Here is a method of deriving some tetrachordal like shapes starting with the sub 7-14 series borrowing Schlesinger designation for Mixolydian. It is interesting to note that to derive each form, there is a shift up the subhamonic series by multipling by 2, 3, or 4 times shifting the series to 14-28, 21-42 and 28-56 respectfully to derive a class of scale. The term Tri-Chromatic (formed by multiplying by 3 the 7-14 series) is invented here to designate a new scale type in between the chromatic and enharmonic. In each set of four a different interval acts as a disjunction like interval and greatly expands the range of what a disjunction might be. These being in order 8/7, 11/10, 14/13 then these are repeated in the next three to construct tetrachordal shapes where the large interval is at the bottom as opposed to the top. It was an idea Wilson left unexplored past this page it appears. The other tetrachordal permutations are left unexplored.
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