playing radio station with my LG home theater system

Does anyone know if there is a setting on my LG smart blue ray home theater system that will allow the music or sound to play through all speakers at one time? Anotherwords, when I put on a music channel on my television set or if I set the home theater system on FM radio, the sound only comes from the 2 front and center and sub speakers, not from the rear spekers. I would like the sound to come out of all speakers.