Apple - Macbook Pro Audio Input Not Working With Microphone
Mac laptops have not supported a non-powered microphone input for years.
The input you see is a "line-in" input that requires more input signal level than a passive (non-powered) microphone can deliver.
You will need an additional pre-amp or active mic (a microphone with phantom power will suffice).
Actually, if you plug in an TRRS plug (the one with three rings on it) into the headphone jack, your Sound menu will switch from "internal mic" to "external mic" and you don't need a powered headset. So if you have a headset with two plugs, you'll need a combiner Y-adapter for that. They're about $4.
Edit: the TRRS plugs come on headsets like the iPhone headset as well. Those work fine.
If you microphone has a physical mute switch, this can confound the Mac a bit. If you leave it muted, it seems either the port or the OS eventually decide there is no mic there and switch back to the internal/built-in mic.
When this happens, the only actions that work for me to get the mic recognized again are to:
- Open the mute switch
- Unplug from the port
- Plug back in again