I have a USB sound card that has an audio out and a microphone in. That sound card works fine - a small microphone records fine and a small speaker plays sound back fine.
However, I now have an additional USB microphone (a PS eye) that plugs into a differnt USB port. So my RPI now has two microphone inputs: one from my sound card and one from the PS Eye. My /etc/modprobe.d/alsa-base.conf has these lines:
options snd-usb-audio index=0 options snd-bcm2835 index=1
I have not done any additional configuration for the PS Eye, all I did was plug it in. So, how can I tell my RPI to use the microphone in the PSEye instead of the sound card microphone? I still want to use the sound card for audio out.