Why does "Monitor of Built-in Analog Audio" Has no Sound?
I don't know how far you got in this process, so I start from the beginning:
Install pavucontrol:
sudo apt-get install pavucontrol
Launch it:
pavucontrol
- On the Input Devices tab select Show: All input devices
- Check the Volume level and if necessary Unmute the Monitor of Built-in Analog Audio channel by clicking on the little speaker icon.
- Launch Audacity, start recording
- While Audacity is recording: In the pavucontrol Recording tab change the Input Source for Audacity to Monitor of Built-in Analog Audio
Did that help?