Class D amps are simple – just take an input, and use that to modulate a square wave with PWM. Send this PWM signal to a MOSFET or something, and you have the simplest class D amp in existence.

Class-D audio amplifiers are a popular choice for audio amplification due to their high efficiency and compact design. Unlike traditional amplifiers, which dissipate a significant amount of power ...

For added flexibility, the Class D amp also has a variable low pass filter, helping make audio frequency more adjustable according to your subwoofer(s) characteristics and personal listening ...