Cory K. wrote:
  Stephen Doonan wrote:
  Audacity uses PortAudio, not PulseAudio, right?
Two different things,
 which only adds to the confusion (in my mind). :-) 
 I think it depends on your distro or how you've compiled it. In Ubuntu,
 it uses the PulseAudio output by default.
 -Cory K. 
But Audacity uses PortAudio for input (right?) and that is where
PulseAudio was causing problems. Disabling PulseAudio in Ubuntu, in both
System-->Preferences-->Sound and System-->Preferences-->Sessions, solved
the problems I was having.
-Steve