A Perfect Fifth divided into four subintervals by five tones.
In musical practice, most pentachords consist of a tetrachord with a whole tone added at either the top or bottom.
The addition of Hyperhypate, a tone 9/8 below the tonic to the Chromatic and Enharmonic Dorian modes converts the scale from two disjunct tetrachords separated by a 9/8 in one octave to one consisting of two conjunct pentachords spanning a Major Ninth (9/4).
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