Built in mic doesn't calibrate

Hey,

I have a problem on my macbook, I can't calibrate my mic.
I slide the calibration bar to where I want it and I test the commands and it works fine, but when I click done and click back on the calibrate button the indicator has slided all the way back to the right.

Does anyone have a solution for this, I've searched the net and found one or two threads with this topic but they were very vague and not helpfull.

Thanks