Architects and Engineers’ Specifications

The active two-way, full-range loudspeaker system shall incorporate one 15-inch low-frequency (LF) transducer and a 1-inch exit compression driver high-frequency (HF) transducer. The LF driver shall be mounted in a vented enclosure tuned for optimum low-frequency response. The HF transducer shall be loaded on a symmetrical constant directivity horn.

The system shall have a nominal coverage pattern of 75° (horizontal) x 65° (vertical). System frequency response shall vary no more than ± 3 dB from 57Hz to 18kHz measured on axis. The loudspeaker shall incorporate a Class G low-frequency amplifier capable of delivering 400 watts RMS over a frequency range of 20Hz–1300Hz. The system shall incorporate a Class AB 100 watt RMS amplifier specifically designed to power the HF driver over the range of 1300Hz – 20kHz. The amplifiers shall be mounted on an aluminum heatsink, which shall be mounted on the rear of the speaker system, and shall be convection cooled.

Thermal protection shall be provided by a thermal sensor mounted on the heatsink, which monitors the heatsink temperature and triggers the thermal protection circuit should the temperature exceed 140º F (60º C). The thermal LED shall light and the input signal shall be muted until the heatsink cools to a safe operating level, at which point the thermal protection circuit auto-resets and normal operation resumes.

Overload protection shall be provided by a limiter circuit, which monitors the low- frequency amplifier output and reduces the input level to the amplifier should the amplifier output begin to clip.

The loudspeaker enclosure shall have a trapezoidal shape and shall incorporate two side handles and a top and bottom relocation handle. The enclosure shall be constructed of a combination multi-ply wood and high- pressure injected structural resin, with a black PVC vinyl finish. The front of the loudspeaker shall be covered with a powder coated, weather-resistant perforated steel grille.

The active two-way full-range loudspeaker system shall be a Mackie SA1521.

Dimensions

SA1521

13.9 in/

 

 

35.3 cm

32.0 in/

81.3 cm

18.1 in/

 

 

 

19.1 in/

 

 

 

19.1 in/

46.0 cm

 

 

48.5 cm

 

 

 

48.5 cm

FREQUENCY RESPONSE GRAPH

10