Mac OS X Microphone Settings
Learn how to check if your microphone is correctly configured, fix the settings if it isn’t.
Note: This guide was updated for OS X El Capitan 10.11.6, but was originally written for OS X Mavericks 10.9.2. You may notice small differences (the only one we've found was in the Apple icon menu, which changed a little bit).
Reset the PRAM
Step 1: Turn off the computer and then turn it back on.
Step 2: Press and hold the Command (⌘), Option, P and R buttons (all together) before the gray screen appears. Hold the buttons until the computer restarts and you hear the start-up sound again.
Step 3: Once done resetting the PRAM you will need to reconfigure the microphone settings. Go back to the beginning of this guide and follow steps 1-9 again to test the mic.