JBL Professional VRX928LA Line Array Loudspeaker System User Manual

Product Overview

The JBL Professional VRX928LA is a high-performance line array speaker system designed for venues requiring outstanding sound coverage without the extensive throw of larger line arrays. It is a compact 8-inch two-way speaker system, weighing only 28 lbs, making it highly portable and easy to integrate into various setups.

Key features include Constant Curvature waveguide technology for consistent sound, dual high-frequency drivers for superior performance, and enhanced amplitude shading capabilities for consistent volume levels throughout a room. It is suitable for small concert venues, DJ setups, houses of worship, rental companies, and professional PA systems.

Figure 1: Main view of the JBL VRX928LA Line Array Loudspeaker System, showcasing its overall design.

Physical Description and Connections

Understanding the physical aspects and connection points of the VRX928LA is crucial for proper setup and operation.

Figure 2: Front view, highlighting the protective grille and JBL branding.

Figure 3: Side view, showing the compact profile and integrated rigging points.

Figure 4: Rear panel, detailing the input connectors and the Array Configuration Selector switch.

The rear panel (Figure 4) provides access to the audio input connectors and the Array Configuration Selector (ACS) switch, which allows you to select between passive and bi-amplified operation modes and adjust the high-frequency output level.

Setup and Installation

The VRX928LA offers versatile mounting options to suit various applications, whether used individually or as part of a larger array system.

Mounting Options:

• Tripod Mounting: Individual VRX928LAs can be mounted on a standard speaker tripod stand (e.g., JBL SS2-BK) using the integrated dual angle pole socket.
• Pole Mounting over Subwoofer: For extended low-frequency response, the system can be mounted over a compatible subwoofer (e.g., VRX915S) using an adjustable satellite speaker pole (e.g., JBL SS3-BK or SS4-BK).
• Suspended Line Array: Up to six VRX928LA speaker systems can be suspended in a single array to achieve a nominal vertical coverage of up to 90°. This configuration requires the JBL VRX928LA-SMAF array frame (available separately). The integral hardware allows for secure locking of array elements. For applications requiring a sharp downward aim, a second Array Frame can be installed at the bottom of the array to serve as a pull-back.
• Ground Stacked Array: Multiple units can be ground stacked, often in conjunction with subwoofers, for setups where suspension is not feasible or desired.

Figure 5: Multiple VRX928LA units configured as a suspended line array, demonstrating the system's scalability and rigging capabilities.

Figure 6: Three VRX928LA units arranged in a curved line array, illustrating the Constant Curvature waveguide design for seamless sound integration.

Operating Instructions

The VRX928LA can be operated in either passive or bi-amplified modes, externally switchable via the rear panel. This allows for flexibility in system configuration and amplification.

Crossover Modes:

• Passive Mode: In this mode, the internal crossover network manages the frequency distribution to the low and high-frequency drivers. This simplifies setup as only one amplifier channel is required per speaker.
• Bi-amp Mode: This mode allows for separate amplification of the low-frequency (LF) and high-frequency (HF) sections of the speaker. This provides greater control over the sound and can lead to improved dynamic range and clarity, requiring two amplifier channels per speaker.

Array Configuration Selector (ACS) and Amplitude Shading:

The VRX928LA features an Array Configuration Selector (ACS) on the rear panel. Amplitude shading is a technique that adjusts the coverage pattern of a loudspeaker array by modifying the relative acoustic output of some of the devices in the array. This feature enables users to adjust the output to achieve consistent volume levels throughout the listening area, ensuring an optimal audio experience for all attendees.

In passive mode, the ACS can be used to adjust the HF output level. For example, a -3 dB setting might be used for speakers covering closer audience areas, while a +3 dB setting could be applied to speakers covering more distant areas, or to compensate for low-frequency build-up resulting from mutual coupling of multiple woofers in an array. In bi-amp mode, the amplifier output levels for LF and HF sections should be adjusted accordingly to achieve desired shading.

Maintenance

To ensure the longevity and optimal performance of your JBL VRX928LA loudspeaker system, regular maintenance is recommended.

• Cleaning: Periodically wipe down the exterior of the speaker with a soft, dry cloth. Avoid using abrasive cleaners or solvents that could damage the finish.
• Inspection: Regularly inspect all cables, connectors, and mounting hardware for any signs of wear, damage, or loose connections. Ensure all screws and bolts are securely fastened, especially for suspended applications.
• Storage: When not in use, store the speakers in a dry, temperate environment, protected from dust and extreme temperatures.
• Professional Service: For any internal issues or complex repairs, it is recommended to contact authorized JBL Professional service centers. Do not attempt to open the speaker enclosure yourself, as this may void the warranty and cause further damage.

Troubleshooting

This section provides basic troubleshooting steps for common issues. For more complex problems, refer to the official JBL Professional support resources.

Specifications

Detailed technical specifications for the JBL Professional VRX928LA Line Array Loudspeaker System:

Note: Some specifications are compiled from the product description and official documentation.

Warranty Information

The JBL Professional VRX928LA Line Array Loudspeaker System comes with a Limited Warranty. Specific terms and duration of the warranty may vary by region and retailer. Please retain your proof of purchase for warranty claims.

Optional protection plans are available for extended coverage:

• 2-Year Protection Plan
• 3-Year Protection Plan
• Complete Protect (monthly billing option)

For detailed information regarding warranty terms and conditions, please refer to the warranty card included with your product or visit the official JBL Professional website.

Customer Support

For further assistance, technical support, or service inquiries regarding your JBL Professional VRX928LA loudspeaker system, please contact JBL Professional customer support.

You can find more information and support resources by visiting the official JBL Professional Store on Amazon or their official brand website.