I recently bought a new headphones, which have two jacks; One for microphone and one for headphones. My Macbook Air only has one "hole", which is for the entire headset. I bought a reduction. The problem is, neither my Mac nor other computers recognize the external microphone I have wired up through the reduction, not even if I plug the microphone jack itself to the headset hole. (Headphones play sound even if its wired thru the reduction, so the reduction itself is not broken anyway.) I've tried it on several computers and systems, but I'm writing this here because I have a Mac after all.
Hope you can tell me some info on that problem, thanks.