d&b J12 - Manual (Page 4)

J12
Fig. 1: J12 loudspeaker
The J12 is a line array loudspeaker for large-scale sound
reinforcement. When the J Flying Frame is used, J12 cabinets can be
flown in vertical columns with up to 24 cabinets producing a 120°
constant directivity dispersion pattern in the horizontal plane.
The J12 is acoustically and mechanically compatible to the J8 line array
module which provides a 80° horizontal dispersion. J-Series arrays may
consist of a combination of J8, J12 loudspeakers and J-SUB cardioid
subwoofers.
The J12 cabinet is a 3-way design housing 2 x 12" neodymium LF
drivers, one horn-loaded 10" MF driver and two 1.4" exit HF
compression drivers with 3" coils mounted to a dedicated wave shaping
device. The cylindrical wave segments of each cabinet couple without
gaps and sum up coherently. Splay angles between adjacent cabinets
can be set in the range from 0° to 7°.
J12 cabinets are driven by the two channels of the d&b D12 amplifier
providing the active crossover between the LF and mid/high sections.
MF and HF drivers are crossed over passively within the cabinet.
All components are arranged symmetrically around the center axis of
the cabinet to produce a perfect symmetrical dispersion pattern. This
setup allows a very smooth crossover design with a well defined
overlap of adjacent frequency bands resulting in a very consistent and
accurate horizontal dispersion. Due to the dipolar arrangement of the
low drivers the nominal dispersion of 120° is maintained down to
200 Hz.
The J12 frequency response extends from 48 Hz to above 17 kHz.
The J12 cabinet is constructed from marine plywood and has an impact
and weather protected PCP (Polyurea Cabinet Protection) finish. The
front of the loudspeaker cabinet is protected by a rigid metal grill. The
side and rear panels incorporate four handles.
J-Series rigging components
J-Series arrays
Cabinets are mechanically connected using the rigging strands at both
sides of the cabinet front and a central strand at the rear of the cabinet
which also serves as a heat sink for the MF driver. All necessary rigging
components are mounted to the cabinet and folded or slid out when
needed.
A detailed description of the J-Series rigging components is given in the
J-Series Rigging manual which is provided with the J Flying frame.
A detailed description of planning and designing J arrays is given in the
technical information "TI 385 J, Q and T-Series system design,
d&b ArrayCalc" which is also provided with the J Flying frame.
The d&b ArrayCalc array calculator can be downloaded from the d&b
website at
www.dbaudio.com .
J12 Manual (1.2 EN) Page 4 of 8