SPEAKER INPUT CONTROLLING CIRCUIT

PURPOSE:To slove problems at large input and to extend low sound reproducing region, by providing a feedback variable means changing an output being a feedback signal to an amplifier in response to an output of a comparator. CONSTITUTION:A voltage applied to an amplifier 1 is amplified and the output is applied to an HPF2. The HPF2 has the same characteristics as a speaker connected to the amplifier 1 and the output of the HPF2 and the input of the amplifier 1 are compared at a comparator 3. The output of the comparator 3 is fed back to the amplifier 1 via a feedback amount variable means 4. The gain of the means 4 is changed in response to the magnitude of the output of the comparator 3 to be the input; for example, when the output of the comparator 3 is larger, the feedback amount is decreased and when the output of the comparator 3 is smaller, the amount is increased. Thus, problems such as clip can be solved at large input and the extension of low sound reproducing region can be made for normal input.