I am looking for a way to remove a known signal, A, of fixed length, from an unknown audio stream, B, when signal A can be mixed into signal B at any point in time. I may be mistaking but converting signal A to the frequency domain and performing an STFT where the window is approximately the size of the data buffer of signal B then subtracting these wouldn't work because the amount of signal A that may be contained in signal B is unknown.
Simply, i want to do live noise removal, when the noise is known. What are some methods of approaching this?