Both have a microphone which you set at the listening position; then a series of test-tones follow for a few minutes which serve both to calibrate the speakers for loudness and distance and to equalize their frequency response, as affected by the room. This isn't to imply that the equalization is anywhere near perfect and results in a totally flat response curve, but there's significant improvement in smoothness. This is one of the very few things that actually can make a difference in sound, rather than just making meaningless claims of sonic superiority.
