d&b J-INFRA - Manual (Page 4)

J-INFRA
J-INFRA loudspeaker
The J-INFRA is the cardioid infra subwoofer for the J-Series. It can be
used to supplement J-Series systems consisting of J8, J12 and J-SUB
cabinets in various combinations. It extends the frequency response of a
J-Series system down to 27 Hz
J-INFRA cabinets can be used ground stacked in a conventional L/R
setup as well as arranged in a subwoofer array. One J-INFRA cabinet
provides additional very low frequency energy for two J-SUB
subwoofers.
A detailed description of planning and designing J arrays is given in the
technical information “TI 385 d&b Line array design, ArrayCalc” which is
provided with the J Flying frame and the d&b ArrayCalc Simulation
software.
The J-INFRA cabinet is an actively driven 2-way bass-reflex design
housing three long excursion neodymium 21“ drivers, two drivers face
to the front while one driver radiates to the rear of the cabinet.
Front and rear drivers are driven by separate amplifier channels and
operate in independent bass reflex chambers. Through its cardioid
dispersion pattern this setup avoids unwanted energy behind the system
and greatly reduces the reverberant field at low frequencies providing
highest accuracy in low frequency reproduction. J-INFRA cabinets have
to be arrayed with a minimum distance of 60 cm (2 ft) between
adjacent cabinets.
The J-INFRA cabinet is constructed from marine plywood and has an
impact and weather protected PCP (Polyurea Cabinet Protection) finish.
The front and rear of the loudspeaker cabinet are protected by a rigid
metal grill. The side panels incorporate eight handles. Two runners
extend from the rear to the front panel of the cabinet protecting the
bottom panel against scratching. Two correspondingly shaped recesses
are incorporated in the top panel of each cabinet to accept these
runners and prevent cabinet movement when stacking J-INFRAs. The
cabinet front is fitted with four catches for securing an optional
transport lid E7920.
Connections
1
2
3
4
5
Sense Drive
Connector wiring
The J-INFRA cabinet is fitted with a single NLT4F connector. It uses the
pin assignments 1+/1– for the front drivers. Pins 2+/2– drive the rear
driver.
The J-INFRA can be supplied with an EP5 or NL8 connector as an
option. Pin equivalents of NLT4F, EP5 and NL8 connectors are listed in
the table below.
LF +
Front
LF –
Front
LF +
Rear
LF –
Rear
SenseDrive
Front
NLT4F 1+ 1– 2+ 2– n.a.
EP5 1 2 3 4 5
NL8 1+ 1– 4+ 4– 3–
J-INFRA Manual (1.1 EN) Page 4 of 8