JBL in Theatre Applications
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JBL in Theatre Applications

Source material in theatre can be incredibly dynamic compared to other audio productions. This creates some specific demands on the audio system. It needs to be capable of natural sounding 'unamplified' audio to extremely high impact; it needs to reproduce spoken and sung word, live instruments and recorded content. If an audio system is to excel at this, it needs to be meticulously designed and engineered.

At Sound Technology we are privileged to have access to the extensive JBL Professional catalogue, and as such are able to provide solutions for the full breadth of theatre applications.  With our scalable and versatile portfolio we can offer anything from small prop speakers through to a full Front of House line array system.

JBL is one of very few loudspeaker manufacturers which designs and builds their own drivers, as opposed to buying off-the-shelf components and creating a speaker around them. The patented driver technologies at JBL are class-leading and provide an extremely accurate reproduction of spoken word that lends itself very well to theatre applications. 

In this blog we'll look at JBL Professional's solutions for theatre sound, from small prop speakers through to a full Front of House line array system.

Lets take it from the top

We'll start at front of house with the with the VTX A8 compact Line Array.

The A8 is a new generation of line array that delivers JBL’s flagship VTX A-Series technology in a compact form factor. It's loaded with two 8” woofers, four 3.5” midrange drivers and two 2” high frequency drivers, all proprietary JBL transducers, developed and manufactured in-house. 

The passively-crossed mid and high frequency sections reduce amplifier channel count allowing you to power up to 8 boxes with a single Crown iTech 4x3500. JBL’s waveguide technology delivers fantastic unmatched performance and efficiency with accurate 110 degree horizontal coverage.

High Frequency 

A8's killer weapon is the high frequency driver design, so let's get technical for a minute.  The 2423K is a Neodynium compression driver designed with the aim of having both high efficiency and also smooth response and no 'ringing' with pistonic motion to 15kHz. JBL achieved this by using an annular diaphragm which isn’t subject to the break-up modes of a dome diaphragm. This means you get a distortion free HF signal which extends way beyond conventional compression drivers. 

In real terms that means super clean, super clear content with none of the distortion that is inherent in most other loudspeakers and that we've become accustomed to hearing. 

When we demonstrate A8 in our Letchworth demo facility, it is often how commented clean and natural it sounds. Vocals, speech and reverb tails have amazing clarity, and tiny details really shine through, as if they're being heard on a pair of studio monitors.

For an in-depth look at the VTX A8 read our tech guide

VTX A8 chosen for new Bob Marley Musical

Tony Gayle chooses VTX A8 as his preferred PA system for the new production of Get Up, Stand Up!

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LF Section

While a lot of the credit for A8's reputation is rightly given to the high frequency section, the low end is equally deserving.

Many comments have been made over the amount of punch from such a compact speaker. Even though the A8 is only a dual 8’, when you run the system at full range it is capable of still going down to 49Hz, This is again credit to the transducer and box design from the engineers at JBL.  

The LF drivers use JBL’s patented Differential Drive. Differential Drive features a dual voice coil, a pair of in-line voice coils in separate magnetic gaps. This gives a more effective use of available space and allows more efficient removal of heat from the motor structure. The voice coils are wound in reverse and are in opposite polarity to one another, reducing magnetic flux leakage and focusing more magnetic energy in the gaps where it is needed and providing control of the driver throughout its entire excursion path. 

JBL also employs newly-developed venting paths and cooling fins within the magnet assembly to further reduce heat build-up in the coil gap. All these technologies provide us with higher power handling, lower distortion and greater linearity with reduced power compression when driving hard for long periods. These are also some of the key characteristics of VTX subwoofers. Many users notice that as the large woofers in these units reach maximum output/excursion, they still sound as if they’re operating comfortably – in a more linear fashion – than traditionally designed woofers.

Having this level of engineering in the box it allows us to run the speakers full range with very impressive results and in some applications run without the need of additional subwoofers.

Rigging and Management

Touring theatre is not a natural environment for line arrays. Theatre auditorium layout can complex and load in is rarely as easy as is for a concert production, so ease and speed of set up is vital.

