ProAudio Review - May 2008 - (Page 16) LIVE | Feature by Heather Johnson Line Array Advancements: Designers Speak Out! ine array loudspeaker systems have eclipsed conventional delay and ground-stacked systems in larger venues since the early 1990s. LAcoustics played a large role in bringing the J-shaped designs to the forefront with the Dr. Christian Heil–designed V-DOSC system, which revolutionized large-scale shows by producing full, consistent coverage with smaller boxes, and fewer of them. The system also included modeling software that allowed engineers to customize the system to suit each venue with greater accuracy and efficiency than ever before. From that point forward, loudspeaker manufacturers across the board have produced their own proprietary designs, each putting their own spin on the same basic concept. Recent advancements in everything from materials to design tools have allowed engineers to continually improve the loudspeaker, its components, and a system’s companion software, resulting in better performance and durability with each update. To continually uphold industry standards and keep abreast of changing technology, the R&D department’s role has become even more complex. To find out how some of the industry’s leading design engineers consistently stay at the forefront of live sound technology, we decided to take a tour of their labs. DOWNSIZING THE SYSTEM Once resigned mainly to large venues, line array systems can now be found in houses of worship, small to mid-size music clubs, performance theaters, and even corporate events. To meet this demand, manufacturers have developed compact array systems that offer high performance and consistent coverage in a smaller package. This keeps the design teams on their toes. “The design challenges are the same: constant horizontal directivity is vital, and all of our line arrays have 90 degree or so horizontal dispersion,” says Bill Webb, technical director of Martin Audio Ltd. “As you go down in size, the maximum SPL achievable per box is less. But that’s fine, because you’re not trying to throw as far.” For example, Martin Audio’s W8LM a mini line array enclosure, provides100-degree (-6dB) horizontal mid and HF pattern control and measures 24.41 x 17.5 inches. New materials such as neodymium in transducers and certain plastics help lighten a loudspeaker’s weight. The JBL design team focuses on making lightweight component transducers. “JBL’s patented Differential Drive technology coupled with neodymium magnets, with two voice coils in every loudspeaker, enables us to offer loudspeaker components that are one-third the weight of Meyer Sound Principal John Meyer traditional components from other sources and also have increased output capabilities due to the dual voice coil technology,” says David Scheirman, JBL’s Vice President of Tour Sound. “We also use a lightweight engineered composite wood product called PlyMax, which lets us offer very strong, rigid, robust enclosures and reduced weight compared to traditional materials.” “Some of the integrated systems that we’ve designed have self-contained DSP and amplifiers, so you have these high efficiency amps that are super-small, don’t really generate a lot of heat, and are super lightweight,” says EAW principal engineer Nathan Butler. “For the EAW NTL720 we have a 1,500-watt amplifier that weighs just over nine pounds. Ten or 15 years ago, that would have been unheard of.” Looking at the enclosure, the “baby” NTL720 and NTL730 line array modules both feature side-mounted LF drivers, another space-saver. “We basically achieved the same beam width as we would if those woofers were firing forwards, but if they were firing forwards the physical width of the box would be larger,” says Butler. Rigging systems can be built from aluminum instead of steel, while new analysis software allows designers to model stress failures, which allows them to maximize a component’s strength with the least amount of material. That’s especially important in the U.S., where gas prices have reached an all-time high, and therefore production companies aim to take as few trucks on the road as possible. “Truck-pack is always a consideration when designing new equipment for the professional sound industry,” says Tim Roger Waters on Coachella 2008’s main stage —left and right main PA arrays each are comprised of 15 L-ACOUSTICS V-DOSC enclosures with three dV-DOSC hung below 16 | ProAudio Review | May 2008 www.proaudioreview.com http://www.proaudioreview.com
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