Your SHIELD Controller supports headphones and headsets.
Plug the headphones (3-pin) or headset (4-pin) into the 3.5-mm jack on the bottom of the controller. When headphones are used, the internal microphone on the controller is available for voice search and chat. When a headset is used, the headset microphone is used for voice search and chat.
The headset jack provides independent volume control from your Android device and maintains your previous headset volume level the next time you use your headset.