Now that's either INCREDIBLE efficiency, or incredible marketing. I know that class D can get close to 90% efficiency, but regardless of that, at 1600W out with 90% efficiency you still have 160W to dissipate. And that requires a whole lotta heatsink.
Someone brought up the notice that amplifier power ratings are given at 1/8 output power, and most music has an average of 1/8 peak and even lower. Mkay, let's split 160W/8. That gives 20 watts. You STILL need a heatsink to dissipate those 20 watts, and i don't see any in there.
It's true that class D is small and efficient - i just finished designing and building a class A headphone amplifier, it's 100% of my own design and execution, i studied, did the math, simulated, and the end result? Worked first time and packs quite a punch (i think i'm gonna need new headphones soon
Now, this class A audio amp of mine, in a basic configuration, 3 transistors per channel (one preamp, one buffer stage and one output stage), outputs 0.15W per channel while drawing... erm... wait for it... 12 watts.
The heatsinks for the output transistors came from a 300W
switching power supply. They used to be fan-aided in the power supply but still it's a good comparison, class A is a big energy waster. Oh and i didn't even mention the amount of filtering required so i don't get mains hum in my 'phones.
A good class AB amp can go up to 70% efficiency, while class D reaches 90%. But it still isn't enough to get 1.6kW out of an empty box. If you look at car audio amps with their outrageous power ratings, at least they have an all-metal body which also serves as a large heatsink. While here... erm... no.