how to configure for surround sound on mbp

I don't really know what I am doing. I want to get better sound from my surround sound via sony receiver via my mbp. Should I use the audio MIDI setup? My receiver is hooked up with a RCA audio cord. I have 4 little sony speakers 2 in the rear and 2 in the front with a center speaker. I don't even know what type of surround sound or how many channels. I am trying to educate myself about this stuff but there is a ton of info out there. I just want to improve the sound when I watch movies. What should I do? Thanks for your help.


Beth

OK, startling discovery. The sound sounds great when the tv if OFF. When I turn the tv on I can hear this buzzing sound that I have been trying to get rid of. What is that and how can I make it stop? I noticed the other night that when the scene changes sometimes the buzz would be louder or quieter. It is driving me crazing like a bug in my ear.

beth

Oh yeah. I think the black box on the floor holding the dog toy basket is a sony subwoofer. And the buzzing is the loudest out of the middle speaker.