Manufacturers, writers, and salespeople toss around all kinds of numbers and terminology that can be very confusing and misleading. “This $300 shoebox sized sub is flat to 20Hz.� Right, in your dreams! How is that cheap, tiny box and driver going to reproduce a 56 foot wavelength with enough power to be heard? It will not to it. Good bass reproduction requires moving a lot of air and playback at realistic volumes. Remember the rule of needing to move four times the air to go down one octave. Example