I can confirm this bug. I'm using a RolandED UA-30 external with no
internal card. The card doesn't work at all in firefox or other software
which assumes alsa's default, and I've only gotten it working in mplayer
by specifying the card in ~/.mplayer/config.
Strongly suggest adding a panel to set
Please see bug 31109, bug 46996, and bug 46998. There's no way
[currently] that we can dynamically assign these indices. Some people
want onboard to override external sound cards; some people want the
opposite.
Luckily there's a workaround that doesn't require you to know the
innards of asoundrc
