CONTROL 321C/CT, 322C/CT & 312CS SYSTEM ASSEMBLY
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).
IMPORTANT: SECURING SPEAKER ASSEMBLY TO THE BUILDING STRUCTURE
9
JBL Professional Control 300 Series
Using a different brand compatible back box
-- Screwholes in the metal baffle are provided
corresponding with two common mounting systems.
Utilize the system that works with that particular
back box.
Ceiling Preparation -
Cut a 14.9 x 14.9 inch
(378 x 378 mm) hole in the ceiling to allow
sufficient room for the loudspeaker baffle.
Using JBL Professional’s MTC-300BB12
Back Box
-- The MTC-300BB12 is
compatible with two common mounting
systems for installing the loudspeaker
/ baffle to the back box;
either
of these
mounting systems may be utilized. Screws
are included with the MTC-300BB12 Back
Box.
Using 4 pcs - M4 x 38mm powder coated
machine screws, attach the metal grille
to the baffle. Be sure to match the grille
mouting holes to the weld nuts on the baffle
assembly.
4 pcs - M4 x 14mm sheet metal
screw for attaching the driver /
baffle to the back box. Match to
corners on back box.
1 Point Each Corner
6 pcs - #10 x .75 in (19mm) sheet
metal screw for attaching the
driver / baffle to the back box.
Match to clip nuts on back box.
1 Point Each End
2 Points Each Side
4 pcs - M4 x 38mm powder
coated machine screws for
attaching the metal grille to
the baffle. (Included with JBL
Profesional grilles.)
IMPORTANT!
When installing the
MTC-300BB12 with
a Control 321C/CT,
322C/CT & 312CS
models see “Securing
Speaker Assembly to
the Building Structure”
details below.