Hi James. I haven’t used Virtuoso for a while as I have a Smyth Realiser at home - I mainly use Virtuoso when I travel. However, I have just fired it up on my Macbook Pro, and I also got 2 channel sound with Roon!. So then I checked the Audio Midi, Blackhole and Virtuoso settings were correct - see below.
I then checked my Roon signal path again - it was correctly set to 5.1 or 7.1 channels, but was down mixing to stereo because I had the convolution engine modifying my headphone response curve. That only works for stereo, hence the downmixing. I took out the convolution stage, and multi-channel is working correctly - see graphic below (I used an old quad file for testing). Hope this helps. I would be happy to look at your signal path if you still have problems.
