The aux port doesn't work when the headset is connected to transmitter

My headphones have worked great for years but, I just got an Xbox and wanted to connect my headphones to my computer wirelessly and through the aux at the same time. (so that I get game audio and can use my computer at the same time) The headphones connect to my computer fine via the wireless transmitter, yet as soon as I connect them to my controller through the aux cord the Xbox audio is muffled and only plays audio through the left ear. (it is not just the Xbox it has this problem with itis anything I attempt to connect to the aux) This should be able to work, and one of the reasons I like steelseries headphones is because they can connect to two devices at once. I also have artics series 7 headphones and they can do this fine.