Newbie question, In setting up my new Onkyo 601 receiver, I set speaker size and number, distance, crossover, db etc. no problem. The speakers sound fine on the test menu, but with DVD, VHS and TV sources, I get good front sound but no sound at all from the two surround speakers. I've tried both DTS and DOLBY on the DVD sound setup. I'm using composite cables from VHS and DVD. I've reviewed the receiver and DVD setup menus 'til I know them by heart and see nothing amiss. What am I missing?