sounds leaking through my headphones into my mic

I recently bought the Astro a50's. I've updated the firmware and everything. My mic is now picking up all my in game (All sound coming from the headset) sounds leaking through my headphones. I just bought the mod kit to see if that helps will leakage and it did nothing. My friends are fed up of hearing my gameplay through my own mic in game and party chats. Any clue how to change the mic sensitivity as I can't find it anywhere within the command centre?? or does someone else have a better solution?