Thanks. Can you edit /usr/share/alsa/cards/USB-Audio.conf, scroll down to the "USB-Audio.pcm.iec958_device" section and add the following line:
"Sennheiser USB headset" 999
(including quotes)
...just above the similar "Logitech USB Headset" 999 line. Notice that your headset is spelled with a lowercase h.
Save the file and reboot to test. If you can confirm this resolves your problem, I will be able to submit the attached patch, that makes this the default for Ubuntu and upstream ALSA in the future.
Thanks. Can you edit /usr/share/ alsa/cards/ USB-Audio. conf, scroll down to the "USB-Audio. pcm.iec958_ device" section and add the following line:
"Sennheiser USB headset" 999
(including quotes)
...just above the similar "Logitech USB Headset" 999 line. Notice that your headset is spelled with a lowercase h.
Save the file and reboot to test. If you can confirm this resolves your problem, I will be able to submit the attached patch, that makes this the default for Ubuntu and upstream ALSA in the future.