So, I’ve been doing a bit of reading, and asked a questions on another forum, and it looks like this is more specifically what I need to do (according to Y(J)S’s reply on the dsprelated.com forum):

- Find the root of the LPC denominator polynomial
- Modify the pole angles and recompute the complex poles (with the original abs(?))
- Find the coefficients of the new denominator polynomial

I’m looking for root-finding algorithms in C at the moment. Maybe you have a recommendation for one fast enough to run in realtime on an M4?