My MacBook Pro has headphone and line in ports, as do most laptops produced ever, however don’t plug a microphone into the line in port and expect it to work. It turns out Apple decided that the line in port would be line level only. This means it lacks the amplifier required to handle un-powered audio sources, like a headset with a microphone. OS X will happily attempt to use anything you plug-in to this port but it won’t be loud enough to use.
Apple don’t exactly advertise this anywhere and a quick search shows may people have been caught out by this. It also turns out that the MacBook does have the right hardware but only in the headphone socket. You have the following options.
- Buy an external sound card. Like this one
- Get a 2x 3.5mm TRS to TRRS adapter. Like this one. Have a good look at the photo of the plug both here and on the headset linked to below. That’s the kind you need.
- Use a headset with a single output. Like this one
I bought the SteelSeries adapter linked to above which is why I’ve used SteelSeries links here but many people make the right bits. Find something that suits you.
tl;dr
Recent MacBook’s line in port is useless for a headset. You need either the correct type of headset, an external soundcard or an adapter.