I bought a Digi+ I/O (eyes open about its limitations) because it was an inexpensive experiment. I have a Pi4 with my USB turntable attached and stream to my Sonos with Icecast. This works fine. The Digi I/O was an experiment to get my CD player into the setup. This works fine IF the player is playing something before another darkice instance is started using the I/O input. Once the CD player stops or is tuned off then darkice exits with an I/O error. If darkice is started with no input then it exits similarly. All as expected.
I believe a DSP solution is what I now need to get an input which won't error out with no signal but just record silence.
Is the DAC+ DSP what I need and how do I permanently set the SPDIF input to mix with the Pi Audio?