| 摘要 |
PURPOSE:To automatically turn down sound volume by outputting sound according to a case where a person listens to the car audio of a car stereo, etc., in an automobile. CONSTITUTION:By the sound volume controlling method for a car audio controlling the sound output of the car audio 19 mounted on a vehicle by synchronizing the output with the rotation of an engine 1, a pulse signal 9 synchronized with the rotation of the engine is picked up. By defining this pulse signal 9 as a sound volume adjusting signal 18 according to the number of rotation or rotation speed of the engine, the sound output from a car audio 19 is controlled. |