The A8 shares its VTX A series patented rigging mechanism and suspension system for extremely quick deployment, which for touring theatre shows makes setup at a new venue much less of a headache!  See our in-depth A8 article for more on the rigging system.

JBL understands that the user also needs flexibility and ease of use with system programming and design, and it produces a suite of tools to assist with this. Performance Manager to control and monitor your system easily and confidence; Line Array Calculator III and Arraylink for quick and easy design & deployment.

Congress Theatre

VTX A8 fulfils the Eastbourne theatre's requirements for a system capable of hosting a wide range of productions.

Read Full Case Study

Complementing the Main System - Fills and Balconies

No theatre sound system is complete without point source speakers as fills and delays to cover the hard to reach areas of the house.

JBL's AE Compact range is a fantastic solution for this application, with their high output characteristics, and tuning which complements A8 in both sound and aesthetics.

The AE Compact family consists of eight high-output, two-way loudspeaker models incorporating either single or dual woofers, including 5¼”, 6½” and 8” transducers. The high-frequency sections include a 1" dome tweeter on two models (AC15 and AC25), while the remaining six models incorporate 1" exit compression drivers. 

The 16 ohm impedance of the AC15's & AC16's allows a higher number to be run on a single amplifier channel, and combined with their compact size this makes them ideal for under balcony applications. 

The larger AC18 & AC28, with their 8" drivers and choice of coverage patterns, are often used as front fills. These also have rotatable waveguides giving flexibility to mount them horizontally or vertically.

For more on the AE Series see our in depth series guide 

Point Source - Application Engineered

JBL’s portfolio of point-source speakers includes the larger Application Engineered (AE) series suitable for standalone FOH system specification, and is designed deliver performance that system designers need and audiences demand.

A wide selection of models provide high performance capabilities and proven reliability, and the AE Series has a loudspeaker for just about any application.

Of these, the AM5212 and AM5215 are the most commonly specified in theatre. These are medium-power two-way, full-range models and available in four coverage pattern options. All models have JBL’s patented Differential Drive ® dual 2" voice coil and dual gap woofers; the high-frequency section is a 1.5" exit, 3" diaphragm 2408H-1 compression driver. 

All models have large mouth Progressive Transition™ Waveguides for precise directivity control, and like the larger of the AE Compact models, are rotatable to allow the loudspeaker to be used in either the vertical or horizontal orientation while maintaining the intended horn coverage pattern.

CBT Column Speakers

Where the aesthetics of a column speaker is preferred for a performance space, JBL has the CBT series. 

While the CBT looks like a traditional column speaker, inside it is very different. Constant Beamwidth Technology is a true line-array  where the drivers are arrayed within the cabinet and controlled using passive delay producing a vertically narrow beam of sound. This is much better at controlling the room than the traditionally broad point source box that can propagate in all direction causing reflections and ‘muddying’ the sound from all those nice reflective balconies.

CBT is a great all-round solution for multi-purpose arts venues where the requirements extend beyond that of solely theatre. 

With their wide horizontal dispersion of up to 160 degrees and sleek slim profile design they fit into any venue unobtrusively whilst offering broad, even coverage. 

With their slim compact design the CBT 70J-1 and CBT 1000 look like a standard column speaker but behave like a line array. Both models have a bass extension cabinet which increases the useful output for music reproduction. Add in a couple of a AE series subwoofers and you have a system which is more than capable of amplifying a live band as well as recorded music.  

We find customers are always blown away by what these boxes can do. Like the VTX A8, CBT series are installed in our demo facility; contact us to arrange a visit to give them a listen.

READ: Our Application Guide to JBL CBT Column Speakers

Carole King Musical Tour

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Whatever your space, JBL Professional delivers a fantastic performance with industry leading patented technologies and design. The team at JBL continue to come up with even better ways design and build transducers, developing patents in the process and overcoming challenges such as power compression, heat dissipation, distortion, physical weight and form size. Great thought and detail goes into each cabinets design with the end results offering fantastic clarity, flexibility and performance. Designed to hit every seat in the house, we think JBL is the system for you!