Our BP-SD21, The Sub Engine has the low frequency output to match its eye-catching appearance. It boasts folded-horn output from a box one half the size of one of our WH folded horns. The 21" low frequency driver has the lowest power compression we have ever measured thanks to its massive magnet structure and huge 6" diameter voice coil. Each BP-SD21 is capable of handling 2,000 Watts program power. This speaker has been turning heads with the output equal to a typical double 18" box, but it is nearly as small as a usual single 18" box.
Also available, the BP-SD18 Sub Engine Jr., an impressive 18" version of the same concept.