Internal microphone is not working

I've had my macbook air for a while already and I only realize now that my mic isn't working.

I've only needed to use the mic when I was using facetime so far. And I never have a problem then.

However when i tried to skype I noticed my mic wasn't working. That when I also tried to record a video using my macbook and it didn't work either

When I go to sound, it seems t recognize the internal mic as it shows up, but it doesn't register any sound at the input level. However, if have this open when I am facetiming the input level seems to register sounds then.

I don't understand why my mic is only working when I am using facetime. I think at some point a long time in the beginning it might have worked but maybe after a update it didnt?

Can somebody help me fix this? Or anyone with similar problems?