| 摘要 |
PROBLEM TO BE SOLVED: To automatically adjust sound volume to the best sound volume for a singer and listeners. SOLUTION: A microphone 2a is provided with an infrared-ray emission part and sensors 15-1, 15-2, 15-n, etc., which receive infrared rays are arranged nearby speakers 14-1 to 14-n. The output signals of the sensors are received and A/D-converted into numerals, which are compared with one another to select the system having the largest light reception quantity; and the gain of the volume control part 12 of the selected system is increased to increase the sound volume of its speaker 14 and gains of volume controls of other systems are controlled to default values. |
