| 摘要 |
PURPOSE:To prevent the sound volume change of a speaker by connecting an artificial load having an impedance equivalent to a speaker separated to an output end when one side terminal of a sound signal generating source is separated from the speaker. CONSTITUTION:An artificial load 7 having an impedance equivalent to a first speaker lb is equipped, when a second sound signal generating source 5 and the first speaker 1b are connected by a switching means 6 and a first voice signal generating source 2 is separated, the artificial load 7 is connected to the output end of the separated first sound signal generating source 2. Thus, in any case when the first and a second speakers 1b and 1a are driven by the output of the first sound signal generating source 2 and when only the second speaker 1a is driven, since a load impedance connected with the output end of the switching means 6 side of the first sound signal generating source 2 is equal, an output level supplied to the second speaker 1a is constant and a sound volume change incidental to the operation of the switching means 6 is prevented. |
