I am running windows 7 on my host which has the microphone working just fine but I cannot get the mic to work under any guest (I have tried Ubuntu 10.4 and Windows XP). I am beginning to think that VirtualBox does not support the microphone.
According to this VirtualBox ticket, this problem was fixed under version 3.1.4 of VirtualBox. Are you using 3.1.4 or later?
This could be because of some problem with alsa configuration. Try checking out the current alsa configuration.
open /tmp/foo and check the values for
start the vm again and store the config again
open and look for
This should work for you.
If there is no option for 'Mux capture volume`, I think that u won't be able to record using microphone from ur vm :(