Circuit Project Electronic

This be subwoofer filter low pass frequency circuit, for filter especial low frequency has passed by still the amplifier microphone. By this circuit uses op-amp IC number LF347 , perform the circuit filters low frequency change well, It make the sound that go out to have only low frequency ,about 100HZ not exceed. By have Switch choose frequency level that can want as well. This circuit should choose high-quality equipment, because decrease the noise. The detail is other , see in the circuit.