precise balancing and tuning of the speaker. The enclosures shall be
constructed throughout of 19.1 mm 3/4 inch high density board, with screwed
and glued joints, durably braced, and padded with fiberglass where
acoustically required.
Speaker enclosures shall have a [25] [45] degree
[_____] vertical dispersion and [90] [120] degrees [_____] horizontal
dispersion. The effective length of throw shall be a minimum of [15] [40]
[60] [_____]m [50] [130] [200] [_____] feet.
2.7.5
Wall Baffle Speaker Enclosures
The wall baffle speaker shall be of particle board construction covered
with [walnut laminate] [_____] and complete with [black] [_____] cloth
grille. Baffle shall feature 9.5 degree slope to provide directional sound
dispersion offset in the direction of radiation. Wall baffle enclosure
shall come equipped with a wall mounting bracket designed to assure a rigid
mounting to any flat surfaces.
2.7.6
Ceiling Speaker Enclosures
Ceiling speaker enclosure shall be constructed of heavy gauge cold steel
with interior undercoating and 38 mm 1 1/2 inch thick high density
fiberglass 24 kg per cubic meter 1-1/2 lbs per cu. ft. The unit shall be
[round] [square] and designed for [recessed] [surface] installations which
will be accomplished via [standard screw] [torsion spring] [flange mount]
mounting. Recessed models shall have a rust-preventive, [textured black
coating] [_____] and the surface mount unit finished in textured [white]
[_____]. Enclosure shall include four triple compound conduit knockouts.
2.8
SPEAKER SWITCHING PANEL
**************************************************************************
NOTE: Delete if paging function is not required.
Show zone boundaries on the drawings.
**************************************************************************
2.8.1
Selector Switches
Zone control shall be provided for the paging function. The speaker
switching panel shall contain at least [_____] double-pole, [[4-] [3-]
position] [push button] selector switches and shall be [rack-mounted] [desk
mounted] [selector switches built in microphone]to activate priority
relays. Selector switches labeling shall be provided to identify the zones.
2.8.2
System Power supply
Power supply shall be provided for priority relays and controls,
rack-mounted and sized for a capacity equal to 200 percent of the as-built
control system, and shall operate at 24 Vdc. Input and output shall be
protected to permit Class 2 wiring in accordance with NFPA 70.
2.9
AM/FM EQUIPMENT
2.9.1
AM/FM Tuner
AM/FM tuner shall be rack-mounted and shall as a minimum conform to the
following characteristics:
Tuning Range:
AM - 540 to 1605 kHz
SECTION 16770
Page 12
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