An audio signal processing method, which is executed by a processor electronically communicating with a deep neural network within a computing system, may comprise: acquiring, by the processor, an input signal before encoding and an output signal after quantization and decoding; calculating, by the processor, a perceptual global loss for a frame corresponding to the input and the output signals; acquiring, by the processor, a plurality of subframes corresponding to the input and output signals by applying a windowing function to the frame of the input and output signals; calculating, by the processor, perceptual local losses for the plurality of subframes corresponding to the input and output signals; and acquiring, by the processor, multi-time scale perceptual loss based on the perceptual global and local losses.