An in-depth guide to the JBL VTX A8 compact line array system for touring and fixed installation
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An in-depth guide to the JBL VTX A8 compact line array system for touring and fixed installation

So, you’ve heard about the latest line array offerings from JBL and want to know a little more about what makes them so special - or perhaps this is your first introduction to the VTX A8 and B18 subwoofer - either way you’re in the right place! Below we will be exploring the more technical aspects of these loudspeakers and their accompanying accessories. 

In more than 75 years of JBL innovations, the VTX Series stands apart as a milestone in the practical application of creative engineering. VTX products herald the next generation in line array loudspeaker systems: a new era in performance, system integration and user friendliness. VTX contain multiple JBL patents in driver, waveguide and suspension technology, as well as custom amplification, DSP & control, and system management designs created in collaboration with fellow HARMAN Professional companies BSS and Crown.

VTX marries custom transducer design and in-house manufacture (JBL is one of very few loudspeaker makers to do this), breakthrough technologies and a comprehensive system approach which takes into account every user who will come into contact with it -  from the FOH mixing engineer to the systems engineer, rigger, road crew, warehouse manager, and of course, the audience.

Designed for portable and installed applications alike, the VTX Series features JBL’s trusted sound quality coupled with expert support and advanced tools that enable optimal specification, configuration and operation in any venue, anywhere in the world. The VTX Series delivers a comprehensive solution: the finest sound quality available, plus efficient and intuitive setup, tuning, networking, and control.

VTX A8 - Dual 8" Compact Line Array Loudspeaker With 110º Dispersion

After the A12, the VTX A8 is a next-generation line array element that delivers JBL Professional’s VTX A Series technology in a more compact solution for small to mid-size rental and installed applications. It was designed to solve the diverse sound reinforcement needs of production companies, rental houses, theatres and houses of worship, as well as front fills, side arrays or other auxiliary support for larger-scale VTX systems. Proprietary JBL woofers and our latest-generation high-frequency transducer and waveguide technology, provides unmatched performance, efficiency, and a consistent 110-degrees of horizontal coverage. 

The A8 combines two 8” woofers, four 3.5” midrange drivers and two 2” high-frequency drivers in a single low-profile cabinet. Proprietary double-flared low-frequency ports, precisely calculated for greater low-frequency performance extend the usable operating range down to 49Hz. The VTX A8 shares the VTX A Series’ patented rigging mechanism and suspension system for streamlined deployment, while a comprehensive suite of accessories open up a world of configuration options.


  • Innovative 3-way (bi-amp) design for best-in-class performance.
  • JBL Differential Drive™ woofers and Slip Stream™ ports deliver optimal bass response down to 49 Hz.
  • Common HF compression driver across A-Series products provides excellent sonic consistency.
  • Mid-frequency Radiation Boundary Integrator® (RBI) design maximizes transducer density and improves horizontal directivity.
  • Innovative auto-locking rigging mechanism for streamlined rapid deployment.
  • Built-in MF/HF passive network allows for reduced amplifier channels.
  • Full-face, enclosed grille for refined aesthetics and weatherization (IP55).
  • Comprehensive mounting accessories expand configuration options.
  • Integrates seamlessly with JBL system control and prediction software.
  • Compact, lightweight design.

VTX B18 - Single 18” Subwoofer

The VTX B18 is the smaller sibling to the B28 and is the next-generation single 18” subwoofer, designed to complement VTX full-range sound reinforcement systems. It features JBL’s new 2288H 18” woofer, engineered for improved linearity, increased sensitivity and extra-long excursion. The 2288H is based on JBL’s Differential Drive™, dual voice coil, dual-gap technology, which delivers better heat dissipation, lower power compression and wider dynamic range than conventional single-coil designs. The B18 incorporates JBL’s patented Slip Stream™ double-flared exponential low-frequency port design to improve airflow and reduce audible turbulence, even at maximum excursion.

