As I recommend these RF attenuators with the SPDIF output Hiface & I am getting a lot of questions about these devices, I've re-written & re-posted my short write-up about these attenuators & how they work. It gives you all the information about how they work & where to purchase them. Essentially they are small adapters that will attach at either end of your SPDIF cable & will improve the sound.  Read more about them here .