The energy-saving Quadral SUB 60 aktiv is packed with herculean power inside, and this is certainly a subwoofer that generates the deepest bass tones with true force that belies its astoundingly compact dimensions. The long-throw bass driver with robust diaphragm delves down into the very lowest registers. This is pure power, paired with superior electronic know-how that effectively protects the output stage unit from overloading.