An add-on microphone is available to turn existing headphones in to a headset
Article (Product Review)
Audiophiles Like Games, Too: Hands On With Antlion’s Detachable ModMic 4.0 | Tom’s Hardware
From the horse’s mouth
Antlion Audio
My Comments
There are situations where we want to purpose a pair of good headphones like hi-fi-grade headphones to become a stereo headset with microphone. Here, you may want to use these “cans” for gaming or communications and they have a captive cable so you can’t install a microphone cable to use them as a headset. Similarly, you may have a wired stereo headset that has a broken mike but works well as headphones.
Antilion Audio has supplied an add-on boom microphone that clips to an existing pair of headphones using a magnetic clip that you fix to your headphones. The ModMic uses a long microphone cord to connect to your computer which would have to have a separate microphone jack. It can be adjusted to suit best sound pickup as with other boom-capable headsets.
If you deal with a laptop, tablet or other increasing number of devices that uses a four-conductor headset jack, you would need to purchase a headset Y-adaptor from an electronics store so you can use this same jack to connect your headphones and the ModMic to the device. Personally, I would like to see Antilion Audio offer a headset jack adaptor so you can use this mike and your cans with devices that have headset jacks.
At least this is a way to add another usage case to your good headphones whether for gaming or for communications setups that support HD Voice sound quality.