Anybody feel like dumbing down the conversation for somebody who doesn't understand all the technical jargon.

I'll have a go at this and see what I can do. My beef is that I've been unable to find a decent FAQ out there to explain all this garbage.

The core goal here is to have a tool that tells you the frequency response of your system, which is to say, which shows you where your system isn't flat. The graphs produced by SpectraRTA and other such programs have frequency on the X axis and loudness on the Y axis, and then they make frequency sweeps from your sound card, measuring them with the microphone.

Of course, just like speakers, microphones aren't flat either. Thus, good mikes come with a "calibration curve" telling you which frequencies they tend to get low or high. SpectraRTA tries to correct for this.

Then, you're supposed to tweak your equalizer to fix this. Tony has a nice entry in the RioCar FAQ about Q parameters and all that. Basically, you look at the the graph given by SpectraRTA, you make a bunch of tweaks to your equalization settings, then you repeat. Ad nauseum.

Other terms I've seen pop up here:

Warble tones: if you use a "pure" sine wave, this might set up resonations in your car which are louder than what the speaker is actually putting out, causing you to over-compensate when you tweak the equalizer. Warble tones take the frequency of a pure sine wave and move it up and down, maybe five times a second. This, in theory, helps you get the "true" frequency response of your system.

Pink noise / white noise: There's a nice web page that explains these terms. Roughly speaking, pink noise has the same amount of "energy" at every frequency in the audible spectrum.
You can also use pink noise to test for system flatness, although frequency sweeps seem to be better for measurement.