Simagic P-HPR input voltage vs output power

Using the Fosi Audio ZK-1002D power amplifier, which is a clone of the Nobsound, testing with different voltage inputs
12V ~ 5W
19V ~ 12W
24V ~ 18W
This is a massive change on the output, if you go with a power amplifier instead of the Simagic haptic box you should buy a 24V power supply to get the max output from it.