Option-Click Sound Menu to Change Input Source
If you want to quickly change your sound input device, by far the fastest and simplest way to do so is to Option-Click the Sound menu icon at the top of your screen, which enables an alternate pull-down menu including a list of clearly labeled and named available input devices. From this menu, select your new input source, whether that’s an external microphone, bluetooth device, or whatever, and it will immediately be set as the universal input to the Mac.
This is so much faster than going the standard route of opening System Preferences and adjusting the microphone and line-in audio sources through the “Input” settings, and since it can be done from anywhere and without changing the applications, it’s not only faster but just more efficient. The only real downside to this approach is that you won’t see the microphone sensitivity indicator that you do through System Preferences, so if you need to double-check that or to adjust the line-in volume level you will need to do that through the general Sound Input preferences.
Of course, you can also toggle the input back to the default setting by option+clicking the menu again and choosing “Internal microphone” to set it back to the built-in mic.
This is an excellent trick for audio geeks or for any situation where quickly changing where audio is coming from is a necessity, whether you’re trying to use an external microphone, or any third party audio-in source. This sound trick has been around in Mac OS X for quite some time and remains supported available in all current versions. Enjoy!