It's a miniaturized version of Bose's "Bass Cannon", used in movie theaters and such:
http://www.cardhouse.com/x09/wave.htm
http://www.avsuperstore.com/moreinfo.cfm?id=2843
http://www.audiolat.lv/awcs.htm
Basically, take the tube, shrink the diameter, and wrap it up a few times to pack it into a shelf radio (a really big, flat one at that, more like a tabletop radio).
It does what it's supposed to do: make an average driver produce apparently hefty bass. Nuance? No. Explosions? Sure, good enough.