Every time I boot the microphone is muted. I want it to be unmuted instead. Of course I can do it by 6 easy steps every time:

1. press sound icon in the upper right of the screen.
2. press "Sound settings..." item in the bottom.
3. wait about 10 seconds until a window loads.
4. switch to input tab.
5. uncheck "Mute" checkbox near a microphone icon.
6. close the window.

But I want it to be unmuted by default.

I guess that in linux world this should be changing 0 to 1 in some line in some configuration file, but I don't really know, where is this line located.