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Crossing The Line: Don’t Overlook Point Source Approaches
Considering whether point source loudspeakers might be right for the tool box...
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It wasn’t too many years ago that most shows were supported with trapezoidal point-source loudspeakers that were either horn loaded or front loaded. There were numerous touring companies providing proprietary loudspeaker systems, some well engineered and some not so well.

Rigging was often an afterthought, and many systems were ground stacked. Companies sprang up that did nothing but design and build aftermarket flying hardware to support both proprietary and manufacturer loudspeakers.

Depending on the combination of rigging and loudspeakers, the desired coverage might or might not be attained; we might or might not be able to get the exact coverage we were looking for, but because of the nature of point-source, a high level of precision was not required. Point and shoot was the order of the day. Eventually most of the manufacturers caught on and started producing fairly capable touring systems with rigging hardware included.

Then came the line array craze. Line arrays only work properly with precise aiming and rigging. All of the components must be vertically stacked and spaced within about one-quarter of a wavelength at the frequency of interest to couple and produce the desired “cylindrical” wave front. The splay between cabinets in the vertical domain has a large effect on how the array behaves. Point and shoot will not work.

The potential to create unwanted lobes and nulls in the coverage pattern requires a fairly sophisticated modeling program to predict the array behavior accurately. Some systems offer amplitude and frequency shading options. They also require rigging hardware that is precisely adjustable in single or even fractional degrees. Inclinometers and lasers have become part of the rigging toolkit.

Out Of Reach
Except for the very largest touring companies the engineering resources to create “home brewed” line array systems are simply not available. The CNC machines necessary to do complex wood and metal work are not in the inventories of most sound companies. Computer programming and software creation are not in most of our skill sets.

There are some prediction software “shell” programs that will accept data from a “one-off” loudspeaker, but the designer must also have the facilities and equipment to provide accurate and complete testing data not to mention paying a licensing fee to the software company. That puts line array development out of reach for most of us.

In many ways this is not a bad thing. From a provider point of view, a variety of quality solutions are available. As front of house mixers, most of us are familiar with many of the commercially produced systems out there, and this makes show advance much more predictable. Rigging is certainly safer. (And the loudspeaker manufacturers like it too!)

But maybe the pendulum has swung too far in the line array direction. Most of the major manufacturers offer many more line array products than large concert-level point-source devices. Few seem to be spending R&D dollars to develop new point source loudspeaker systems capable of doing major show reinforcement.

The bigger touring providers and many regional reinforcement companies have line arrays as their primary systems. Even riders for clubs and small theater shows list line arrays as their preferred equipment. Yet while line arrays are very effective tools for certain applications they’re not a “one size fits all” solution by any means.


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