I have a Plantronics USB headset and am running Kubuntu 18.04 on a laptop.
When plugging it in, it immediately shows up in audio device and also selects it as the default.
Even so, the sound still comes through the laptop speakers.
The USB ID is 047f:c025, if that helps anything.
How can I troubleshoot and fix the problem?
I was having a very similar issue, though in my case the device ID is 047f:c023 (Plantronics C310-M). I was able to work around the problem by disabling all other sound devices.
For example, if you are using the Pulse Audio Volume Control, click the Configuration tab and choose Off for all the other devices.
If anyone figures out a better solution, I would love to hear it.
