but do need the frequency range at the bottom to not be rolled off.
Frequency range down low and control at those frequencies are two different things that an amp has to have. Just because an amp goes low, doesn’t mean it has control.
Control in the low bass with speakers that have low impedance and high negative phase angles at those frequencies, means an amp that not only goes low in frequency, but one that has to have good wattage, high current ability, and low output impedance/high damping factor, as to keep the bass drivers cone under control.
Some Class-D’s excel in this department, but to me that’s where it stops with them, for now. Maybe in the future when technology catches up and the switching frequency triples, they will be as good if not better in the other areas as well.
Cheers George