hooked up to what? a dvd player? pc? if its pc its not going to output 5.1 that way, you will be best to use the discrete inputs on the amp if it has them. 6 outputs from your soundcard into the 6 inputs on the amp. If its your dvd player then go into the dvd player setup to make sure its set to 5.1 output and the output to hdmi audio. Also the source dvd/bd must have a 5.1 track or you will have to use the amps pro-logic decoder to get 5.1 from a stereo track.