Make sure to backup the file before modifying, just in case
cd /usr/share/pulseaudio/alsa-mixer/paths
sudo cp analog-input-front-mic.conf analog-input-front-mic.conf.bak
sudo gedit analog-input-front-mic.conf
Note: if on a laptop, the file is probably analog-input-internal-mic.conf and analog-input-headset-mic.conf. The one above is for Desktops, specifically the front jack.