One functional advantage of a microcontroller over a single-board computer is lower latency due to not having the overhead of an operating system. Also, the Pi

One functional advantage of a microcontroller over a single-board computer is lower latency due to not having the overhead of an operating system. Also, the Pi's built-in audio output is basically unusable, but easily replaced. However if you dont have floating point arithmetic like many microcontrollers, fixed-point DSP for FFT or autocorrelation presents its own set of challenges, which can be either a good thing or a bad thing.