This might not be helpful, but since no one else has responded, I figure it's better than no answer.
I think you may find that a high quality Bluetooth headset will serve your needs without all the extra costs and hassle of extraneous software and hardware setup to fake 7.1. If you get a Bluetooth set, you can just sync it to the laptop without any extra external devices (I assume your laptop has BT). Then select your audio device as the BT device and video will continue to transmit over HDMI. Besides,why bother with 7.1 surround sound when it will only be 2.0 when it hits your ears? Something to consider.