So I'm midway through composing a movement of a suite I am working on and I have reached this section that is primarily triplets. It starts off as a solo violin, and then later, more instruments are slowly added back in. I felt the need for rhythmic variety, so what do I do when I have triplets as the primary rhythm? In this case, I went for the polyrhythm option. Polyrhythm has worked for me before to bring rhythmic interest. However, something happened that I did not expect. The rhythms clashed noticeably. I knew rhythmic dissonance was a thing, but that has never occurred in my own works until now. Here is an excerpt that includes the polyrhythm:
By the way, this passage here starts in G minor and modulates to C minor briefly. Considering that the movement as a whole is in D minor, that's not too surprising. And it can't be the harmony that is making it clash, since outside of a few non-chord tones, all the voices are consonant with each other. That's why I'm thinking that it is the rhythm that is making it clash. However, as I stated before, I have never had rhythmic dissonance happen with polyrhythms before(and that is both for 2:3 and 4:3 polyrhythms).
Here is an example of a piece where I use polyrhythms and don't get this rhythmic dissonance:
But it isn't just piano solo for which I have gotten polyrhythms to not be rhythmically dissonant, I have done that for chamber works too. And I have never used polyrhythms outside of x:3 because if triplets are the primary rhythm, rhythmic dissonance is less likely to occur than with say quintuplets as the primary rhythm. And before you say that it is probably the tempo, the tempo that this movement is at is quarter note = 100 BPM, which again, I have wrote polyrhythms at that exact tempo that aren't rhythmically dissonant, so that's ruled out. In fact, I find that the moderate range is where polyrhythm is at its best. Too slow and it might as well be polymeter instead of polyrhythm. Too fast and it might as well be a single rhythm that is very embellished.
So why am I getting this rhythmic dissonance if my tempo is not too fast or too slow and my harmony is consonant? And is there anything I can do to keep the polyrhythm but not have the rhythmic dissonance? Transposing the harmony down I don't really want to do because Violin II is already getting close to its lower bound. If I transpose it down, it will be at its lower bound, an open G, which is not easy to control in terms of intonation and dynamic. Plus, I'm not sure that changing the notes of Violin II would effect the rhythmic dissonance at all.