On this machine, Audacity doesn't have "ALSA Default". It has other ALSA choices, but not that one. And... The ONLY way it will record anything is when it's set to OSS /dev/dsp. In Sound Preferences, all is set to ALSA.
I still don't understand how the recording options can vary SO widely. Different versions of ALSA? Different sound cards? Some set-ups have several choices with alsamixer, and others have only a few.