JBL MTC-300BB12 Datasheet
3 Cubic Foot Backbox
for Control 300 Series
MTC-300BB12
Professional Series
Key Features:
䉴
Extra-thick 16 gauge metal construction.
䉴
Lined with 12 mm (½ inch) thick
MDF to eliminate resonances and
to provide extra bass response.
䉴
Knockouts on top and all four
sides.
䉴
Dual mounting system for baffle.
䉴
Mounting platform for an optional
high-power 70V/100V transformer.
Dimensions:
12" Drivers
Specifications:
External Volume: 3 cu ft, nominal
Internal Volume: 2.4 cu ft.
Knockouts: 22.1 mm (0.87 in) diameter opening
Dimensions (Height): 308 mm (12.1 in) above ceiling
(Width): 587 mm (23.1 in)
(Depth): 461 mm (18.2 in) cabinet
(Ceiling Cut Out): 378 x 378 mm (14.9 x 14.9 in)
Safety Agency Rating: Suitable for use in air handling spaces, per
Net Weight: 20.6 kg (45.5 lbs)
Shipping Weight: 23.1 kg (51 lbs)
Included Accessories: 4 pcs M4 x 14 mm machine screws for one system
JBL continually engages in research related to product improvement. Changes introduced into existing products without
notice are an expression of that philosophy.
Five (5) locations: 1 on top panel
1 on each side and end
panel
324 mm (12.6 in) total height
505 mm (19.9 in) including side tabs
U.L.-2043,U.L.-1480, NFPA90 & NFPA70A
of mounting baffle to backbox.
6 pcs #10 x 0.75 inch metal screws for another
system of mounting baffle to backbox.
4 pcs M4 nuts for optional transformer mounting
18.2
(461)
14.7
(373)
13.9
(353)
23.1
(587)
12.5
(318)
14.7
(373)
13.9
(353)
12.5
(318)
10.3
(262)
12.6
(324)
12.1
(308)
23.1
(587)
14.7
(373)
Slot
1.1 x 0.24
(28 x 6)
1.9
(48)
14.7
(373)
18.2
(461)
19.1
(486)
19.9
(505)
Dimensions in inches (mm)
Dimensions in inches (mm)
)
䉴 Control 300 / MTC-300BB12 Backbox Assembly
MTC-300BB12 is compatible with two common mounting systems for installing the loudspeaker/baffle to the backbox. Either of these mounting systems may be utilized. Begin by cutting a 14.9 x 14.9 inch (378 x 378 mm) hole
in the ceiling to allow sufficient room for the loudspeaker baffle.
Baffle Mounting
Option #1
6 pcs #10 x 0.75 inch
Sheet Metal Screws
Use with Backbox’s 6 Speed Nuts (also called
Clip Nuts or Tinnerman Nuts), shown at right.
2 Points Each Side
1 Point at Each End
IMPORTANT!
See “Securing Loudspeaker
Assembly to the Building
Structure.”
6 pcs - #10 x .75 in (19 mm) sheet metal screw
for attaching the driver / baffle to the back box.
Match to clip nuts on back box.
4 pcs - M4 x 38 mm powder coated
machine screws for attaching the metal
grille to the baffle. (Included with JBL
Professional grilles.)
Baffle Mounting
Option #2
4 pcs 4 mm x 14 mm
Threaded Machine Bolts
Use with Backbox’s four Threaded
Insert Points, shown at right.
IMPORTANT: SECURING THE LOUDSPEAKER ASSEMBLY TO THE BUILDING STRUCTURE
The backcan MUST be secured to the building structure by qualified personnel in accordance with safe installation
practices. Use suspension materials, connection fixturing, and methods that are appropriate for the building structure and installation conditions. Employ a minimum 5:1 safety factor for each suspension point, or higher if required
by code. For MTC-300BB12 with a Control 321C/CT, 322C/CT or 312CS, a 5:1 safety factor requires that each suspension point be rated to support a minimum of 156 kg (345 lbs).
1 Point Each Corner
4 pcs - M4 x 14 mm sheet metal
screw for attaching the driver / baffle
to the back box. Match to corners
on back box.
Mounting Location for Optional Transformer
A mounting platform for an optional high-power 70V/100V transformer is provided inside the backbox, on one of the side walls.
The four mounting studs are “M4 x 12 mm” and are spaced at 2.8 x 2.7 in (70 x 67 mm).
JBL Professional
8500 Balboa Boulevard, P.O. Box 2200
Northridge, California 91329 U.S.A.
A Harman International Company
©Copyright 2007 JBL Professional
SS MTC300BB12
CRP 5M
07/07
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