[Otto]

I might actually be willing to do something like that...

Where are you with it right now? Do you have the PC connected to the receiver/preamp? That's the first step. Get REW installed and physicallly connected to the PC, so that it can do a sweep. You will take the line-out of the soundcard, using a stereo cable, to an analog input on your receiver. At that point, you should be able to generate "sounds" to your system via your PC.

Also, connect the SPL meter to the "line-in" (don't use "mic-in") of the soundcard. You will use a stereo plug to the soundcard, and it will have to break out to left and right. You will insert the SPL meter to one side of that (REW defaults to left, so just go in left). At that point, you should be able to measure sounds coming in the mic of the SPL meter (e.g., if you have the "SPL Meter" up on REW, it will jump if you clap your hands in front of the SPL meter).

Let's see if we can get that far, and then see what happens.

I don't suppose you're in Colorado?