Low frequencies can occur in nature, waterfalls, earthquakes and the like. Here is a writeup, with photos, of a multiple rotary subwoofer installation for the N

Low frequencies can occur in nature, waterfalls, earthquakes and the like. Here is a writeup, with photos, of a multiple rotary subwoofer installation for the Niagra Falls Fury show about the creation of Niagara falls. http://www.rotarywoofer.com/niagara%20fury%20index.html http://www.rotarywoofer.com/niagara%20fury%20index.html