As title says:
Set up to my soundcard (Audiofire 2)
Program keyboard shows notes depressed via mouse and via my keyboard controller (Kawai Es100 via the Audiofire MIDI)
Meters respond to said presses
Nil sound from speakers/phones etc - opening up Audiofire console, nil audio coming through
Opening in SPlat as Vst3, works perfectly
Sometimes hangs audio driver from standalone
 
For comparison- Kontakt 5 works in standalone
But other CW products don't.
 
any ideas?

no ideas?
FWIW the set up for Rap Pro (and the other CW synths) on the audio interface side is pretty lame (unless it's just on my system)
i do wonder if it's the lack of Win 10 drivers for the Audiofire and some advanced use of the audio capabilities in Windows by CW - the drivers are for Win 8.1 as Echo discontinued their studio interfaces
any CW employees have an idea?
it's not a big problem, as I can still use in Sonar, but it does perhaps limit how often i would just turn on the PC to mess around with it

I do not believe the minihost CW uses has changed in some time. It is simple but seems to work OK on my PC. I do not have the same interface, driver support may be the issue. I have everything setup at 44.1K. There are alternatives to the minihost provided by Cakewalk. SAVIHost is a similar idea. Then there are other lightweight hosts such as VSTHost and Cantabile which may also work better.
 
If you want to have a discussion about it with Cakewalk directly this is a better option.

I have yet to see Cakewalk's standalone host work on any of my systems.  I've been using SAVIHost for years.