boom

http://www.velodyne.com/products/manuals/63-ULD1518.pdf
http://srforums.prosoundweb.com/index.php/t/9524/0/
http://www.livesoundint.com/archives/2002/janfeb/bass/bass.php
http://www.prosoundweb.com/article/lsp_documentation_page_drawings_photos_specs_and_more/
http://www.fullcompass.com/common/files/3433-TSW124%20Turbosound%20specs.pdf
http://www.tritechlightandsound.com/BassTech%207%27s.html
http://www.licht-geluid.nl/forum/live-forum/3556-lab-hoorn-subwoofer.html