A few weeks back, my headphone jack stopped working properly on my laptop, and I've resorted to a USB sound card that has headphone and microphone ports. However, I've only just now tried it on Kubuntu (12.10), and I've run into a couple problems (well, one is mostly a question).
When I first plugged it in, sounds still played out of the laptop's speakers by default. Naturally, I poked around in the mixer, and found that the device was, in fact, detected, and sound played when I moved the volume slider around (I had "Volume Feedback" on). I then found a "Select Master Channel" option in the Settings menu, and saw I was (apparently) able to set the device controlled by the master volume. I set it to my USB card, and I was able to control the volume with my laptop's audio controls and the mixer tray icon, but all the applications I tested still used the speakers. Does this "Select Master Channel" only deal with the volume control and not the actual default device? In any case, I forced it to work by using the "set-default-sink" command in PulseAudio's pacmd tool, and now almost everything seems to use the USB card correctly, save for the OS itself, Skype, and Steam, for reasons I don't know (they all define their own device preferences? I couldn't figure anything out in their settings though). I'd still like closure on the issue, though. Anyway, it was here that I discovered a second, more important problem...
If I turn the USB device's volume level below 35%, the sound just cuts out, as if it's muted. 35% and up seem to work properly. As it is, 35% is just a bit too loud for my tastes, and it's kind of a pain for anything that doesn't have its own volume control.
As stated before, I'm running Kubuntu 12.10, on a Lenovo IdeaPad Z570. Help would be greatly appreciated!