Here is the circuit diagram of an easy subwoofer filter that can be operated from a 12V DC supply. Such a circuit is incredibly helpful in automobile subwoofer applications. The circuit is nothing however a low pass filter whose pass frequency can be adjusted between 60 to 160 Hz.
The circuit is designed based on the TL072 dual BIFET opamp IC. Out of the two opamps inside the chip, IC1A is wired as a buffer. The left and right audio inputs when mixing is fed to the input of the IC1A using the DPDT switch S1. Switch S1 is the part control switch which can be used to create the subwoofer in part with different speakers. When S1 is in position 2, 180 degree part shift will be induced.POT R7 can be used for controlling the level. IC1B forms the low pass filter whose pass frequency can be controlled by adjusting the dual gang POT R13.
The circuit is designed based on the TL072 dual BIFET opamp IC. Out of the two opamps inside the chip, IC1A is wired as a buffer. The left and right audio inputs when mixing is fed to the input of the IC1A using the DPDT switch S1. Switch S1 is the part control switch which can be used to create the subwoofer in part with different speakers. When S1 is in position 2, 180 degree part shift will be induced.POT R7 can be used for controlling the level. IC1B forms the low pass filter whose pass frequency can be controlled by adjusting the dual gang POT R13.
