JBL VTX Series User manual

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VTX Subwoofer Wiring Guide

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Introduction
JBL VTX Series subwoofers come equipped with Neutrik STX-Series speakON type connectors for connecvity to ampli-
ers. Depending on the applicaon and available cables, a number of wiring schemes can be used to achieve the de-
sired exibility while using the least amount of cables.
This document outlines wiring techniques used for powering JBL VTX Series subwoofer products with Crown I-Tech HD
series ampliers.
Internal VTX Subwoofer Wiring
All VTX series subwoofers (with the excepon of the VTX F18S) have the two woofer components independently wired
to the input panel NL connectors. One woofer is connected to Pin 1 (±) and the other to Pin 2 (±). The same pin cong-
uraon is used for NL4 and NL8 connectors, giving the user the choice to use either type of cable. For the case of NL8
connectors, Pins 3 and Pins 4 are wired as pass-through connecons (straight from one connector to the other) and
are not used to drive the subwoofer components.
Pin 1±
Pin 2±
Pin 1±
Pin 2±
NL4 Wiring for VTX Subwoofers NL8 Wiring for VTX Subwoofers
Pin 1± Pin 2±
Pin 3± = THRU | Pin 4± = THRU
VTX Subwoofer VTX Subwoofer input panel

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Crown Audio I-Tech 12000HD Wiring:
Crown Audio I-Tech 4x3500HD Wiring:
NL4 Wiring
Pin 1± Channel 1
Pin 2± Channel 2
NL4 Wiring
Pin 1± Channel 2
Pin 2± Not Connected
NL4 Wiring CH1/2
Pin 1 ± Channel 1
Pin 2 ± Channel 2
NL4 Wiring CH3/4
Pin 1 ± Channel 3
Pin 2 ± Channel 4
NL8 Wiring CH1-4
Pin 1 ± Channel 1
Pin 2 ± Channel 2
Pin 3 ± Channel 3
Pin 4 ± Channel 4
Crown Audio 2-channel I-Tech HD ampliers come with both channels 1 and 2 wired to the upper (CH1) NL4 connector.
This wiring method is typically used when powering 2-way bi-amplied loudspeakers and has Channel 1 outputs wired
to Pins 1 ±, and Channel 2 outputs wired to Pins 2 ±. The lower (CH2) NL4 connector is dedicated to Channel 2 and uses
Pins 1 ± (note: Pins 2 ± are not connected). The wiring conguraon for the output connectors is shown below:
The 4-channel Crown Audio I-Tech 4x3500HD includes 2 x NL4 connectors and has Channels 1 & 2 wired to the le NL4
and Channels 3 & 4 wired to the right NL4. An NL8 output connector is also available that contains all 4 amplier chan-
nels on Pins 1 ± through 4 ± respecvely. Output connector wiring conguraons are shown below:

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I-Tech 12000HD Standard Wiring (Discrete Mode):
Standard 4-conductor NL4 cables can be used to connect VTX subwoofers to Crown I-Tech HD ampliers. Using stand-
ard cables, each component within a VTX subwoofer enclosure is connected to an independent amplier channel as
shown in the drawing below. This wiring method is referred to as discrete wiring since each transducer within the en-
closure is discretely wired to an individual amplier channel.
Crown I-Tech 12000HD
NL4 Cable
Channel 1 Channel 2
Pins-1 ±Pins-2 ±
For this conguraon only the Channel 1 (Top) NL-4 connector should be used since it contains both Channel 1 and
Channel 2 of the iTech amplier. If the Channel 2 connector is used, one of the transducers will be le disconnected as
shown in the example below.
X
Not Connected
Crown I-Tech 12000HD
NL4 Cable
Channel 2
Pins-2 ±
Similarly, using the two NL amplier connectors for connecng mulple VTX subwoofer encloses should be avoided.
This wiring will only power 3 of the 4 subwoofer components, creang an 8-ohm load for Channel 1 and a 4-ohm load
for channel 2.
Incorrect
Channel 1 Channel 2
X
Not Connected
Channel 2
Pins-1 ±
8-ohm
Pins-2 ±
4-ohm
Pins-2 ±
4-ohm
NL4 Cable

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I-Tech 12000HD Standard Wiring Examples:
Standard NL4 jumper cables can be used to connect mulple subwoofer enclosures together in a daisy chain wiring
scheme. When connecng VTX subwoofers in this manner, each amplier channel powers half of the subwoofer group.
Below are some examples using VTX Subwoofers and discrete wiring:
Example: 6x VTX S25 powered by iTech 12000HD ampliers
Example: 12x VTX S28 powered by iTech 12000HD ampliers
CH1
CH2
CH1
CH2
CH1
CH2
Crown I-Tech 12000HD
CH1
CH2
CH1
CH2
CH1
CH2
CH1
CH2
CH1
CH2
CH1
CH2
CH1
CH2

