Thanks for your response.

No, the USB cable is the only link. That is primarily for midi, and I would have thought, solely for midi.

That's what lead me to ask the second part of my question. I think in general RealBand, like BIAB, has the capability to 'render' a 'song' to audio. Could something like that be what's going on here?

I note your comment about the Preferences. But clarifying the small print is quite important. If it is the EK-50's own sounds that are being recorded, that's a real plus. But I'm not interested in some render using (perhaps?) the Windows synth.