Used to have the surround decoder II; easy to install and worked fine. The only problem is you need you use the “thick” shieled Powerlink cables. Otherwise, you will have some low frequent humming in the speakers. From the link looks like the Decoder III is a completely new product, pretty expansive too. I sold my decoder II and bought a Beosound Stage. To be honest have almost the same surround effect with the stage compared with my previous Alamndo – 4 speaker + central speaker setup.