The long and short of it is: if I drag any instrument besides a Natural Horn patch into my VS Instruments Pro cell, it plays just fine. But if I drag a Natural Horn patch in (I've tried about a dozen now), I see all the expected MIDI activity indicators, but I get no sound. I drag Natural TRUMPET back into the cell and it plays fine. Drag a different Natural Horn patch in -- visual MIDI activity but no sound.
(Of course I am mindful that you can only use the notes enabled for any given instrument. I've even tried doing a gliss over all 88 keys and still nothing out of the Natural Horn.)
As I switch back and forth between, say Natural Trumpet and Natural Horn, I'm touching no other settings, so Volume (MIDI 7) remains up, etc.
I'm running VS Instruments Pro on VS Ensemble Pro, connected to Cubase Pro 9, all on Windows 7. All the latest versions/service packs/patches.
All the patches I've tried in this debug session play fine EXCEPT Historic III/Natural Horn.
I'm a long time user of VS with some fairly large ensembles (100+ tracks), so I like to think I grasp the basics at least. But it certainly wouldn't be my first time making some bonehead mistake. Meanwhile, this one has me stumped!
William Zeitler