Hello...I am new to the HT world and recently bought a older system off my brother. He had the RCA RT2300 system he bought and has recently upgraded his and gave me this one at a good price. Okay my problem is this...I don't understand how to set up my speakers to get optimum sound. The levels go from -10db to +10db. Can anyone explain to me what this is? Also, I have read on this forum that some people talk about setting the levels to 75db. Is that the master volume setting or what? Please any information on how to set this up would be of great help. Thanks.