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Meyer Sound / JM-1P The high-end JM-1P from Meyer sound supplies rigging for arraying in either horizontal or vertical orientations.
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MackIe / HDA system HDA is a scalable, arrayable solution— ideal for portable PA users that want their system to grow as needed.
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QSC / KLA12 The rear panel of the KLA12 from QsC provides simple, self-explanatory controls for array optimization along with facilities for remote level control.
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JBL / VRX series Two JBL VRX932LA cabinets may be pole-mounted over a VRX918 subwoofer for a high-power portable system.
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Renkus Heinz / CfX-101 series with grilles cut away for illustration only, this photo shows the low-frequency driver and high-frequency waveguide configuration of the CfX-101 series from Renkus Heinz, fl own beneath the companion subwoofer.
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Vertical Coverage - Adding cabinets to a line array results in narrower vertical coverage (but longer throw), where adding more cabinets to a constant curvature array broadens the vertical coverage. Based on an illustration courtesy of QSC audio.
When is a line array not really a line array? Well, when it's curved, of course.
You've probably noticed the ads for the new generation of curved array loudspeakers, and maybe heard a system in action. They've become quite popular, and deservedly so. But they've also introduced some confusion as to how they operate and when they should be used.
Since we're all so accustomed to the catchphrase “line array,” you might hear these systems referred to as “curved line arrays.” But that's a misnomer—an oxymoron, really—because they function acoustically in a different manner than a straight line array. As a consequence, curved arrays are deployed differently because they function acoustically like “modular point source loudspeakers.” (In fact, that's what one manufacturer calls its product line.) Technically they are termed arcuate arrays (though we know of only one manufacturer who uses this term), but here, we'll use the most common reference: constant curvature arrays.
To understand the difference, let's review how a straight line array works. In a simplified nutshell, a straight line array is designed to throw the sound further by allowing constructive reinforcement of the sound waves perpendicular to the vertical axis of the array. Sound waves combine constructively for a longer throw, but at the same time the vertical coverage angle is narrowed. The effect is frequency dependent, of course: for lower frequencies (longer wavelengths), a longer array is required to produce the same directional effect.
Functionally different
Constant curvature arrays function quite differently. Here, the idea is, as much as possible, to avoid constructive/destructive interference between loudspeakers in the array. Instead, the vertical coverage patterns in the mid-high frequencies are separated, with each individual loudspeaker throwing its own distinct “wedge” of sound out to the audience. Each array cabinet is designed for a wide horizontal pattern (usually 90 to 120 degrees) and a narrow vertical pattern (15 to 20 degrees). Unlike modular line arrays, the cabinets are designed to connect directly to one another, with no splay angle between. Essentially, the splay of the internal components is fixed by the curvature of the array.
This design greatly simplifies array configuration, when compared to conventional line arrays. To determine your vertical coverage, simply multiply the nominal vertical coverage per cabinet by the number of cabinets. If a single cabinet is 100 degrees horizontal by 15 degrees vertical, then two would be 100 x 30 and four would be 100 x 60.
That brings up the question, “Why not simply use a point source loudspeaker with the same desired coverage pattern?” In some cases, granted, that might make more sense—and save some money. But in many other cases, you might want more power (and more headroom) than you can get from a single point source cabinet. In this case, the constant curvature array becomes a “point source on steroids,” delivering more power by virtue of more drivers pumping out higher acoustical levels.
The flexibility advantage
Also, in portable church or touring band scenarios, the constant curvature array gives you more flexibility. One venue may call for, say, two array cabinets, pole-mounted on a subwoofer, where later you might need four flown cabinets for more power and increased vertical coverage. It's a nice compromise because you gain the flexibility of a modular line array but with far simpler rigging and electronic optimization. It's neither a point source nor a line array, but a hybrid combining attributes of both.
If you want plenty of power over a wide area, but don't need to throw a long distance, constant curvature arrays are a good choice.
Regarding the array optimization, yes, you do need to make some adjustments for the number of cabinets in the array to maintain an even response. Also, in some cases you'll want to taper off the high-frequency level in the bottom cabinets facing the nearest part of the audience. In most self-powered systems, this is easily accomplished with rear-panel knobs or dipswitches. No computer required.
In sum, for applications where you want plenty of power and need to cover a wide area—but don't need to throw a long distance—constant curvature arrays are a good choice. And if you look at the architecture of many contemporary churches, you can see why it's often such a great fit.
All loudspeakers in the following round up have a generic similarity in cabinet shape, and all except the last two have a wide horizontal pattern coupled to a narrow vertical dispersion. Most are self-powered, but a few are passive and would best be bi-amplified using appropriate digital processing for array compensation. In addition, most offer pole-mounting atop companion subwoofers, usually with dual-angle, pole-mount cups to allow either straight-on or slight down-tilt (15 degrees typical). Though all are based on the same acoustical principles, the power output levels, costs and available options vary considerably.
Passive options
Though only a few passive options are available, they are worth considering, particularly if your church already has at least some of the appropriate amplifiers and digital loudspeaker management systems. Cost per array loudspeaker runs in the $1,400 to $2,200 range.
