I had exactly the same problem. I tried USB headsets first but they didn't work and decided to use my older (non-USB) headsets instead. But now mumble busy looped during audio wizard, cpu utilisation was 100% and I had to kill mumble.
Workaround was the same as in comment #5, edit ~/.config/Mumble/Mumble.conf and remove the two lines mentioning usb headset.
This was on lucid (amd64) and mumble 1.2.2-1ubuntu1.
I had exactly the same problem. I tried USB headsets first but they didn't work and decided to use my older (non-USB) headsets instead. But now mumble busy looped during audio wizard, cpu utilisation was 100% and I had to kill mumble.
Workaround was the same as in comment #5, edit ~/.config/ Mumble/ Mumble. conf and remove the two lines mentioning usb headset.
This was on lucid (amd64) and mumble 1.2.2-1ubuntu1.