how to use laptop mic even when trrs headphones are connected [duplicate]

Use any stereo 3.5mm to 3.5mm plug. Out that in your computer and the plug in the headphones to the adapter. The stereo adapter will not see the mic, so the computer will not see the mic.

You can get these 6 inches (15cm) long or so, maybe even shorter. If you want just an adapter without a cord, get a stereo splitter. Search for “headphone splitter” and you can find plenty under $5.

As long as you don't plug the earbuds in all the way, you can still use the built-in mic. The catch is that you'll only get audio in one ear of the earbuds.

You should be able to bypass the headset mic and use the Mac's internal mic if you select internal mic (double click it to select it) on the sound input preference tab and then plug in your headset.

This troubleshooting procedure is detailed on apples website at: https://support.apple.com/kb/PH25716?locale=en_US&viewlocale=en_US