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The discrete wiring mode reduces the number of cables required to wire a subwoofer system to a minimum, however
this is at the expense of exibility. Since mulple enclosures are powered and processed by the same pair of amplier
channels, DSP parameters such as presets or delay can only be applied to groups of subwoofers, not individual sub-
woofers. For opmum exibility, one subwoofer per amplier channel (parallel wiring mode) is recommended since it
is more convenient to implement cardioid subwoofer conguraons and Electronic Delay Steering (EDS). Parallel mode
operaon and adapter cable accessories are discussed in the following secons.
I-Tech 4x3500HD Standard Wiring (Discrete Mode):
The same wiring conguraon can be achieved with the Crown 4x3500HD amplier by using 2 x NL4 cables and 2 x NL4
jumpers as shown below:
NL4 Wiring CH1/2
Pin 1 ± Channel 1
Pin 2 ± Channel 2
NL4 Wiring CH3/4
Pin 1 ± Channel 3
Pin 2 ± Channel 4
CH1
CH2
CH3
CH4
Crown I-Tech 4x3500HD

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Parallel Wiring Mode:
Powering subwoofers in parallel mode with one subwoofer per amplier channel provides opmum exibility for im-
plemenng cardioid subwoofer conguraons and Electronic Delay Steering (EDS) as well as an opmum 4-ohm load
for power amplier channels. This wiring method allows for greater design and control exibility since each VTX enclo-
sure is connected to its own amplier and DSP channel. Parallel wiring also makes tesng easier since each subwoofer
can be tested independently.
In this conguraon a breakout cable or a rack I/O panel is necessary to wire the two subwoofer transducers to one
amplier channel. These adapter cables are easy to construct out of stock connectors and cables. The pin conguraon
is provided later in this document.
JBL Professional has partnered with cable manufacturer Link to oer these adapter cables as nished goods that can
be ordered internaonally directly from Link. Below are the part numbers for the products and to purchase, please
contact Link at: [e-mail]
LK VTX-NL-424
For use with 2 Channel Itech HD ampliers
NL4-1
NL4-2
LK VTX-NL-844
For use with 4 Channel Itech HD amplier
NL4-1
NL4-2
NL4-3
NL4-4
Female NL4 Female NL8

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I-Tech 12000HD Parallel Mode Example:
Using the LK VTX-NL-424 breakout cable, two subwoofer encloses can be connected to a single 2 channel iTech HD
amplier. The breakout cable allows each subwoofer to be connected to an independent amplier channel as illustrat-
ed in the example below. The breakout cable should always be connected to the CH1 (TOP) NL4 connector which con-
tains both Channel 1 and Channel 2.
NL4 Cable LK VTX-NL-424
I-Tech 4x3500HD Parallel Mode Example:
To implement parallel mode wiring on IT-4x3500HD ampliers, a pair of LK VTX-NL-424 adapters can be used in con-
juncon with 2 x NL4 cables that are directly connected to the amplier’s NL4 outputs. Alternavely, a single NL8 cable
can be used in conjuncon with the recommended 3rd party accessory shown below (Link USA LK VTX-NL-844) . In this
case the cable is connected to the NL-8 connector which contains all 4 channels. This makes for an easy and convenient
wiring scheme since a single NL8 cable can be used to independently power 4x VTX subwoofer enclosures and this sig-
nicantly reduces the number of cables needed.
NL8 Cable LK VTX-NL-844
CH1
CH2
CH1
CH2
CH3
CH4
Crown I-Tech 12000HD
Crown I-Tech 4x3500HD

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Breakout Cable Examples:
The example below shows an array of 6x VTX G28 wired using the LK VTX-NL-424 breakout cable. In this conguraon
each VTX subwoofer is driven by an independent amplier channel allowing for exible cardioid subwoofer circuing
and a unique delay value (EDS) for each enclosure.
When construcng large horizontal subwoofer arrays, the overall size of an array can have a negave impact on the
subwoofer coverage. The longer the array, the narrower the coverage. Electronic Delay Steering (EDS) is a technique
used to alter the coverage angle of a given subwoofer array by applying a specic pre-calculated delay value to each
subwoofer enclosure. The goal of EDS is to electronically alter the shape of a subwoofer array and widen the coverage
paern by creang a virtual arc. The radius of the arc controls the radiang paern of the array and each delay value is
carefully calculated to align all subwoofers to the virtual arc. Hybrid cardioid EDS subwoofer arrays provide even hori-
zontal coverage with 15—25 dB broadband SPL rejecon behind the array. Below is an example of a 12x G28 cardioid
subwoofer array and the appropriate delay values for a 90-degree coverage paern.
0.29ms 0.77ms 1.45ms 2.29ms 3.25ms0.00ms0.00ms0.29ms0.77ms1.45ms2.29ms3.25ms
NL4 Cable
LK VTX-NL-424

