New blue ray player to surround sound i already have?

i have a dvd 6 changer with surround sound(sony), and i am thinking of getting a blue ray player and i know the sound is supposed to be better , so my question is , can i buy a blue ray with reciever built in and use my speakers or do i have to go through my dvd player i already have to get theatre sound? i just dont know enough about the blue ray players.