Unsound ,
I won't disagree, i can only express my involvement at many levels and again iterate that I find high Class-A Bias amplifiers not to sound like live music IMO, tending to be soft and laid back ( gentle) and nothing like the recording or live music, of course there are exceptions, but for the most part, , yes, this has been my observation.
Again speaker topology play's a big role here and of course there are those that prefer soft and gentle to
"real " and if you have a speaker which is forward sounding or "bright" it will have an issue on anything but Class-A.
Class- D have what i speak of in spades, unfortunately other issues with that topology leaves it a bit dry making ClassA/AB still the best output stage topology IMO.
regards,