Glad to see the hexachord getting some love in the episode. Just wanted to point out that while you’re absolutely correct the semitone is the crucial feature in hexachordal construction, the Guidonian solmization actually includes six vocables - ut re mi fa sol la - originating from the hymn “Ut queant laxis”. More important, the note B is not exactly a recent invention, but a well used note in modal music (though you’re correct that “si” is. But since we’re effectively working with movable do, the two do not equate). In fact, the note B was such a contentious note that its inclusion gave rise to the two types of hexachords - hexachordum durum with b natural, and hexachordum molle with b flat - where the German dur and moll got their names. It is also why the German b natural is denoted as H. I speak in a bit more details on these points in a recent writing on Renaissance flutes (https://thepseudointellectual.substack.com/p/a-history-of-the-flute-in-three-parts). Please don’t hesitate to reach out with any issues or spotted errors.
Glad to see the hexachord getting some love in the episode. Just wanted to point out that while you’re absolutely correct the semitone is the crucial feature in hexachordal construction, the Guidonian solmization actually includes six vocables - ut re mi fa sol la - originating from the hymn “Ut queant laxis”. More important, the note B is not exactly a recent invention, but a well used note in modal music (though you’re correct that “si” is. But since we’re effectively working with movable do, the two do not equate). In fact, the note B was such a contentious note that its inclusion gave rise to the two types of hexachords - hexachordum durum with b natural, and hexachordum molle with b flat - where the German dur and moll got their names. It is also why the German b natural is denoted as H. I speak in a bit more details on these points in a recent writing on Renaissance flutes (https://thepseudointellectual.substack.com/p/a-history-of-the-flute-in-three-parts). Please don’t hesitate to reach out with any issues or spotted errors.