method and related apparatus for canceling vocal portions containing in two signals of two stereo channels and providing two corresponding output signals . the method includes : generating a mono signal according to a sum of the signals of the stereo channels ; respectively performing vocal cancellation to each signal of one stereo channel according to a difference between the signal of the stereo channel and the mono signal , and performing low - frequency band and high - frequency band compensation to results of vocal cancellation to generate the two output signals . because vocal cancellation is performed for respective signal of one stereo channel , the two output signals will have substantial difference in frequency band other than the high - frequency band to increase effect of stereo .