Muffled voice from in game voice chat on xbox

I have an HD pvr and I was informed to buy a 3.5 mm male to 3.5 mm female extension cable. I plugged this into the turtle beach headset I own (pink cable) and plugged that into the computer. I am attempting to record my own voice along with the in game voice chat during call of duty game play that I record. However, when I begin to record, I can hear my voice clearly through the play back but the voices of everyone else is muffled or has a buzzing sound. How do I fix this. I have the 2.0 version of audacity.

As you’ve not mentioned what sort of computer, I’ve moved this to the Recording Techniques section.

Are you able to record the in-game sound, without the microphone, in good quality?
If so, record that, then record your voice-over separately later (like making a voice and music pod cast )