When you try to connect an external microphone you may run into the problem that your Mac does not recognize the microphone. This happened to me when I tried to connect my Rode VideoMicro to my Mac. The problem is that there are different standards for audio jacks.
In this post, I will explain the different standards and what is needed to make the external microphone work with your Mac.
TS vs TRS vs TRRS
The audio input on your Mac is of type TRRS and the plug from the microphone is of type TRS. What does that mean? In the figure below you see three plugs of type TS (tip sleeve), TRS (tip ring sleeve), and type TRRS (tip ring ring sleeve).
Type TS allows for mono sound to be transmitted. The tip is for the audio signal and the sleeve is the ground.
Type TRS allows for stereo sound to be transmitted. Again the sleeve is for the ground, the tip is for the left channel, and the ring in between is for the right channel. The plug on your microphone is of this type.
Type TRRS adds an extra ring for microphone input. This is the type of audio headset with a microphone and therefore the type of audio jack on the Mac and other computers.
Now the external microphone is most likely designed for a camera. Stereo sound is always transmitted in one direction, from the microphone to the camera. A TRS connection makes perfect sense here. So cameras and microphones that are meant for a camera have a TRS connection. The audio input on your Mac has a TRRS connection so you just need to get a TRS to TRRS converter cable right?
Not so fast. You didn't think it was going to be that easy did you?
CTIA vs OMTP
For maximum confusion, there are two standards for TRRS jacks. In the image below you see two TRRS plugs, one for the CTIA standard and one for the OMTP standard. As you can see the two standards have ground and microphone flipped.
For a Mac you need a TRRS connection following the CTIA standard, so you need to be careful when you are shopping for a TRS to TRRS patch cable. If you don't want to be bothered about it, the Rode SC7 works. Put the black plug in your microphone and the grey one in your Mac and you are good to go.
I hope this post saves you the time that I lost and the frustration that I experienced when I first tried to connect my external microphone to my Mac.