Playing The Angles
Let’s take a look at couple of things that make well-designed line arrays interesting, useful and unique. In contrast to a zonal approach, a quality line array offers improved volume level consistency versus distance.
Now, whether you prefer to envision it in the “cylindrical waveform” description offered by some folks or you just think of it of “as you get farther away the sound gets quieter, but since there are more loudspeakers pointed at you, the volume drop with distance is somewhat counteracted,” the fact remains that line arrays can be set up to project sound over shorter or longer distances merely by altering the vertical angles between the boxes.
A practical feature that the slender line systems offer: their narrow profile is quite easily intermingled with video walls and set pieces. Most people want to see, but they don’t necessarily want to see the sound system (except for a few of us), so having the ability to locate higher output loudspeakers into smaller spaces a strong asset.
The relatively simple two-dimensional rigging that only deals with vertical adjustments not only allows for a high degree of predictability, but is fairly common and typically requires less motor points for rigging in most venues.
The bottom line is that line arrays are simple, practical and predictable, giving them a real-world implementation advantage over other loudspeaker approaches that require multiple, precisely-spaced motor points to provide proper venue coverage.
Still, none of these advantages truly provides line arrays with a hands-down edge. Zonal systems can deal with volume consistency over distance issues by implementing long-throw boxes and utilizing volume shading to compensate and project louder sound to the far away areas.
Further, compact high-volume zonal systems can be incorporated into well thought out set designs, and even flown behind modern video walls that allow sound to pass through.
Well-designed rigging systems for zonal arrays are either in existence or not far off. And generations of cardioid subwoofers offer advances in low-frequency zonal coverage.
Finally, sonic prediction software is not unique to line arrays, and the playing field between the two design theories is fairly even from a technical standpoint.
The Human Factor
So all in all, the choice between approaches should be largely a matter of preference and venue logistics except for one thing: we just happen to be humans, and like many critters that run around this planet, we have ears, and also like many critters, our ears are on the sides of our heads.
This physical placement of our biological hearing devices provides us an extremely accurate high-resolution ability to discern the precise horizontal positioning of sound sources, while only offering a low-resolution approximation of the vertical positioning.
Even our necks are designed with a limited vertical range of motion and a much wider horizontal rotation. At any given moment we are turning our heads or bodies, scanning the horizontal auditory plane.
We enjoy things in stereo. Stereo loudspeakers spaced apart horizontally to maximize the effect. But have you ever wondered why stereo loudspeakers are not placed vertically?
In some apartments and houses it makes sense logistically, yet our ears find horizontally spaced sound sources pleasing and complex, while we have more difficulty discerning vertically spaced sources.
Is this true? Try it and listen.
Have you ever tried to stack a line array on its side? It’s quite interesting, and I’m confident that you’ll find that it typically offers less enjoyable sound.
Take a close look at the various offerings from manufacturers and you’ll find that, usually, there are fixed angles between boxes when horizontally arrayed. This minimizes overlaps in HF coverage and “seamlessly” merges the coverage patterns.
Hey, wait a minute… Isn’t that a zonal design approach? Exactly!