Speaker System Calibration

[reeltrouble1]

Polkie needs help.

When I first set up my system I just calibrated to 75db using the Rat shack meter and the receiver test tones. So then I add a second 450 sub and Mantis tells me how he sets these up. So I do this and sounds good. But then I buy the Avia disc. They talk about how 85 is the true level for the DD recordings etc. OK, this is very loud I understand, but what is the difference, if I calibrate to 75 or 85? I thought I was just trying to get the same pressure level from each speaker. I mean why not 65? And just turn up to where I like it? If you calibrate to 85 then how do you know where to turn up master volume? Just go to 0 relative on the reciever? Measure somehow with the SPL? I know its about how it sounds to me, but I am trying to understand the theory. Even at 75 the system gets very loud before 0 relative on the reciever. My room is 2970 3/ft, with some large openings.

Help!!!!!!!! I guess I still just do not understand what proper calibration means.

Dang I double posted this, would Admin please remove the first one.

[VR3]

75 DB on my receiver, with Pro Logic test tones isnt very loud, and it would max my receiver out by setting it up this way. I calibrated mine to 65db on -40 on the receiver. It blends perfect to me. You set the master volume on what you usually listen to it on.