The 15" 500W professional active PA subwoofer with built-in stereo crossover. The VQ1500D features balanced XLR inputs and outputs, as well as balanced XLR Thru jacks for connecting additional enclosures. A Boost Frequency knob targets a boost frequency between 40 and 90Hz. Flick the Boost switch to give your selected frequency a +10dB boost. The VQ1500D also has a high cut dial that provides precision control over the upper-corner frequency of the subwoofer’s amplifier. The High Cut dial does not affect the Thru signals, only signals directed to the subwoofer. The signals at the Output sockets are processed through a 100Hz high-pass filter, providing optimized feeds for your full-range satellite speakers. A Level knob controls the input gain, and the Phase switch reverses the 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 input overloads.