Hardware Configuration

I have two Audio Science ASI6044 cards installed to an Ubuntu 20.04 server. This gives me 16 mono channels out, or 8 stereo channels. How can I configure the LibreTime to use a specific output? (I have installed the official driver from AudioScience, which recommends ALSA. I can only select output type in the settings page.) Note that I’m not afraid of tweaking database entries, config settings, etc.

So maybe a good starting point might be; what is the mechanism that outputs audio to the hardware device? Is that liquidsoap?