KLA181 18-inch Active Line Array Subwoofer Summary description: A portable self-powered subwoofer system with one 18-inch driver in a lightweight birch plywood enclosure designed for deployment either on the ground or flown as part of a KLA line array system. Drivers: The subwoofer system shall incorporate one 18-inch (457 mm) low-frequency cone transducer. Enclosure: The subwoofer system shall be housed in an enclosure constructed of birch plywood. The enclosure shall be finished with textured paint in either black or white. The front of the enclosure shall be protected with a 16-gauge steel grille that is powder-coated in black or white. The rear of the enclosure shall have a panel for the connectors, switches, and controls of the amplifier module. The rear of the enclosure shall have four sets of mount points, one at each corner, that accept optional casters. The left and right sides of the enclosure shall each have a rigging plate and two handles. The top of the enclosure shall be equipped with four integrated suspension points for use with M10 eyebolts. The top of the enclosure shall also have feet cups for stacking, and a threaded M20 pole receptacle (compliant with EIA 636 Standard) for an included threaded speaker pole. The bottom of the enclosure shall have slip-resistant feet that nest into alignment receptacles (feet cups) on the top of other KLA181 and KLA12 enclosures. The top of the enclosure shall be equipped with integrated SOLO Rigging System fittings that enable the enclosure to lock either to the bottom of another KLA181 or to a KLA AF12 Array Frame for flown deployment. The bottom of the enclosure shall be equipped with integrated SOLO Rigging System fittings that enable locking with another KLA181 or a KLA12. Electronics type and features: The subwoofer system shall incorporate a Class D amplifier. The amplifier shall have an output power of 1000 watts continuous. The subwoofer system shall incorporate circuitry enabling the following digital signal processing (DSP) functions: - Digital Extension and Excursion Processing (DEEP), a non-distorting low-frequency EQ circuit that provides increased low-frequency extension without distortion or over-excursion; - Intrinsic Correction, which evens the dispersion of energy throughout the physical listening area of the loudspeaker. I/O and connectors: The subwoofer system shall have the following input and output connections: - LINE IN shall be via a female 3-pin XLR jack. When the connection is balanced, the input shall have an impedance of 40 kilohms. When the connection is unbalanced, the input shall have an impedance of 20 kilohms. - LINE OUT shall be via a male 3-pin XLR jack providing balanced full-range line-level output of the signal input into LINE IN; - REMOTE GAIN connection shall be via a 3-pin "Euro" jack; - AC IN connection shall be a blue locking powerCON® power connector keyed for input; - AC OUT connection shall be a gray locking powerCON power connector keyed for output. Controls and indicators: The subwoofer system amplifier module shall include the following controls: - POWER switch shall be an on/off switch for the loudspeaker system electronics; - ATTEN knob shall set the amount of attenuation applied to the input signal that is sent to the amplifier; - MODE switch shall select a low-frequency operation mode of either DEEP or Normal (DEEP processing not applied); - POLARITY switch shall select either Normal or Reverse polarity; - FRONT LED switch shall select whether the front LED tracks the rear-panel Power LED or the rear-panel Limit LED, or is off. The subwoofer system amplifier module shall include the following indicator LEDs: - POWER shall indicate that the power switch is in the ON position and the unit is not in Standby; - STBY (Standby) shall indicate that the loudspeaker system is in standby mode, which conserves energy when the unit is not in active use; - LIMIT shall indicate that limiting has taken place to avoid damage to the amplifier or loudspeaker; - SIGNAL shall indicate the presence of signal at the input connectors; - Front LED shall track the rear-panel Power LED, the rear-panel Limit LED, or be off, depending on the position of the Front LED switch. AC power requirements: The loudspeaker system shall have a universal power supply capable of operating with input AC power voltages ranging from 100 VAC to 240 VAC at 50 – 60 Hz. Power consumption at one-eighth power shall be 2.3 A at 100 VAC, 2.01 A at 120 VAC, and 1.13 A at 230 VAC. Cooling and protection: The loudspeaker system shall incorporate a 50 mm variable speed fan for on-demand cooling. The loudspeaker system shall incorporate amplifier protection circuitry including thermal limiting, output overcurrent protection, overtemperature muting protection, and GuardRail™. The loudspeaker system shall incorporate transducer protection circuitry including thermal limiting and excursion limiting, which prevents woofer over-excursion. Performance criteria: The subwoofer system shall meet the following performance criteria: - Frequency response shall be within -6 dB at 38 Hz to 124 Hz; - Useable frequency range shall be within -10 dB at 33 Hz to 143 Hz; - Maximum SPL at one meter shall be 135 dB peak. Dimensions and weight: The subwoofer system shall have the following physical characteristics: - Height shall be 21.6 inches (547 mm); - Width shall be 23.4 inches (594 mm); - Depth shall be 25.7 inches (653 mm), or 30.0 inches (762 mm) with optional casters attached to the rear; - Net weight shall be no more than 104 lb (47.2 kg). Model: The subwoofer system shall be the QSC Audio Products KLA181.