Class A/AB vs D — Is it Audible in 2021?

As a diyer and sometimes customer, here is my opinion.

1. “Class D have better bass control” is a false statement in science point of view, but a somewhat valid one in commercial device.

Bass control is the combination of high damping factor and output current capacity of amplifier at the low load. Problem is speakers right now, especially bookshelf, have low sensitivity and low impedance with horrible phase in bass region. So the amplifier must be capable to deliver huge current at low impedance. Many amplifiers, especially tube amp or wimpsy amp, are not capable of doing that and reach a point of clipping at that moment. And with nature of clipping, the high THD effect caused by clipping will last a small period of time before it going back to normal. Class D amp, especially the good one, does not suffer from this effect. And that can be a different people heard.

In addition, class D like Hypex uses much more negative feedback than the normal class A/AB out there (Benchmark or Halcro or Soulution aside), so naturally class D amp will have lower distortion than the normal class A/AB on the market. Because of that reasons, the class D will have better bass control than the vast majority of class A/AB in the market. But if you have class A/AB amp with huge amount of current reserve and using good amount of negative feedback, their bass control to your speaker is the same