A signal processor that performs crosstalk cancellation on an audio signal that is input, in a distorted acoustic space where two speakers are placed, the two speakers including an X-side speaker and a Y-side speaker, where X denotes one of left and right, and Y denotes the other of left and right. The signal processor causes the Y-side speaker to output a sound of the audio signal and causes the X-side speaker to output a sound of a signal obtained by processing the audio signal using transfer function GCY, where a transfer function between the Y-side speaker and the Y-side ear is defined as GYY, a transfer function between the X-side speaker and the Y-side ear is defined as GXY, and a transfer function obtained by dividing the transfer function GYY by the transfer function GXY is defined as GCY.