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Breakout Cable Examples:
The example below shows an array of 3x VTX S25 and a Vertec 4886 used as a front ll enclosure. The array is wired
using the LK VTX-NL-844 breakout cable to a single Crown iTech 4x3500HD amplier. In this conguraon the breakout
cable provides independent DSP for each speaker allowing for a cardioid conguraon for the subwoofers and a sepa-
rate preset for the VT4886 front ll. Mulples of this conguraon can be used for larger system conguraons.
Another interesng use case for the LK VTX-NL-844 breakout cable (unrelated to subwoofers) is when used with the
Vertec VT4886 line array system. The VT4886 is a 12-ohm passive line array element that can be driven and processed
by Crown iTech HD ampliers. Up to 4x VT4886 cabinets can be used on each amplier channel and up to 16x cabinets
per Crown iTech 4x3500HD amplier. An enre array of 16x elements can be powered using a single NL-8 cable and the
LK VTX-NL-844 breakout as illustrated in the example below.
NL8 Cable
LK VTX-NL-844
Crown I-Tech 4x3500HD
Crown I-Tech 4x3500HD

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Crown Audio VRack 12000HD:
Crown Audio VRack12000HD output panels have been specically wired to facilitate convenient operaon of VTX sub-
woofers in parallel mode (6 subwoofers per VRack, 1 subwoofer per amplier channel in parallel mode):
The NL4 connectors in the Blue group are all wired to individual amplier channels with Pins-1 and Pins-2 connected in
parallel at the VRack panel. This allows one VTX subwoofer to be connected per amplier channel while taking ad-
vantage of all parallel wiring benets without the need for addional breakout cables. The wiring example below
shows one VRack 12000HD powering a 6x G28 array.

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Crown Audio VRack 4x3500HD:
Unlike the VRack 12000HD, due to its high channel density, the Crown Audio VRack 4x3500HD does not contain a
speaker output panel and all connecons are made directly to the amplier's NL4 and NL8 connectors. As seen above,
to implement parallel mode wiring on IT-4x3500HD ampliers, a pair of LK VTX-NL-424 adapters can be used in con-
juncon with 2 x NL4 cables that are directly connected to the amplier’s NL4 outputs. Alternavely, a single NL8 cable
can be used in conjuncon with LK VTX-NL-844. Therefore, one VRack4x3500HD is able to power 12x VTX subwoofers
with either: 6x NL4 + 6x VTX-NL-424 adapters or 3x NL8 + 3x VTX-NL-844 adapters
RearFront
Example: 6x VTX V20, 3x VTX S25, 1x VT4886 powered by 1x V-Rack 4x3500HD

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Performance Manager:
Performance Manger can facilitate both Discrete and Parallel wiring modes for VTX Subwoofer products. The correct
wiring mode can be selected from the Array Conguraon menu and under the Sub Mode drop down menu. The Sub
Mode and amplier to speaker wiring connecon should be set correctly so that Performance Manager accurately rep-
resents the physical arrays and actual cabling.
Example: Discrete wiring selecon in Performance Manager
Example: Parallel wiring selecon in Performance Manager

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Based on the selected mode, Performance Manager adjusts the labels found on the speakers and amplier channels to
reect the type of wiring. For example, the subwoofer label S1 + S2 indicates parallel wiring mode and that both woof-
ers are driven by one amplier channel. When the label shows S1 | S2 that indicates discrete wiring mode and that
each woofer is powered by a dierent amplier channel.
Both the amplier channels and speakers have to display the same type of label for a valid connecon assignment be-
tween an amplier channel and a speaker. If the two are not the same, PM will prevent connecng an amplier chan-
nel to a speaker.
Parallel Mode Discrete Mode
Parallel Mode Discrete Mode

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Wiring:
NL8 NL4 - 1 NL4 - 2 NL4 - 3 NL4 - 4
Pin 1+ Pin 1+ | Pin 2+
Pin 1- Pin 1- | Pin 2-
Pin 2+ Pin 1+ | Pin 2+
Pin 2- Pin 1- | Pin 2-
Pin 3+ Pin 1+ | Pin 2+
Pin 3- Pin 1- | Pin 2-
Pin 4+ Pin 1+ | Pin 2+
Pin 4- Pin 1- | Pin 2-
Wiring:
NL4 NL4 - 1 NL4 - 2
Pin 1+ Pin 1+ | Pin 2+
Pin 1- Pin 1- | Pin 2-
Pin 2+ Pin 1+ | Pin 2+
Pin 2- Pin 1- | Pin 2-
NL4-1
NL4-2
Female NL4
NL4-1
NL4-2
NL4-3
NL4-4
Female NL8
Breakout Cable Pin Assignments:
LK VTX-NL-844
LK VTX-NL-424