Column Line Array Loudspeakers
Oct 10, 2012 2:43 PM, By Mark Johnson
Tried and true, the venerable column array is a design that many of us have cut our teeth on. While the modular, large-scale systems have been recently grabbing all of the headlines, column arrays have quietly made a resurgence. A staple product in school auditoriums and community centers in the 1960s and onward, advancements in technology have allowed these workman-like, blue-collar loudspeakers to fit into a variety of useful and interesting applications.
The behavior and advantages of a line source are well documented, starting in 1957 with Harry Olson who applied the concept of a line array to produce a system of vertically aligned drivers providing a coverage pattern that was wide horizontally and narrow vertically. The beauty and appeal of the line source is that you can get a rather well behaved loudspeaker, insofar as coverage is concerned, in a relatively small or low-profile enclosure.
One of the most popular column arrays was Shure’s Vocal Master, introduced at the NAMM show in 1968. Not only was it a popular touring system for the time, the Vocal Master was also installed into many schools and houses of worship, as well as in the London Palladium and the Rainbow Room at Rockefeller Center for use by acts such as Duke Ellington and Benny Goodman. As hinted at by the name, the strength of the Shure column array was reproducing frequencies in the vocal range. Also, since the length of the array influences the coverage angle at low frequencies, (longer provides more directional control) in the early days, practical sizes were limited in frequency response to the vocal region. Vocal intelligibility was and still is a main selling point, though some models offer auxiliary subwoofers or systems where the low frequency drivers have the ability to provide a more extended low end.
Another benefit of line array systems is that they exhibit only 3dB loss per doubling of distance versus 6dB of loss in a conventional loudspeaker system, which provides a system with increased throw distances and the variation between near and far field is minimized. That, coupled with the well-defined vertical coverage, made them a natural for installs requiring vocal amplification in potentially reverberant spaces. On the surface, many of the column arrays available today look just like the columns in the days of old. However, incremental advancements in loudspeaker driver technology—combined with self powering and DSP—matched with snazzy industrial design have delivered systems with far superior frequency response, better power handing, higher SPL, asymmetrical coverage, and more defined pattern control. Some models even provide adjustable and steerable pattern control. Let’s see what the market place has to offer. Also check out the manufacturers’ websites as there are often additional models, features, and accessories too numerous to include in this showcase.
The Alcons Audio QR36 modular two-way column loudspeaker comprises six 6.5in. neodymium low-frequency drivers and two 18in. pro-ribbon high-frequency drivers. The frequency response is 53Hz to 20kHz, and the nominal program SPL is 129dB. The system features coverage of 90 degree horizontal and the vertical dependent on the array length. A single module is 39.6in. tall, 14.in. wide, and 9.3in. deep. Modules can be easily combined. In order to derive maximum performance from the system it is recommended that that it be used in conjunction with the ALC controller-amplifier.
Employing 12 2.25in. drivers mounted in a powder-coated aluminum enclosure, the Bose Panaray MA12 mid/high modular line array provides 145-degree horizontal coverage and a single MA12 module provides a vertical coverage of 20 degrees. The frequency response is 100Hz to 16kHz, though low frequency response can be extended with the addition of the MB4, MB12, or MB24 modular bass loudspeakers. The maximum peak SPL is 119dB.
A company steeped in the history of the commercial audio industry, Bogen Communications’ SCW35 provides a maximum SPL of 105dB @ 1W input measures at 4ft. on axis. The frequency response is 70Hz to 16kHz with coverage of 25-degrees vertical and 120-degrees horizontal. Six 6in. drivers are mounted in an enclosure that is 42in. high x 9.5in. wide x 6in. deep.
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