Current Trends: Line Arrays

by Michael Hoddy | Sep 12, 2013

 

One of the current trends in sound system design is the use of line array speaker systems in many concert and installation applications. If you have been to any recent concert in a larger theater, arena, stadium, or outdoors, chances are excellent that you have seen and heard a line array system in action. This trend has, not surprisingly, had a spill-over effect into the House Of Worship field, where “line array” has become almost a marketing buzzword synonymous with the latest in cutting-edge audio technology, and a cure-all for acoustical challenges everywhere. For a church investigating a new audio system, how does one separate the facts from the hype?

First of all, a line array is simply a tool, and like all tools, it can be a great tool when used properly and a very poor tool in the wrong application or the wrong hands. As an illustration, you can buy the very best table saw on the market, but if the woodworking job you are doing really requires a miter saw, you have the wrong tool, and even if you have a great table saw, the results will not be the right quality, or they will take a lot more effort to achieve. The same is true with line arrays.

Secondly, line array technology is not new technology at all. If you have been to an older Roman Catholic, Episcopal, or similar church with tall column-like speakers mounted left and right of the platform or altar area, you have seen line array principles at work, albeit in a much more primitive form (Date the technology).

What does a line array do? Quite simply, it is a speaker array technique that exploits the fact that speaker drivers arrayed in a vertical line tend to exhibit vertical pattern control, and the stability of this pattern increases the longer the line. In plain English, this means that a line array has the ability to “throw” sound longer distances, and to maintain more consistent sound levels over distance within that “throw.” Both the distance of the throw and sound level consistency within it are dependent on the vertical length of the line array. And while line arrays have vertical control over the projected sound coverage, they disperse sound horizontally over a wide area. This can be helpful in wide rooms, but detrimental in narrow rooms.

What does this mean for your church? In our travels, we have seen a few well-implemented line arrays, and quite a few poorly-conceived ones which are either the wrong tool for the application, or which have been designed and deployed poorly. So how can you discern if this “tool” may be right for you? Here are some general criteria which can help:

1. Room Proportions:

  • Deep and Wide: Generally speaking, a conventional spaced-pair (left-right) line array system requires a relatively wide room to be effective, and for the line array characteristics to be of much use, the room should also have a reasonable amount of depth- around 75 feet or more. Higher ceilings (at least 18 feet or so) make it much easier to deploy a line array solution effectively. Line arrays are generally neither practical nor beneficial in smaller rooms.
  • Deep and Narrow: A single, center-hung line array may be a useful tool in a long narrow room for speech reinforcement, but such a setup is generally less desirable for music reinforcement. A spaced-pair (left-right) line array system will generally not function as well in a narrow (around 60 feet or less) room as a more conventional solution because of cancellation and acoustical interference in the horizontal domain between the two arrays.
     

2. Acoustics

Line Arrays are great for larger, and/or more acoustically live environments where the introduction of delay speakers is not practical or desirable. Shallow rooms (short depth from front to back) do not take full advantage of the line array’s ability to project sound in a controlled manner vertically, and while the solution may sound fine from a performance standpoint, a properly-conceived line array costs more than other more conventional and equally workable solutions in such rooms.

3. Deployment and Installation

  • 2 to 4, Needs Some More: One of the most common scenarios we encounter in churches is a “line array” which is comprised of 2 or 3 speaker cabinets per side. It is critical to understand that it takes a good number of vertically-arrayed speakers to begin exhibiting line array characteristics- a typical industry rule of thumb is at least 5 speaker cabinets per array. These smaller 2 or 3-cabinet arrays may help to cut costs, but they are not functioning line arrays and very often do not have adequate vertical sound coverage for the rooms they are placed in, creating dead spots at the very front or very rear of the seating area in the room.
  • Hangin’ Tough: Line arrays must be hung at the proper distance from each other and from the seating area. Too far apart from each other, and there are holes in the sound coverage in the front center of the room. Too close together, and there can be cancellation or acoustical interference between the arrays. Too close to the seating area, and the arrays often cannot cover the front rows of seating nearest them. Line arrays really function best in rooms with plenty of depth and adequate ceiling height, giving  the best potential for optimal placement and deployment.
     

4. Cost Versus Performance

There may certainly be exceptions, but line arrays are almost never the best option in terms of balanced cost versus performance in smaller (seating less than around 250) rooms. In midsized applications where line arrays begin to become a viable option, a properly-designed line array solution generally costs more than a more conventional solution, and whether the results are worthwhile depends very much on the characteristics of the room it is being placed in. In larger venues, and only in larger venues, the costs may begin to even out more as the simplicity of a larger line array begins to outweigh the complexity it would take to achieve the same results in terms of sound levels and even coverage with a more conventional approach using many speakers and multiple arrays.

5. A Note About Curvilinear Arrays

There are several speaker systems, such as JBL’s VRX-series and QSC’s KLA-series, which are technically “curvilinear arrays.” A curvilinear array looks a lot like a line array, with vertically-stacked cabinets, but is usually comprised of 2 to 4 speaker cabinets per array. The speaker series mentioned are both high-quality modular solutions which are often a great option for customizing vertical sound coverage in shorter, wide rooms, but they are not line array designs and cannot exhibit line array characteristics. Beware the integrator or sound company which attempts to market them as such!

So is a line array the best solution for your house of worship? Hopefully this article has begun the conversation for you and given you some good questions to consider. We’d love to help you continue that conversation and begin to answer those questions. Feel free to contact us for a free, no-obligation consultation!

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