I have two Macs on the desk and want to use one set of microphone/speakers with both. One machine, a Mac mini, has a Focusrite audio interface (Scarlett 8i6, love it) connected by USB-C and that has an XLR microphone and powered stereo speakers connected. I want output from a nearby MacBook Pro to play on the main speakers (not its internal speakers) and to send microphone output from the audio interface to the MBP as input (instead of using internal microphone).
No problem getting output. A simple stereo - double TS (mono) cable lets me connect it to the Focusrite box as one of the inputs. I can mix levels in the Focusrite application, plays on main speaker outputs. Sounds good.
Microphone output from the Focusrite is mono. A TS-TS cable connects the output to the mic input of the splitter cable. Doesn't work!
Here's the wiring of my splitter cable - it follows "iPhone headphone" in the picture. Output cable, plugged into the headphone jack of the splitter, follows "Standard stereo headphone". Ignore "iPod AV Cable", it just happens to be in the picture:
That's verified by meter testing. As soon as this cable is connected MBP lets me set output to "External Headphones". However I never get the option "External Microphone".
The output from the microphone is good, if I connect it to the microphone input of a nearby PC no issues at all, good levels, clear audio from microphone. I just never get the option to select it on the MBP.
Just what is the input on a MBP 15,1 for if not for this?
Is the Mac doing some tricky resistance or 1-wire interrogation of the connected device and refusing to allow anything but a device that gives the right answer?
If I had a set of TRRS AirPods with included microphone would that microphone work? Does anything work as input on MBP?
I really don't want to have to use another USB interface for this.