How do I make Halion Sonic 3 the default player in Dorico?
It isn’t currently possible to change the default from Halion Sonic SE, but we hope to add the option of different HALion plugins in a future version.
But you could at least upgrade HALion Sonic SE 2 to HALion Sonic SE 3.
HALion Sonic SE 3 is available for free, have a look here: https://www.steinberg.net/index.php?id=downloads_halion_sonic_se_3&L=1
HS3 will turn up in the list of instruments in Dorico and you will be able to use it. But by default Dorico will use HSSE, though you can change it later manually (but of course it’s tedious).
What features of HS3 are you after that you want to use in Dorico?
You know? HSSE can also play all sound libraries from HALion Full and Sonic.