The J-INFRA is a cardioid infra subwoofer that can be used to supplement J-Series systems consisting of J8, J12 and J-SUB cabinets. It extends the frequency response of a J-Series system down to 27 Hz and can only be used in ground stacked configurations in conventional left/right set-ups, as well as arranged in an infra subwoofer array. It has two bass-reflex chambers containing three 21" drivers, two facing forward in one chamber that are driven from one channel of the d&b amplifier and one facing backwards driven by another amplifier channel. Through this driver set-up its cardioid dispersion pattern avoids unwanted energy behind the system and greatly reduces the reverberant field at low frequencies, providing highest accuracy in low frequency reproduction. Selecting Hypercardioid mode in the amplifier optimises the tuning of front and rear channels for a maximum rejection at the left and right sides behind the cabinet. 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 and the side panels incorporate eight handles. The cabinet front is fitted with four catches for securing an optional wooden lid.
The d&b audiotechnik loudspeaker range is designed exclusively for operation with d&b amplifiers. These provide power as well as comprehensive control and protection functions tailored to achieve the performance, reliability and longevity associated with the d&b System approach. The d&b D80 amplifier is recommended to drive the J-INFRA. The d&b 30D amplifier can also be used with the appropriate loudspeaker configuration selected.
The 2-Way active mode for the J-INFRA requires two channels of the D80.
|Frequency response (–5 dB standard)||27 Hz - 60 Hz|
|Frequency response (–5 dB 70 Hz mode)||27 Hz - 70 Hz|
Max. sound pressure (1m, free field)1
|Cabinets per D80/30D||2|
|Configuration||Large format cardioid subwoofer|
|Nominal impedance||3 Ω (front) / 6 Ω (rear)|
|Power handling capacity (RMS/peak 10 ms) front||1200/4800 W|
|Power handling capacity (RMS/peak 10 ms) rear||600/2400 W|
|Components||3 x 21" driver|
1 x NLT4 F
optional 1 x EP5 or 1 x NL8
|Dimensions (H x W x D)||
685 x 1180 x 10403 / 1158 mm
27.0 x 46.5 x 41.03 / 45.6"
Application information is presented for guidance only. d&b reserves the right to make any necessary changes to the products and the published specifications. As part of the ongoing development program d&b tries to maintain the highest degree of product compatibility.
|EU Declaration of Conformity (CE)||International||04.10.2016||51 KB|
|J-INFRA Manual 2.2||English||29.07.2017||717 KB|
|J-Series cables and adapters||International||30.01.2014||830 KB|
|The J-Series brochure||English||19.05.2017||6 MB|
|TI 385 d&b Line array design, ArrayCalc V9.x||English||17.01.2018||1 MB|
The subwoofer system shall have forward and rear facing elements to produce cardioid or hypercardioid dispersion patterns. The front and rear elements of the subwoofer shall be driven by separate channels of a dedicated and compatible amplifier, containing loudspeaker specific configurations and algorithms to select cardioid or hypercardioid operating modes. The subwoofer shall exhibit extremely low power compression this reason use very large vents.
The cabinet shall incorporate 3 x 21" neodymium LF drivers, two forward and one rear facing.
The enclosure shall be constructed from marine plywood with an impact resistant and weather protecting PCP (Polyurea Cabinet Protection) finish. The cabinet front shall be protected by a perforated steel grill backed with acoustic foam.
The power handling of the forward elements shall be 1200/4800 W (RMS/peak 10 ms) while the power handling of rear facing element shall be 600/2400 W (RMS/peak 10 ms).
The frequency response (–5 dB) measured on axis shall extend from 27 Hz - 60 Hz in standard mode and form 27 Hz - 70 Hz in 70 Hz mode with a maximum sound pressure level (SPLmax) (peak/1 m) of at least 144 dB.
The cardiod dispersion shall be switchable between cardioid and hyper cardiod.
The connection panel on the back shall be recessed and fitted with speakon NLT4 F/M sockets (EP5 or NL8 connectors as an option).
The dimensions (W x H x D) shall not exceed 1180 685 x 1158 mm (46.5" x 27" x 45.6") and shall weigh no more than 152 kg (335 lb).
The loudspeaker shall be the J-INFRA by d&b audiotechnik GmbH.