At PLASA 2012, HARMAN’s JBL Professional is introducing the VTX-LZ-K Laser Accessory Kit, which facilitates the alignment of JBL VTX Series line array loudspeakers for optimum performance and audience coverage.
The VTX-LZ-K includes two VTX-LZ laser units and one rechargeable VTX-LZ-PS power supply. The VTX-LZ employs a Class 3R green laser (less than 5 mW, 532 nm wavelength) and is approximately 20 times more visible than a red laser for maximum visibility over long distances indoors or outdoors. The VTX-LZ laser units connect to the VTX-LZ-PS power supply by means of a standard XLR cable and multiple lasers can be daisy-chained (up to 10 units powered from a single power supply).
All VTX-LZ-K components feature aluminum and high-impact plastic weather-resistant construction for long-term durability. The laser units are factory-calibrated, weather-resistant and feature fan-cooling and on/off cycling for extended laser life.
VTX-LZ laser units attach to the VTX enclosure suspension frame and are secured using a quick-release locking pin. Lasers can be mounted on either side of the enclosure by changing the orientation of the VTX-LZ mount tab and since the laser is centered on the middle of the enclosure, it provides an accurate site angle reference in accordance with JBL Line Array Calculator II (LAC II) software predictions.
“Precise VTX V25 line array vertical pattern control requires precise focus to achieve optimum coverage and the VTX-LZ-K Laser Accessory Kit is a valuable time-saver that helps to ensure the best possible setup of a JBL VTX line array system,” said Paul Bauman, Senior Manager, Tour Sound for JBL Professional. “Multiple VTX-LZ lasers can also be used to assist with microphone placement for more detailed system measurement as part of the calibration and tuning process and this has been specifically designed into the workflow of recently-released JBL HiQnet Performance Manager software.”
When mounted on the top enclosure of a VTX line array, the VTX-LZ laser provides a visual reference to confirm the on-axis vertical site angle of the array while also providing an azimuth indication so that relative horizontal pan angles can be matched for FOH left-right arrays. With reference to LAC II software, the normal installation procedure is to attach a tape measure to the lower front corner of the bottom VTX enclosure as a reference for setting array trim height. Once the array trim height is set, the front motor is turned off, the VTX-LZ is turned on and the rear motor is manipulated to adjust the array site angle while visually referring to the laser to ensure that top enclosure is pointed at the rear of the desired audience location.
For advanced system tuning, multiple LZ lasers can be deployed to serve as site angle references for individual array circuits, assisting in physical measurement microphone placement to correspond with virtual measurement microphones shown in LAC.
Using JBL HiQnet Performance Manager control software and with reference to measured spatial response, circuit level gain shading and JBL Line Array Control Panel (LACP) frequency tapering adjustments are performed as a first step in system tuning. This initial step is referred to as array calibration and JBL LAC II / LACP simulations provide a starting point. For the actual real world installation, VTX-LZ lasers mounted on array circuits can be used as a reference for microphone placement to verify and further refine the starting point gain shading and tapering parameters that were pre-determined in JBL LAC II / LACP and Performance Manager.
Once SPL and frequency response has been optimized on a circuit level, global equalization can then be applied to the entire array to compensate for room-related effects. For this step, array equalization can be based on the spatial average of all measurement microphones that were placed throughout the audience area with reference to VTX-LZ laser aiming locations. This patented approach to system measurement and tuning has been specifically designed into the workflow of Performance Manager (US patent 2008/0170729).