Internal Mic Doesn't Work After High Sierra Upgrade

I recently upgraded my MBP (Late 2013, MBP 11,1) to High Sierra.

For some reason the internal microphone no longer hears speech after the upgrade. I have the input volume on the mic at maximum however I do not see anything on the "Input Level" bar when I talk. The mic does appear to be working at some level - if I tap the mousepad hard or tap my finger over the location of the mic I am able to see activity on the input level bar.

Does anyone have a fix for this issue (I have seen a few other posts complaining of the same thing). Is there some type of bug in High Sierra?