Except when it doesn't. So I've been sitting here for the last two hours trying to figure out why, when I plug the tape deck into the line-in jack, start the tape, and press record, I don't get anything to record, even though I can hear the sound coming out of the computer's speakers, and even though things have worked in the past.
So after much searching, playing with JACK, tearing out my hair, yelling at the cats, etc., I finally found an appropriate post in Ubuntu forums. Note particularly the phrase “I had the Capture volume down.” Turns out I haven't done any sound recording since I upgraded to 7.10. Does Ubuntu automagically reset defaults when you upgrade? Anyway, following this post, I opened up the gnome-volume-control, clicked on Edit=>Preferences, clicked on line-in capture, and hit record.
OK, go back to the preferences menu. Look down. See an unchecked box labeled Capture. Click that.
Sigh. But now the main gnome-volume-control panel has a tab on it that says “Recording.” Click on that. Up pops a panel that says “Capture,” with the Microphone symbol muted. Click that. Bring the capture volume up to full. Record.
HOW DID THIS HAPPEN? I had it all working before, you know, which meant that all those appropriate boxes were checked and buttons were pushed. AGGGH! Are there little elves running around my computer arbitrarily turning things on and off?
Well, anyway, I got it working, and this here post will remind me of it the next time it happens.