page_title: Pyknon
section_title: Scale structure
hierarchical_section_title: Pyknon / Scale structure
caption_attribution_description: English: Ancient Greek Mixolydian tonos on E, in the chromatic genus, with tetrachords labeled
context_page_description: Pyknon, sometimes also transliterated as pycnon in the music theory of Antiquity is a structural property of any tetrachord in which a composite of two smaller intervals is less than the remaining interval. The makeup of the pyknon serves to identify the melodic genus and the octave species made by compounding two such tetrachords, and the rules governing the ways in which such compounds may be made centre on the relationships of the two pykna involved.
context_section_description: A further refinement of tetrachordal construction, according to Aristoxenus, is that the lower interval of the pyknon must be smaller than or equal to the upper one (Barbera 1984, 229–30). Didymus in the chromatic genus and Archytas in the enharmonic broke this rule, however, and in the Harmonics (2. 13) Ptolemy criticized this feature in Didymus, holding that it is unmelodic and out of agreement with the evidence of our ears (West 1992, 170).
  According to Aristoxenus (Elements of Harmony, book 2), whenever tetrachords are combined to form a scale filling an octave, "Two consecutive pycna may not occur in ascent or descent. A ditone may precede or follow [a pycnon] in ascent or descent. A tone may follow [a pycnon] only in descent" (Mathiesen 1999, 331).
caption: Greek Mixolydian octave species on E in the chromatic genus: conjunct tetrachords a and b, with note of conjunction c, and interval of disjunction d; the two pykna are separated by the larger interval between steps 3 and 4 About this soundPlay (help·info)
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