The fundamental difference between 5.1 and 7.1 surround sound is the number of speakers. A 5.1 system includes front left, front right, center, surround left, surround right, and a subwoofer. A 7.1 system adds placed behind the listening position, increasing the sense of immersion and creating a more seamless soundfield.
Look for kits that include a remote control or a physical button interface. This allows you to adjust the master volume, fine-tune individual channel gains, switch input modes, and select equalizer presets. How to Set Up and Wire Your Decoder Kit 7.1 dts dolby digital decoder kit