I love Python a lot and I’m first to criticise people complaining about performance when it’s irrelevant (if you’re doing long calculations in NumPy or whatever then the Python overhead is small relative to the hot path).
But as others have said, it’s not a great tool for real time audio since that overhead starts to be a larger % of the time spent. You might want to try compiling parts of it with Cython and using the C API of numpy with that (you can do cimport numpy in your Python code and it’ll remove much of the overhead as it’ll call the C functions directly rather than their wrappers).
Cython and related tools will be the direction to take if performance becomes a bottleneck indeed! Interestingly enough, the audio callback is being handled fast enough on my not-impressive laptop and CPU usage has been low on average (<1%), so Python trickery hasn't been needed yet
But as others have said, it’s not a great tool for real time audio since that overhead starts to be a larger % of the time spent. You might want to try compiling parts of it with Cython and using the C API of numpy with that (you can do cimport numpy in your Python code and it’ll remove much of the overhead as it’ll call the C functions directly rather than their wrappers).