I’ve just discovered that this might not be a Roon problem after all. I will dig deeper and see if there is some kind of version conflict between OS X (10.11.6) and the Ravenna Virtual Audio Device driver from Merging - latest build.
I’ve installed the Roon Core on a Mac Mini Server with a 2 GHz i7 processor and 4 gB RAM. Intel HD Graphics 3000. I have a Thundebolt-to-network adapter that connects directly to my Hapi and I usually map the 8 analog outputs first and then the headphone (becomes ch 9-10). The server is also connected using the built-in network connector to the network in my house and a WiFi router.
I wanted to have the Roon Core on the server, since that machine is always running.
I am an audio engineer/producer and I have the Dropbox folder on an external USB drive. When I produce a new mix, I put that into the Dropbox and then I can listen to it with Roon in many places in the house (even on my Sonos system). The audio files are usually in the FLAC format, but sometimes MP3/AAC. Sampling frequencies up to DXD, or DSD256.
Stereo and 5.1.
I’ll see what I can find out about the Ravenna driver and get ack.