A class-D amplifier or switching amplifier is an electronic amplifier in which the amplifying devices operate as electronic switches, and not as linear gain devices as in other amplifiers.

Is a Class D amplifier better?

Class A design is the least efficient but has the highest sound fidelity. Class B design is a little more efficient, but full of distortion. Class AB design offers power efficiency and good sound. Class D design has the highest efficiency but isn't quite as high-fidelity.

What is a Class D amp used for?

Class D amps, also known as “digital” amplifiers, work by shifting the sample frequency at which they operate up to extremely high frequencies. In doing so, they use MUCH smaller power transformers which takes up far less interior space—something that is always at a premium in subwoofers.