Architectural Specifications:
The subwoofer loudspeaker shall consist of a 200 mm (8.0 in) low frequency transducer in a vented enclosure. The voice coil shall be 38 mm (1
½
in) in diameter and the
coil former shall be of aluminum for maximum heat dissipation.
Performance specifications of a typical production unit shall be as follows: Measured sensitivity (SPL at 1m [3.3 ft] with 2.83V input, averaged from 60 Hz to 100 Hz) shall
be at least 95 dB-SPL (
/2 loading). Usable frequency response shall extend from 42 Hz to 200 Hz (10 dB below rated sensitivity) with no external equalization. Rated power
shall be at least 100 watts continuous pink noise power, defined as conforming to international standard IEC268-5 (shaped pink noise with peak-to-average ratio of 6 dB) for
a period of 100 continuous hours.
The system shall be protected against damage from occasional overpowering via full range series lamps that limit the power to the transducer (Control 18S, not Control
18ST).
The enclosure shall be constructed of high-impact polystyrene for protection against the elements in outdoor applications, and for paintability. The grille shall be
completely zine-coated for resistance against rusting, shall be bake-painted and shall be secured via screws to keep it in place when facing downward.
The transducer shall have a polypropelene cone and a butyl rubber surround. The system shall withstand Mil Spec 810 testing with specified time durations for exposure to
the following environments with no effect on its acoustical performance or structural integrity: salt spray (method 509.3), temperature -19°C to 49°C (method 501.3 and 502.3),
95% humidity (method 507.3) and ultraviolet (method 505.3). The system shall have an IEC 529 splashproof rating of IP-X4.
For theft deterrence, the installation access area shall be hidden behind a snap-out cover, and the access area shall be on the front of the loudspeaker for ease of
installation and adjustment. The loudspeaker shall be rotatable over a minimum of ±35° in all directions via a ball-type mounting system. The ball mechanism shall be internal
to the cabinet to allow low-profile mounting and better stability via a short moment arm. The logo shall be rotatable for proper orientation when the loudspeaker is mounted
horizontally or vertically.
The external wiring connectors shall be spring loaded and gold plated, and shall accept bare wire. Overall cabinet dimensions shall be no greater than 380 mm (15.0 in)
high by 280 mm (11.0 in) wide by 218 mm (8.6 in) deep.
Control 18S: The loudspeaker shall weight no more than 6.3 kg (14 lb) and nominal impedance shall be 8 ohms.
Control 18ST: The loudspeaker shall weight no more than 7.3 kg (16 lb) and shall be equipped with a special subwoofer-capable transformer for use in either 70.7 or 100V
distributed-line speaker systems, with taps selectable by rotary switch located on the front panel so that the speaker does not have to be removed to adjust tap settings. Taps
shall be nominally 60W @ 70V, 30W@ 70V (60W @ 100V), 15W @70V (30W @ 100V), and 7.5W @ 70V (15W @ 100V).
The loudspeaker shall be the JBL Model Control 18S (Control 18ST).
