Robert, welcome and an appreciation for your service in law enforcement. You should generally rely on the settings arrived at by EzSet/EQ, but a manual setting for a high pass filter to the subs is available on the 645. This rolls off the frequencies delivered to the sub below certain frequencies(30Hz, 25Hz, 20Hz, etc.)depending(somewhat simplistically)on their cone sizes. This is to keep ultra-low frequencies that the sub supposedly couldn't handle well out of the way. I'd forget it or just set it at the highest size. Oh, and yes, Micah's theories suck(just kidding, Micah!).
