I've been running a dedicated machine with ALSA loopback, feeding darkice on the capture side and (currently) using mplayer to provide audio on the playback side. I've seen sporadic hangs for a couple of years on this setup, but recently with the switch to mplayer I have additional information that points more to ALSA than the other applications.
When the audio hangs, mplayer prints a continuous stream of: "Audio device got stuck!"
The only way to "unstick" the audio stream is to terminate and restart mplayer. Restarting darkice does not fix the stuck stream. There is no pulseaudio on this sytem.
What would be the next steps to debug this setup? It's shown up on two entirely different installs at this point (Ubuntu 14.04 and Debian 9).
Thanks!