The Eurolive VQ1800D is a professional, active 500-Watt 18" PA subwoofer with built-in stereo crossover. The VQ1800D active subwoofer is ideal for adding serious bottom end to DJ and club rigs. Packed with an incredible array of professional features, these little powerhouses provide lots of low-end punch, with the kind of definition and clarity typically reserved for much larger systems. Instead of operating relatively continuously like Class AB circuits, Class-D amps are either fully on or fully off, significantly reducing power losses given off as heat. Less heat generation means our amps don’t need massive heat sinks and all that unnecessary added weight. Behringer's no compromise design allows VQ Series subwoofers to deliver full power with incredible fidelity all night long. When used in conjunction with switching-mode power supplies, which don’t require huge and heavy transformers, our VQ Series’ Class-D amplifiers provide tremendous punch and superior fidelity. The resulting speaker systems are much lighter, making them easy to transport and set up. This enables us to control the quality, and frankly, make better components. The VQ1800D feature balanced XLR inputs and outputs, as well as balanced XLR Thru jacks for connecting additional enclosures. A Boost Frequency knob targets a frequency between 40 Hz and 90 Hz. Flick the Boost switch to give your selected frequency a +6 dB boost. These subs also feature a High Cut dial to control the upper corner frequency (70 – 150 Hz) for the subwoofer’s amplifier. The High Cut dial does not affect the Thru or Output signals, only the signals directed to the subwoofer. A Level knob controls the Input gain, and the Phase switch reverses output phase to compensate for frequency cancellation between the subwoofer and satellite speakers. LEDs show operational status at a glance, including Power, Signal present and Limit. Features Professional 500-Watt powered subwoofer for PA applications Powerful 18'' long-excursion transducer with high temperature voice coil provides incredibly accurate and pulse-pounding bass Precise reproduction of ultra-low frequencies for "bulletproof" punch and impact State-of-the-art 500-Watt Class-D amplifier with comprehensive over-excursion, thermal and clip limit protection Built-in active stereo crossover provides high-pass filtered outputs for full-range loudspeakers Tunable and switchable Bass Boost plus Phase switch for ultimate low-frequency performance Variable High Cut control for perfect sound alignment Subwoofer Level control to adjust the balance between subwoofer and the full-range speakers Power, Signal and Clip LEDs for perfect monitoring Intelligent limiter for maximum sound performance and woofer protection Internal switch-mode power supply for noise-free audio, superior transient response and very low power consumption Pole socket for mounting with commercial spacer poles Ergonomically shaped handles for easy transport Rugged steel grill for optimal speaker protection