Not to nit pick, but calling the HD1200 a 'gen one class d' when it came out nearly fifteen years after the Mmats I mentioned (and even longer than the super old school Infinity class Ds) is a bit of a disservice. Hell, even the JL Slash series that preceded the HDs were class D for the mono amps. Not that I think they are worth the price premium, but they aren't archaic either.
The jl HD is like 50 percent efficient. Test is on bigd YouTube channel.
They are not anywhere near the best class d design.
The regulation comes at a pretty significant cost.
The mmats is waaay more efficiently run than the jl audio.
1 HD 1200 will dim your head lights. The whole point of using class d is the efficiency. No other reason to use it.
Not to mention the jl cost over a dollar a watt once you pay taxes.
The mmats is a newer more efficient class d that cost about 60 cent a watt.
Annandale the 4 channel HDs are even worse. They have distinct sound to them. I've installed maybe a 1000 of them over the past 10 years. I don't like them at all. If they were free I might use them on my midbass.