This was a demonstration built by graduate students at the University of Wisconsin -Madison in 2011. It's purpose was to be physically large so elementary school kids could look inside while it was running and illustrate the how a speaker works on a grand scale (hence a transparent cone). Although powerful, it was not designed to be competitive with state of the art sub woofer systems or be high audio quality. Documentation of the build process may be found at: http://ludoislabs.com/giant-speaker/