To automatically set a delay time of a speaker of a display device in relation to a delay time of a speaker connected to an AV amplifier.

A test signal is transmitted from the AV amplifier to the display device, the test signal is reproduced from the speaker of the display device, and the test signal is received by a microphone arranged at the position of a listener, and thereby, a test signal arrival time is measured. Based on the test signal arrival time of the speaker of the display device and the test signal arrival time of the speaker connected to the AV amplifier, the delay time of the speaker of the display device and the delay time of the speaker connected to the AV amplifier are calculated and stored in relation to each other.