A found a very handy little iPhone app that allows you to do testing and analysis of sound systems. Basically, it's a light-weight version of SMAART and other calibration software packages that you would normally run on a laptop. I simply plugged my iPhone output jack into the sound system and then let it play a series of test tones and then it listened with the iPhones mic. I e-mailed the data set to myself and made a quick graph with google. Bingo.
Why is this useful? Because I can use it to adjust the equalizer in the sound system to get a "flatter" response curve. For example, I see here there is a peak at about 440 Hz. I was aware it was near there, but I had thought it was more like 360 Hz. This is great, I can simply tone that frequency down a little. See?
Other problems, like the general low-performance in low frequency, is nothing I can correct with the current speakers. Still, an interesting exercise.
And yes, you could totally use this to test/calibrate a home stereo.