5) Internal microphone
00:1b.0 Audio device: Intel Corporation 5 Series/3400 Series Chipset High Definition Audio (rev 06)
The internal microphone does not work after a default install. Append the line “options snd-hda-intel model=dell-s14” to file /etc/modprobe.d/alsa-base.conf, reboot and adjust the mixer levels. Thanks to lidex on UbuntuForums: