User:Inthar/Generator variety: Difference between revisions
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== Relationship between step variety and generator variety == | == Relationship between step variety and generator variety == | ||
MOS scales have step variety 2 and generator variety 1, and [[MOS substitution]] scales (including all regular SV3 scales) have step variety 3 and generator variety 2. However, not all scales with generator variety ''n'' have step variety at most ''n'' + 1: Consider a 13-note scale with a well-formed generator sequence GS('''x''', '''y''', '''y''', '''x''', '''y''') and suppose one scale step is reached via 4 generators | MOS scales have step variety 2 and generator variety 1, and [[MOS substitution]] scales (including all regular SV3 scales) have step variety 3 and generator variety 2. However, not all scales with generator variety ''n'' have step variety at most ''n'' + 1: Consider a 13-note scale with a well-formed generator sequence GS('''x''', '''y''', '''y''', '''x''', '''y''') and suppose one scale step is reached via 4 generators. Then the word of stacked generators is '''xyyxyxyyxyxyz''' including the final closing generator '''z''', and there are 4 step sizes: | ||
# 2'''x''' + 2'''y''', | # 2'''x''' + 2'''y''', | ||
# '''x''' + 3'''y''', | # '''x''' + 3'''y''', | ||
# 2'''x''' + '''y''' + '''z''', | # 2'''x''' + '''y''' + '''z''', | ||
# '''x''' + 2'''y''' + '''z'''. | # '''x''' + 2'''y''' + '''z'''. | ||
More trivially, a MOS generator when not stacked so that the resulting scale is a MOS size (denominator of semiconvergent to the generator) will not have variety 2. | More trivially, a MOS generator when not stacked so that the resulting scale is a MOS size (equal to the denominator of a semiconvergent to the generator) will not have variety 2. |