JBL's popular VRX line offers two passive choices. The VRX928LA houses a single eight-inch woofer and two one-inch compression drivers, while the beefed-up VRX932LA incorporates a 12-inch woofer and three 1.5-inch compression drivers. All drivers are built with Neodymium magnets for high power and optimum efficiency. Two array cabinets can be pole-mounted on the companion subwoofer (VRX915S for the VRX928LA or VRX918SD for the VRX932LA), or up to six may be flown beneath the subwoofer using the optional rigging frame. Both systems are available in either black or white.
The JFL-213 from EAW takes a different tack, with dual 10-inch woofers working in tandem with three center-mounted 1.75-inch compression drivers. Two modules may be pole-mounted, and up to five flown under the optional flying frame. The JFL-213 may be driven by a single amp channel using an internal crossover, though EAW recommends bi-amplifying the system and using the UX Series processor which has presets for optimum performance in various array configurations.
The CFX101-LA8 is the base unit of the option-laden CF/CFX Series of “Modular Point Source Array” systems from Renkus-Heinz. Each low-mid cabinet includes a 10-inch woofer and dual one-inch compression drivers, both with neodymium magnet structures. A proprietary Tuned Conic Diverter waveguide matches the curvature of the wavefront from the horn to the curvature of the array. It may be pole-mounted or flown in conjunction with the companion CF-15SX passive subwoofer.
Self-powered systems
Again, the passive systems above are good options if you already have appropriate amps and DSP, but in most other circumstances, you're probably better off stepping up to the self-powered versions. Costs for the array cabinets in this section range from about $1,800 to a bit over $3,000 in a fully loaded, networked version.
If you like the VRX Series from JBL, the 12-inch woofer version is available with the Crown Drivepack amplifier module, producing 1,750 watts of peak power. A built-in, DSP-based array configuration selector provides array-shading options appropriate for array size and use. For some unknown reason, however, this powered version and its companion VRX918SP powered subwoofer are not available in white.
Renkus-Heinz takes the same concept a step further with its CF101 Series, offering a dizzying number of built-in amplifier options with different power levels (200 W and 500 W), the latter available with or without the company's proprietary RHAON networking. This Chinese food menu approach keeps a base powered unit in line with the competition's pricing, but also allows configuration of more powerful and sophisticated, high-end installed systems.
Moving into the powered-only category, we have Mackie's value-priced HDA system. Each cabinet houses a 12-inch woofer and dual 1.7-inch compression drivers, with the lows coupled to a 500 W Class D amplifier and the highs to a 100 W amplifier. The on-board DSP engine supplies acoustic correction, transducer time alignment, and phase correction. Arrays can be flown using integrated rigging points, or short arrays may be pole-mounted on the companion HD1801 18-inch powered subwoofer.
The KLA Series from QSC has attracted attention with its sleek design, easy-up rigging system, and intuitive rear-panel array optimization tools. Each KLA12 array loudspeaker includes a 12-inch woofer and a 1.75-inch compression driver along with two channels of 500 W power amplification. A proprietary ArQ (Arcuate Equalization) processor allows the operator to optimize an array of any size with the click of a dial. The rear panel also includes an attenuator and a remote gain control connector. An auto power down feature makes it a “green” choice, and here you do have a choice of black or white in both the KLA12 and the companion KLA181 18-inch subwoofer.
High-end, dual orientation
Finally, we'll footnote a couple of systems that are based on the same acoustical principles as those above, but target somewhat different applications: the Arcs II from L-Acoustics and the JM-1P from Meyer Sound. Compared to the others, both are larger, far more powerful, considerably more expensive, and designed for optimization using highly sophisticated, computer-based tools. Essentially, these are for very high-end, large church installs (as mains or as fills supporting their respective company's line arrays), or for touring concert sound. Both provide rigging points for either horizontal or vertical arraying, which means that you could construct a “doughnut” center array with 360-degree coverage, if you desired.
The Arcs II is built around a 15-inch neodymium LF driver and a three-inch neodymium HF compression driver, together producing an impressive 140 dB peak SPL. This is a passive system, designed specifically for bi-amplification and resident optimization exclusively by L-Acoustics own LA8 DSP amplifiers. The vertical pattern is an asymmetrical 60 degrees, with a downward tilt that is handy for flown horizontal arrays but might be awkward in vertical array deployments.
Meyer Sound's JM-1P is a self-powered system, also with neodymium drivers: a 15-inch LF and four-inch diaphragm HF driver. The two-channel Class AB/H amplifier produces 2,250 W for an acoustical output of 138 dB SPL peak. The spec sheet gives a coverage pattern on 20 degrees horizontal by 60 degrees vertical, but in this case it is symmetrical, making it adaptable for vertical arrays that would benefit from the tighter horizontal pattern.
Dawn of the hybrid era?
Hybrids automobiles are all over the roads these days, saving a lot of gas. I expect we'll see a lot more of these hybrids of point source and line array loudspeaker systems in churches, saving time and hassles while producing excellent sonic results.
