The new JBL
VTX-LZ-K laser kit includes
two VTX-LZ laser units (right), rechargeable VTX-LZ-PS power supply (top left) and AC adapter (lower left). |
LONDON, United Kingdom – 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 rugged 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 good
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).
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