The B18 shares the industrial design of the JBL’s VTX A-Series products and has the same width and suspension hardware as the VTX A8, allowing the two products to be used together in a variety of flown or ground-stacked configurations. The VTX B18 can be deployed in omni-directional or cardioid configurations, in arrays of up to 16 enclosures.


  • New JBL 2288 transducer offers increased sensitivity, lower distortion and improved linearity.
  • JBL SlipStream™ double-flared exponential ports for reduced noise and air turbulence.
  • Built-in, easy to use, spring-loaded rigging system.
  • Support for omnidirectional and cardioid array configurations.
  • Front and rear NL4 connectors streamline cable management.
  • Channel-selection switch minimizes wiring requirements.
  • Mechanically compatible with the VTX A8 and all A8 suspension accessories.
  • Full integration with JBL system prediction and control software.
  • Comprehensive mounting accessories expand configuration options.
  • Compact design.


Transport Dimensions

As is probably clear by now, the A-series sets itself apart from other line array systems on the market by the sheer amount of innovation that goes into every design phase of these speakers. Below we’ll delve a bit deeper into the technologies that are the most important and explain in more detail some of the terms used above such as SlipStream™ double-flared exponential ports, Differential Drive™ or Radiation Boundary Integrator®.

One of the main things that JBL wanted to get right was how easy the A-Series would be in use, from transport to rigging. For this reason, they gave careful consideration to the dimensions of the boxes on the transporters and how they would fit nicely onto trucks, both American and European. This means you can keep transport costs down to a minimum.

Rigging System

The brand-new patented rigging system couldn’t be easier to use and is made even easier with Line Array Calculator 3 (LAC III), a free piece of acoustic prediction software that helps you to find the best coverage for your event and tells you what angles to set the boxes at as well as pick points for the frame. You can access or share the information via a QR code and set the angles while the boxes are still in their transporters. You then just raise the boxes and they set to the correct angles. This works the same in reverse when breaking down the system, you release the pins and drop four boxes at a time on to the Vertical Transporters and they are ready to go.

The A-Series also allows for flexible deployment be that either flown or ground stacked through the large variety of accessories such as the Array Frame, Suspension Bar or Base Plate (all listed below). When it comes to deploying your subs it couldn’t be easier too with front and rear NL4 connectors allowing easy implementation of omni or cardioid sub arrays.

B18 Sonic Innovations

The main innovation in the B18 single 18” sub is the 2288H neodymium Differential Drive™ transducer. It has +4dB sensitivity compared to most other comparable drivers on the market meaning it goes twice as loud and it manages to do it with less distortion resulting in a more musical system. At the heart of the 2288H driver is Differential Drive™ technology which in essence replaces the traditional single coil with a double coil system as illustrated below.

This allows for better cooling due to the dual gap and integrated aluminium heat sink, a larger maximum excursion through the mechanical linearity of the suspension and the dual coil design, more uniform impedance and extended output of higher frequencies. The compact nature of the Differential Drive™ motor means that JBL can create a driver one third the weight of a traditional one. 

All this equates to a lighter, louder, more efficient and more musical low frequency driver.

Another reason the B18 manages to kick as hard as it does is the Slipstream™ port design. At high sound pressure levels, air flow turbulence inside a vented enclosure’s port can create noise that sounds like woofer break up. The patented Slipstream port uses a double-flared design (internal as well as external flares) to ensure low frequency efficiency while eliminating noise caused by port turbulence and unwanted vortices. The double-flared shape of the port is precisely calculated for greater low-frequency extension more accurate bass response at all playback levels.

A8 Sonic Innovations

Next we’ll have a look at how JBL managed to create such an accurate tight HF section with the A8 and A12.

Harman took all their research into ring radiator HF transducers over the past decade including the D2 dual diaphragm dual voice-coil compression driver from the legendary M2 studio reference monitor, and took several innovative steps to advance it to the next level. 

