This is a note to myself because I will forget how to do this. This is in Ubuntu on an HP Pavilion dv4.
In a terminal, run ‘alsamixer’.
Towards the bottom right, there are two items labeled ‘Digital’.
For the system to recognize the built in microphone, the first needs to be set to ‘Digital’ and the second to ‘Analog I’. For the system to recognize the audio input jack on the front, they must both be ‘Analog I’.
Then, open System > Preferences > Sound, or double-click on the volume in the task-bar and open preferences. Under the ‘Input’ tab, switch to whichever device shows some input levels. For the external, this is ‘Microphone 2′ but not ‘Microphone 1′. Adjust gain as necessary.
Then you can run qarecord to record wav files.
Now all I need is something that can play LP records and I’ll be in business.