To summarize the explanation, the problem was here dmix , which is used by sound cards that do not support hardware mixing (reproduce several different sounds at the same time). Dmix realized in this case a mixing software, to send a single audio stream to the soundcard. The problem is that ALSA dmix plugin does not support the removal of the audio stream from the microphone from the sound card. It is a kind of "virtual soundcard" but only of the output. The solution is to create in / etc / asound.conf a new description for a "virtual soundcard" that uses the sound card directly to the input and output to dmix:
Backup the file / etc / asound.conf :
- Add the definition of pcm.skype "(see code below)
$ Sudo cp / etc / asound.conf / etc / asound.conf.bak
Open / etc / asound.conf with write permission (eg $ sudo gedit / etc / asound.conf) and
- Ensuring replace slave.pcm "dmix" by slave.pcm "skype" in the definition of "pcm." default "
Then save, close and restart ALSA
It remains to relaunch Skype, which should now work correctly.
$ Sudo / etc / init.d / alsa-utils restart