Abstract: A digital audio signal processing method includes establishing a first frequency response corresponding to an audio signal, generating a second frequency response based on the first frequency response, and using the second frequency response to process the audio signal. The first frequency response has a plurality of first sampling points and a plurality of first amplitudes corresponding to the first sampling points respectively. The second frequency response is generated from selecting a portion of the first sampling points as second sampling points and corresponding first amplitudes as second amplitudes, in which the number of the second sampling points is less than the first sampling points. The second frequency response is used to process the audio signal through a convolution algorithm.