Razer Kraken Headset Back Port issues

Hi all

I recently bought a new Razer Kraken headset and when I plug it into the back port of my computer (using 2 to 1 adapter that came with it), the sound sounds muffled, or as if its further away than it is, however it doesn't do this in the front port. Would anyone know why? (for some reason my mic only picks up audio from my headphones when its in the front port, not the back, so thats why I can't just have it in the front)

Thanks