How to Select default audio device in Ubuntu 8.04

I am using plantronics USB headset connected to a laptop with Ubuntu Hardy installed. I can play audio through USB headset using totem movie player after it was changed in System > Preferences > Sound. The problem is Mozilla Firefox is not playing audio through USB headset. Firefox can play audio through the laptop speakers but the sound sucks.

To fix this problem, we need to tell alsa to set the USB headset as the default sound card.

asoundconf list

Here are the list of the sound cards present in the system.

Names of available sound cards:
SB
U0x47f0xc001

The USB headset would be the "U0x47f0xc001", now lets make it the default sound card.

asoundconf set-default-card U0x47f0xc001

Done...

If you want the GUI version of this command, just install it.

sudo apt-get install asoundconf-gtk

To open, go to "System > Preferences > Default Sound Card". Set your default sound card and restart your computer.