As
@KGIII said, open Pulse's mixer as the first thing (and hope it's as simple as that).
Go to the "Input" tab (not "Recording") and check if your device is listed. If it is, make sure it is selected as the default/fallback one. Also, try turning the volume to max and snapping your fingers near your mic to see if the level meter shows a response. If not, your mic may be a dud or there's a conflicting device or a myriad of more subtle problems like device indexing (which you can make static by adding a rule in /etc/modprobe.d/ for example).
Or, it may be a simple user-level issue solved by editing ~/.asoundrc. More information is need, for example, is your mic USB? How many capture devices do you have, etc. Let's try to narrow it down. FYI: I'm not a Linus sound expert, but I'll try to help. More importantly, anyone who can help will need this (or part of) information:
What's your basic setup?
What are you trying to do?
What do you mean "a crack was heard?" because that is normal for an analogue mic when plugged in/switched on if sharing a card with your playback.
Also, dumb question, but if analogue, make sure it's in mic and not Line In.
What's the output of:
$ arecord --list-devices
# cat /proc/asound/cards
# cat /proc/asound/devices
# grep snd /proc/asound/modules
