Mac OS X Microphone Settings
Follow the steps below to determine what the problem is and hopefully fix it:
Step 1: Click the Apple icon present in the top left corner of the screen. A menu will appear as shown in the image below:
Step 2: Click System Preferences.
Step 3: Under system preferences select Sound either by clicking it or by searching for it in the search text box.
Step 4: Under Sound select the Input tab.
Step 5: the list of recording devices will appear. Make sure that the “Internal Microphone” is selected. Try speaking into your microphone, and look for blue bars moving beside Input Level while you talk (see screenshot).
Step 6: If the blue bars are rising while you are speaking that means your microphone is properly configured (what to do if my microphone still isn’t working, even though you say it’s properly configured?)
Step 7: If the blue bars are not rising while you are speaking into the mic, keep following the instructions.
Step 8: Drag the slider all the way to the right, to set the max volume.
Step 9: Now check again if you see blue bars rising when you talk into the microphone: if you do, your mic is now properly configured. If the microphone still does not work, keep following the instructions.
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.
Create a New Account
Create a new account from System Preferences, User & Groups pane as shown in the image below:
Log out and then log in again with the new account. You will need to log out from the current account instead of Fast User Switching. Once you log in with the new account try and test the microphone (follow steps 1-9).
If it works then the problem is with your user account. If it still does not work then the issue is either with the hardware, or there is still a problem with your OS that this guide did not cover (we try but we can’t get it all). Try the Apple Support Communities for further assistance.
What To Do If Your Microphone Is Correctly Configured (Blue Bars Were Moving When You’re Talking Into The Mic) But It Still Isn’t Working In Some Program?
If you could see blue bars moving when talking into the microphone then it means that it is configured correctly, and that your Mac can "hear it". To verify that use our mic test and see that the browser is indeed receiving the input from your mic.
The program, however is not configured the right way. It might be listening to the wrong microphone, or maybe its volume is too low. Try playing with that program's settings, or contact the their support staff if you're not sure how or need help.