I was just given a pair of Apple earbuds with a built-in microphone. When I plug it into my Thunderbolt, it brings up the headset/microphone icon (versus just the headset icon when I connect one without a microphone); however, no one can hear me when I'm using it. Is there some sort of setting somewhere in the menu that I need to configure? Maybe an app I cna download? Or is it simply a faulty headset?