divisions, [http://sites.google.com/site/240edo/arithmeticirrationaldivisions%28aid%29 AID] is considered as [http://www.richland.edu/james/lecture/m116/sequences/arithmetic.html arithmetic sequence] with divisions of system as terms of sequence. | ||
If the first division is <u>A1</u> and the last , <u>An</u> , with common difference of <u>d</u> , we have : | If the first division is <u>A1</u> and the last, <u>An</u> , with common difference of <u>d</u> , we have : | ||
:: A1 = A1 | :: A1 = A1 | ||
:: A2 = A1+d | :: A2 = A1+d | ||
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As we can consider <u>Sn</u> of system to be 1200 cent or anything else (octavic or non-octavic system ) then <u>d</u> is most important to make an AID with n divisions with A1. So, the common difference between divisions is : | As we can consider <u>Sn</u> of system to be 1200 cent or anything else (octavic or non-octavic system ) then <u>d</u> is most important to make an AID with n divisions with A1. So, the common difference between divisions is : | ||
:: '''d =( <u>2(Sn - nA1))/ | :: '''d =( <u>2(Sn - nA1))/(n(n-1))</u>''' | ||
By considering Sn=1200 , A1=70 , n=12 , d will be 5.454545455 and our 12-tone scale is equal to: | By considering Sn=1200, A1=70, n=12, d will be 5.454545455 and our 12-tone scale is equal to: | ||
:: '''0.0 70.0 145.455 226.364 312.727 404.545 501.818 604.545 712.727 826.364 945.455 1070.0 1200.0''' | :: '''0.0 70.0 145.455 226.364 312.727 404.545 501.818 604.545 712.727 826.364 945.455 1070.0 1200.0''' | ||
Scales based on AID can be subsets of EDO if: | Scales based on AID can be subsets of EDO if: | ||
# we choose d=0 so , A1 = Sn/n .. Consider <u>n</u>=8 and <u>A1</u>=150 , then we have 8-EDO . | # we choose d=0 so, A1 = Sn/n .. Consider <u>n</u>=8 and <u>A1</u>=150, then we have 8-EDO . | ||
# for a constant <u>n</u> and different <u>A1</u>, if <u>d</u> and (Sn/A1) are integers, we have a subset of EDO or EDI (Equal divisions of Interval). | # for a constant <u>n</u> and different <u>A1</u>, if <u>d</u> and (Sn/A1) are integers, we have a subset of EDO or EDI (Equal divisions of Interval). | ||
Consider <u>Sn = 1400</u> , <u>n</u>=8 and <u>A1</u>=70 , then we have a subset of a 140-ED (1400.) with Degrees as 7 17 30 46 65 87 112 140 : | Consider <u>Sn = 1400</u> , <u>n</u>=8 and <u>A1</u>=70, then we have a subset of a 140-ED (1400.) with Degrees as 7 17 30 46 65 87 112 140 : | ||
:: 0.0 70.0 170.0 300.0 460.0 650.0 870.0 1120.0 1400.0 | :: 0.0 70.0 170.0 300.0 460.0 650.0 870.0 1120.0 1400.0 | ||
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AID system shows different ascending, descending or linear trend of change in divisions sizes due to relation between n and A1 in AID and EDO with equal degree: | AID system shows different ascending, descending or linear trend of change in divisions sizes due to relation between n and A1 in AID and EDO with equal degree: | ||
* If choosing <u>A1</u> greater than division size in equal degree EDO , <u>d</u> is negative and <u>AID</u> is descending. | * If choosing <u>A1</u> greater than division size in equal degree EDO, <u>d</u> is negative and <u>AID</u> is descending. | ||
* If choosing <u>A1</u> smaller than division size in equal degree EDO , <u>d</u> is positive and <u>AID</u> is ascending. | * If choosing <u>A1</u> smaller than division size in equal degree EDO, <u>d</u> is positive and <u>AID</u> is ascending. | ||
* If choosing <u>A1</u> equal to division size in equal degree EDO , <u>d</u> is zero. | * If choosing <u>A1</u> equal to division size in equal degree EDO, <u>d</u> is zero. | ||
[[file:AIDO-custom-size-298-402.jpg]] | [[file:AIDO-custom-size-298-402.jpg]] | ||
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[[Category:AID]] | [[Category:AID]] | ||
[[Category: | [[Category:Shaahin Mohajeri]] | ||
[[Category: | [[Category:Todo:cleanup]] |