A subwoofer is a woofer, or a complete loudspeaker dedicated to the reproduction of bass audio frequencies, from 150 Hz down as far as 20 Hz.

The following circuit diagrams shows detail electrical schematic for car subwoofer driver. This device is intended to be connected to an existing car stereo amplifier. This device consists of following parts: Log Potentiometer, Dual gang Linear Potentiometer, 1/4W Resistors, 25V Electrolytic Capacitors, 63V Polyester Capacitors, LED, 100mA NPN Transistors, Dual BIFET Op-Amp, 24 W BTL car radio power amplifier, RCA audio input sockets and 4 Ohm Woofer or two 8 Ohm Woofers wired in parallel.