The powerful Blackline S218+ sub-bass system has been designed to be used with large scale Blackline F12+ and F15+ systems to extend and increase the total low frequency output power. It can also be used as the low frequency section of a bi-amped or tri-amped H3+ system. The S218+ provides good bass punch with extended sub-bass output from two new, long-excursion, 18-inch (460mm)/ 4-inch (100mm) voice coil drivers with water resistant cones and triple roll surrounds. The S218+ must be electronically crossed over with the M3+, DX1 or equivalent Electronic Controller.