APS-SUB
The system should be a low bass extension, driven and protected by a special controller output stage. The bass extension should contain an 18 inch long excursion loudspeaker in a bass reflex tuned cabinet. The used loudspeakers should be impregnated weatherproof. The continuous load capacity of the system should be 1,300 watts. The loudspeaker should have a nominal impedance of 8 Ohm. The usable system bandwidth should be extended down to 28 Hertz (-6 dB) by using the low bass extension. The system shall have an omnidirectional and - in conjunction with other bass expansions of the same type and with special system presets provided by the manufacturer - kidney-shaped radiation characteristic. In combination with other loudspeakers of the same type and in combination with full-range loudspeakers, the bass extension should function as part of an array without affecting the wave front. The low bass loudspeaker should have an M20 thread on its upper side for a 36mm high stand flange to accommodate a full-range loudspeaker. The maximum peak sound pressure level should be 138 dB, measured with pink noise at a distance of 1m, under half-space conditions and with a crest factor of 6. The loudspeaker cabinet should be made of birch multiplex and sealed with a weather and moisture resistant polyurea coating (PU). The front of the loudspeaker should be provided with a ball-proof protective grille, which is backed with acoustically neutral foam. Its physical dimensions should be 674 mm in width, 570 mm in height and 596 mm in depth. The weight of the loudspeaker shall be 45 kg. The loudspeaker box shall have an integrated 2-point suspension with which other loudspeakers and special accessories can be mounted. The speaker should be able to be mounted to a stacked or suspended line source using accessories with speakers of a different type. The speaker should be connected via two 4-pole SpeakON sockets on the rear panel. The manufacturer's warranty shall be 5 years.