The D2 driver was revolutionary when it was developed and JBL have since then managed to further perfect the driver to get even more out of it. The fact that it has the improved HF section from a studio monitor can definitely be heard when listening to the A-Series as it is often hard to believe that the crystal clear sound you’re hearing is actually being produced by line array elements. 

As can be seen from the D2 driver above it had a dual diaphragm to create enough power. In the VTX-series they incorporated the phase plug into the waveguide and bolted it directly onto the front baffle of the speaker thus hugely increasing the efficiency of the HF driver reducing the amount of power needed to force the sound out which allowed them to use a singular annular diaphragm instead of the two previously needed.

The requirement of the new VTX A-series HF driver - the JBL 2423K - was to have high efficiency but also smooth response with low distortion.

This is partly achieved by using an annular diaphragm which isn’t subject to the break up modes of a conventional dome diaphragm. This means you get a distortion free HF signal which extends way beyond conventional compression drivers.

However, what makes the 2423K sonically superior to the D2 is that by combining the waveguide and phase blade JBL removed the resonances associated with forcing the sound waves through a waveguide.  Additionally JBL engineered a unique ‘flower shaped’ exit path for both the exit slot and base of the phase blade to optimise the linearity of the output.

The phase plug is elongated so it forms a thin blade running the entire length of the centre of the exit slot, rather than extending to a point like a traditional compression driver. This design allows for better coupling, the true benefit of which is discussed in more detail below.

JBL’s proprietary Radiation Boundary Integrator™ (RBI) was first designed for the VERTEC® Series of line array loudspeakers. This unique JBL innovation resulted in broader & more stable horizontal coverage by combining the mid and low frequencies so the transition across each band is uninterrupted, undistorted and seamless.

JBL has designed the RBI so that it bolts directly to HF exit path for seamless combining. A patented, tuned resonant-chamber is integrated into the waveguide itself, effectively eliminating throat-related cancellations due to back pressure from the mid-range section. The result is extremely even pattern control and coverage, where all listeners hear a consistent flat, frequency response and also allows for maximum transducer density meaning smaller lighter speakers.

If you take another look at the picture above you can see the HF waveguide is flush with the edge of the box. This, matched with a unique system of suspension hardware, provides a continuous baffle surface between the boxes indicated by the orange line in the image below. The 2423K HF driver has also been designed so JBL can stack multiple drivers directly on top of one another to create a near seamless line source which bolts directly to the baffle and RBI waveguide.

This means that even at the largest cabinet angle of 10 degrees, there isn’t a gap between the front of the waveguides, which allows the array to work as a true line source.

With other line array elements set to the widest angles there is a break between the boxes meaning an interruption in the line source. This is often remedied with software such as EDS (electronic delay steering) which corrects the line source but introduces phasing issues. By designing the speakers to work mechanically without the need for additional software results in a truer image. Where other manufacturers need to use a load of additional processing and then suffer the phasing and power compromises which that incurs, HARMAN is engineering out the acoustic compromise at the source. It’s like to adage, ‘it’s far better to get it right at source than try to ‘fix it in the mix’.

Full System Integration

Finally, what makes the VTX Series a great choice is that you are not just using a product, you are gaining access to an expert system. Tools for system design and all the components to analyse, configure, set up and control a VTX system are all part of the JBL commitment to total system integration and support. The goal is maximum efficiency and the highest possible level of performance in any venue, anywhere in the world. 

The A8’s can of course be used by its own or it can be part of a larger system in conjunction with the VTX B18, A12 or A12W and the B28. The VTX A8 expands the JBL VTX A Series to offer audio professionals a complete toolset for designing optimal sound systems for any application. Whole system integration with the latest tuning can now easily be done from Performance Manager with the JBL Application Engineered Compact Series having been added for front and balcony fill applications.

We hope this guide to the JBL VTX A8 & B18 has been useful and has given you some insight into what this powerful series can offer for your professional needs.