I am presently having trouble getting Ardour (and Audacity for that matter) to recognize any sort of input. I previously had Audacity working in 7.04 but have had problems since I installed 7.10.
The problem I am having is that none of the available input selections will record anything. I tried plugging my guitar into both the mic and the line in channels. According to the Ardour manual, I opened up the alsa mixer, but mic was the only option for capture. The same problems exist when I try to use Audacity.
this is then no Ardour specific problem.
Try to get some overall knowledge about audio recording, because it’s hard for someone to get a starting point to help you.
First thing is that you cannot just plug a guitar into a soundcard, because the output of a guitar is very low.
Ah, I overread that you previously got it working… hm, it really depends on your soundcard which channel you have to select in Ardour.
The rough signal flow is about this:
guitar -> amp or something -> lineout or mic -> soundcard -> alsamixerchannel -> Ardour
If you set everything right before the soundcard, you just have to make sure that the recording channel is enabled and turned up in alsamixer, then just find the right input channel in Ardour.
If alsamixer really only shows one (wrong) channel for input, then it might be a problem with ubuntu that is hard to fix in this forum.