I think there may be no way to integrate real plainchant with modern notation, or mixed in with other independent musical ingredients. Or at least not in a strict tempo. And definitely no fixed meter.
I’ve been listening and writing, and when I struggle to write some chant I relisten to real chant and notice things I hadn’t noticed before. For example, the quarter note is nowhere near as dominant as I thought. There are eights and half notes all over the place. And the 1 and 5 aren’t quite as dominant as I thought. Sometimes you need to start and stop somewhere else. Chant writing seems to be a situation where you have to work very hard for the chant to stay interesting but also never break out out chant into something other.
Right now I’m writing raw chant, with no words and that might be a mistake but I’m doing it anyway. I think I need to write up about 150-250 measures of independent chant to be ready for something more. I am finding that I am learning and getting better, although I am definitely not there yet.
Looking at other pieces, more modern pieces, that use a structure like a chant it is clear that the chant has been domesticated. Maybe the biggest move to make something chant-like is to be in mixed meter controlled by the text. That doesn’t seem like it will be hard to do. But when you regularize the beat you start to be doing something that is not far away from simply writing a tune without a lot of leaps and returns to hover tones or pedal tones. I’m thinking here of unison mixed meter openings if two pieces I’m conducting for The New Haven Oratorio Choir: Britten Festival Te Deum and Howells Te Deum.
I read these as chant influenced melodies setting old sacred texts. This seems like a much more realistic goal than learning precisely how to write in the style of Hildegard. That task looks like it could be a third of a dissertation for a doctorate. And that’s too much for me. My main goal is to write something that doesn’t sound like the piece I just wrote – Be Still and Know that I Am God. I don’t know if I can go deeply into chant and truly mimic, although I am a decent mimicker. But I can certainly write a piece that has unison chant-influenced melodies in it. With one of those I feel all but forced to do this with organ. It doesn’t feel like it would work with piano one bit and left alone it is barren to the point that I think it would be off putting.
But for right now all I need to do is write my 150-250 measures of chant and keep listening to what Hildegard does to avoid traps of boredom or disconnection and chaos. I might try other chant writers too but for now I want to stay focussed. So this is what I will be doing for the next while.