Is there a theory behind knowing when to break an ostinato pattern?

Question

I happen to like Baroque-style ostinato patterns (mostly broken chords) for use in my compositions, but I'm always a bit unsure when is an opportune moment to break the pattern and change into something new. I usually judge the breaking-off point by the whim of my ear nowadays, i.e., I change whenever I'm starting to feel bored with the pattern.

Is there a more rational way to approach this (like the golden ratio or something), or does it all depend on the composer's innate sense of proportion and/or tolerance of boredom?

Answer 1

I can't think of a singular theory per se, but are you aware of the Gestalt idea of the Implication–Realization Model?

In short—and I'm skipping over a lot of detail and nuance here—it's a theory of pattern completion. Something is implied, and then it is either realized or not.

Similar Gestalt ideas were used by Leonard Meyer (in books like Emotion and Meaning in Music) and other authors to basically suggest that events in a musical work determine its meaning. But those events imply certain consequences, and when our expectations of said consequences are not met, that then creates the emotion of the music. Obviously this is a gross oversimplification, and I hope it goes without saying that this is heavily influenced by culture, but this is the general idea.

As such, one possible theory you could consider is how a given ostinato pattern sets up particular expectations. Depending on how you want your listeners to react (and when?), you can either continue or adjust said ostinato pattern.

Answer 2

One thing I've found to be useful is breaking the pattern for emphasis. One rather trivial example would be a short piece in the common AABA format. One might keep the ostinato from A to A then break it at the end of the second A. The appearance of an ostinato (or other easily heard feature) or its sudden absence signals to the listener that something is about to happen. Of course, one can create surprise by not breaking the ostinato and still making a change in something else (harmony usually.)

Bach's Passacaglia and Fugue in Eb is an example with a continually repeated ostinato. So is Ravel's Bolero (assuming that the snare is really an ostinato.)

Answer 3

If you think one purpose of music is entertaining then your thought

I change whenever I'm starting to feel bored with the pattern.

is a good point to change.

Many people are not interesting in music when it becomes redundant. Others just like this redundancy and can't get enough.

I would change, if I felt that I have nothing more to say. At the moment I'm listening to BWV 1052 where you feel that Bach is just playing around with his motifs:

(2:25-3:25)

(2:12-3:15)

But he is never boring as he creates always new variations.

The idea "to stop, when there's nothing more to say" seems to me to be the difference between pop music and classical music - and their audience and also the reason, why many good musicians hesitate to "compose" their own music.

That's why Webern and Schönberg (et al.) started to write music in 12 tone compositions: The first measures are so ppp that you hardly can hear the music!

Answer 4

Only the 'theory' of balancing the security of repetition against its potential for boredom. A topic on which, say, Mozart and Philip Glass would doubtless have different views!