You need 4 sets of twin RCA (Phono) male to 3-poles minijack. Plug the four sets of minijack to be back of the Gigaworks and 8 phono to the back of your AV receiver (Pre-Amp Out). Lime = Front L/R, Orange = Cen/Sub, Black = Rear L/R, Grey = Side L/R
Alternatively, cut the phono end of the 7 speakers, which gives you two strain of wires, screw the wires to the back of the AV unit (Speaker out). And use RCA to minijack. Plug the minijack end to the Orange (Cen/Sub) at the back of your Gigaworks and the RCA to the AV Pre-Amp Out Sub. Make sure you check your AV's RMS wattage and Impendence. Otherwise you might blow your speakers.