Ubuntu – External microphone not working

gnome-volume-control does not recognise external hardware. My headphones work nonetheless, but an external microphone does not. External microphones used to work, but at times were temperamental – I would have to login or logout with or without microphone plugged in.

I am running Ubuntu 10.04 LTS (Lucid Lynx) on an mSi U100 wind notebook with one Intel soundcard and trying to use a jack microphone which has worked previously. USB microphones have also been problematic.

I have done the basics:

• Installed upgrades.
• Checked nothing is muted.
• Looked for the device on gnome-volume-control.
• Tried using a different microphone that works on a friends computer.
• Tested my microphone works when using a different computer.
• Checked my soundcard can be seen (cat /proc/asound/cards).

I have done more complicated things:

• I have tried playing around with settings in alsamixer. Nothing is
  muted. I can adjust "mic" and "internal mic" regardless of whether
  an external microphone is plugged in. I have the choice of input
  source from "mic", "front mic", "line" and "CD". I've played around
  changing this and it hasn't helped. I only have one CAPTURE option.

  • In gnome-sound-recorder I have the choice of line, microphone 1 and microphone 2. I have played around changing this option. None of
    these pick up sound from the external microphone. Microphone 2 is the
    microphone on my laptop which is bad quality.

  • In gnome-sound-recorder I have the choice of different profiles, and changing this has not helped either.

  • I have looked at gstreamer-properties but none of that seemed helpful.

I don't know if there a way to check if these external devices are being picked up. I would like to make an external microphone work. Please help!