A Subwoofer is a loudspeaker which produces audio signals of low frequencies. The first subwoofer amplifier was developed in 1970 by Ken Kreisler. It is basically used to improve the bass quality of audio signals. Here Electronicshub team designs a subwoofer amplifier producing audio signals at low frequencies from 20 Hz to 200Hz and with an output power of 100W, used to drive a 4 ohm load.
Subwoofer Amplifier Circuit Principle:
Audio Signal is first filtered to remove the high frequency signals and allow only the low frequency signals to pass through it. This low frequency signal is then amplified using a voltage amplifier. This low power signal is then amplified using a transistor driven class AB power amplifier.
The amplifier in the diagram will not work for at least 2 reasons:
Q2 har no DC bias.
It will have a high crossover distortion. It does not have any circuit to ensure a idle current in the output transistors.