Simply plug in the USB and go to System > Preferences > Sound. Select 'USB Audio' in 'Sound Events' and 'Music and Movies' and click 'Test'. A test tone should confirm that it's working.
There is a catch. Although tests are ok, Ubuntu players (VLC, Totem, etc.) keeps using the PC loudspeaker instead of USB Audio. To fix this the following steps can be performed to set the default sound device:
- Open Terminal from Applications > Accessories
- run the command 'sudo asoundconf list', you need to enter admin password. On my IBMT23 I got back:
Names of available sound cards:
- Then run 'sudo asoundconf set-default-card PCM2702' followed by a reboot to test.
The same procedures can be used for other Ubuntu/Linux compatible DAC such as SoundBlaster Live!