I'm trying to record output (that what I can hear) with Audacity, but no sound recorded. I have found some instructions how to record with Pulseaudio, but I have only Alsa. I can't see any option in alsamixer or audacity. Is it possible? Thanks!
This depends highly on your sound card. To do so without some kind of software intervention would require a "full duplex" sound card.
Basically look in ALSA Mixer (
Many, many computers do not have full duplex cards, in addition the channels may be named something else.
There are some options, if you do not have a full duplex card. This site should get you started, but recording the playing sound, generally requires a better then average sound card.