Distance
Seriously, how important can this be? You let auto-calibration take care of this for you, or if you’re feeling particularly hands on, you might whip out the tape measure, right? A word of wisdom: don’t underestimate the power of the distance setting in your A/V receiver. Obviously the primary job of the distance setting is setting a delay relative to your other speakers. Note, the distance reported by your receiver’s auto-calibration will be inclusive of any delay caused by signal processing happening inside the subwoofer (EQ, low pass filtering, etc.), which can add several feet to the distance per your tape measure. Above and beyond this, the distance adjustment functions as a phase control of sorts. Adding or subtracting a couple feet from the distance of your subwoofer is a viable way of getting rid of an ugly peak or dip around the crossover point. Again, to make the most out of this tool, one does need the ability to take measurements. Still, who would have ever thought such an innocuous setting could have that kind of power?