Features Active PA Sub Woofer Features: 15 x DSP presets with 4 selectable cardioid setups and 7 selectable crossover frequencies (80-120Hz), prepared for mounting of casters, 3 x corner handles, 2 x threaded flange (M20) Woofer magnet: Neodymium Protection circuits: short circuit, RMS speaker limiter, DSP-based "look ahead" limiter, over-current, RMS power supply limiter Controls: ground lift, Power, Gain, DSP presets, DSP/ Gain enable Description Product Description The LD Systems DDQ Sub 18 is a powerful active subwoofer with digital signal processing for demanding PA applications. It is precisely adapted for combination with the full-range speakers of the DDQ Series and is equally suitable for use with tops made by other manufacturers. The compact bass-reflex design is loaded with an 18" FaitalPRO bass speaker that has a 4" voice coil and a neodymium magnet driven by two 700-watt Hypex Class D power amplifier modules with a highly efficient switching power supply with a total output of 1400 watts RMS. The DDQ Sub 18 attains a maximum sound-level pressure of 134 dB with a frequency response curve of 30 - 120 Hz. The Sharc DSP programmed especially for the DDQ subwoofers ensures distortion-free and reliable operation even at maximum volume levels with a 1ms look ahead limiter, frequency and phase correction, as well as all protection circuits, and has a large dynamic range of 127dB/113 dB (ADC/DAC). Seven DSP Presets permit selectable crossover frequencies between 80 and 120Hz. Eight additional presets make it possible to realize cardioid configurations of 2 or 3 subwoofers, whereby it is possible to attain rear attenuation of up to 20dB. In addition to XLR inputs and outputs, the DDQ Sub 18 has a separate mono output with a 100Hz high-pass filter. Additional features are LED function indicators and a ground lift switch; the volume and preset controls can be deactivated to prevent inadvertent adjustment. The cabinet of the DDQ Sub 18 is made of 18mm thick multiplex with an extremely durable polyurethane finish. It is equipped with two M20 threaded flanges and ergonomic handles and is prepared for mounting of casters.