Peer Review- JBL Vrx932la And Vrx918sBrian Bednar reviews the JBL VRX932LA line array and VRX918S subwoofer. 9/22/2005 6:51 AM Eastern
Peer Review- JBL Vrx932la And Vrx918s
Brian Bednar reviews the JBL VRX932LA line array and VRX918S subwoofer.
Product: VRX932LA line array and VRX918S subwoofer
Price: $2,399 (VRX932LA); $1,399 (VRX918S)
Company website: www.jblpro.com
Plus: Extremely portable line array; high power handling and wide frequency response; easy to pole mount
Minus: Compact rigging storage pins; pole mount attachment size on subwoofer; subwoofer response
WHILE INTENDED for smaller venues than JBL's larger VerTec series line array loudspeakers, the VRX932LA Constant Curvature Line Array is designed and built to the same high standards and uses the same advanced, concert-proven drivers. The VRX932LA delivers extraordinary power handling, clarity, and flexibility in an attractive, easy to handle, and affordable package that's perfectly suited for pro AV installations and rental & staging applications.Design
In large venues, the very narrow vertical coverage of a VerTec line array enclosure allows a lot of acoustical energy to be projected to distant listeners. But in smaller venues, the narrow vertical dispersion means a large number of VerTec enclosures will be required to provide the needed vertical coverage. The VRX932LA is designed with wider vertical coverage (15 degrees), so fewer speakers are required in small- to moderate-sized venues.
JBL's Constant Curvature high-frequency waveguide mounts three compression drivers on a continuous arc, enabling the drivers to work together acoustically as if there were a single driver. As additional enclosures are added to the line array, the continuous arc is extended with all of the drivers working together as if they were one. The Constant Curvature Array technology provides good signal coherence and clear high-frequency sound quality regardless of the configuration.
To keep weight at a minimum, the VRX932LA features JBL's Differential Drive woofers with light-weight neodymium magnets. This design also eliminates the massive steel top plates and back plates found in the motor structures of conventional loudspeakers.
The VRX918S is a compact, high-power suspendable subwoofer system containing a 2268H neodymium magnet, Differential Drive, and an 18-inch woofer in a front-loaded, vented enclosure. Designed specifically for use in arrays with the VRX932LA line array speaker and VRX-AF frame, it may also be used in arrays consisting entirely of VRX918S subwoofers.
Equally at home in ground stacked applications, the VRX918S is equipped with a top-mounted, threaded 20 mm socket for an optional SS4-BK pole. This adjustable height pole can be used to support speakers that weigh up to 100 pounds and are equipped with standard 35 mm pole sockets. The threaded socket minimizes buzzing and rattling and ensures that the pole will be secure and straight.
JBL's integral rigging hardware for the VRX932LA and VRX918S allows each unit to be securely locked to one another and to the array frame by swinging a hinged bar into place and securing it with the included quick release pins. For permanent installation applications, a VRX array may be suspended using M10 eyebolts. For smaller venues, or performers working alone, the compact size and portability of the VRX932LA allow it to be utilized as a single cabinet, two-way utility speaker system.Performance
Running in passive mode, I immediately noticed that the vertical pattern of the VRX932LA performed as predicted. I began moving my head over the horn flare and noticed the amazing control of the high-frequency range. Stepping back a few feet, I moved the cabinet side to side and dipped it up and down. The horizontal coverage continued to show the same frequency response while the vertical coverage dipped in and out of my coverage area. The high-frequency horn flare proved to be incredibly accurate in controlling the vertical pattern.
Next, I turned to bi-amping the VRX932LA using a dbx Driverack 480 for processing and a Lab.gruppen fP6400 amp to power the system. I used the processor settings JBL provided to program the Driverack. At first I noticed that the VRX918S seemed to be lagging behind the two VRX932LAs. The sub range seemed very subtle and didn't reproduce as much as I expected, perhaps because the ratio of mid-high was too great. I worked more with the subs and created more output by bringing up the output of the processor.
Moving on to the VRX932LAs, I began to run some tests by switching the ACS switch on the input panel of the top cabinet to project the high frequencies. This is a wonderful feature that helps keep the SPL very even in the high-frequency range from the front of the speaker system to the rear 40 feet away, without the need to purchase extra amplifiers and processors. The low-end response seemed very natural, defined, and balanced. The cabinets produced a very rich, full response, which is ideal for voice applications.
Using the SS4-BK pole mount to attach the two VRX932LAs onto the sub, I placed the cabinets into the very forward pole socket. Another great feature is the ability to aim your arrays without placing wood blocks under the subs or tripods. However, the pole mount on the sub seemed a bit weak. The sub top mounting plate uses a M20 female thread and the pole uses a M20 male. Each is only about 3/4-inches wide compared to standard pole mounting sockets that are about 2 inches wide.
Next, I placed a B&K microphone 1 meter from the enclosures and ran an analyzer test using SIA SMAART to examine the frequency response of the enclosure. True to form, the system measured what the JBL spec sheet quoted, which was 75 Hz to 20 kHz ±3 dB.Value
While the VRX932LA's list price of $2,399 may seem a bit expensive for a tripod speaker to some, its performance is well worth the money. Compared to other pole-mounted speakers, I don't know of any others that control pattern coverage and unwanted room reverberance as well as the VRX, in addition to the ability to fly multiple enclosures in a lightweight package. JBL's ACS system will also help reduce system cost in the long run, eliminating the need to purchase multiple amps or processors. For church or theater applications, the size of a flown array will help address sightline issues, while the light weight will help reduce rigging problems in buildings where there are load limit constraints.
Brian Bednar is chief engineer at RCI Sound Systems, a Washington D.C.-based sound reinforcement company. He can be reached at firstname.lastname@example.org.