5 buying tips, a roundup and the almost 80 year history in the making. The steered array loudspeaker technology has caught up with theoretical promise.
By Frederick J. Ampel
August 16, 2012
point, as each product’s design and implementation is different, and what really matters is the sum of the parts and the performance they provide, not the individual details.
The low-frequency limit for any array is a combination of array size, design and software/hardware. Generally speaking the taller (longer) the array is, the lower the frequency at which pattern control and steering can be achieved. You must consider what your realistic low-frequency requirements are for the particular application. Some products offer additional low-frequency add-one units or subwoofer companion products that can be used to deal with extended LF requirements.
How the digital control software/hardware and its interface, DSP processing and power amplification are put into practice will vary within the companies listed. No one way to get to the end result is better than any other. What matters is the total performance produced and what will best suit your specific needs and budget.
The five key things to consider when looking at applying these innovative and very flexible products to your situation are:
- How far away from the loudspeakers mounting position do you need to produce an intelligible signal. This will let you select the general size category of array you will need.
- Do you need to produce full range music and speech or just speech? Full range applications generally require the use of add on LF units or other products to achieve the low-frequency bandwidth required. Remember, low frequencies radiate omnidirectionally — that is, you will not be able to produce the kind of pin-point beam steering you can get above 1 kHz with these products.
- The more LF energy you produce in a reverberant or reflective space, the more likelihood there is of masking and other undesirable affects. A build up of LF energy can ruin the performance of any of these products, so careful attention must be given to this issue.
- When multiple arrays are to be used such as in a long narrow space, you must make sure that the distance between units are calculated accurately so that you can achieve even and seamless coverage. This requires plotting the coverage from array to array to insure appropriate overlap and beam steering angles and aiming.
- These products function best when placed in a corner or on a structural column, wall or other boundary surface. You must consider this placement criteria when planning array locations and coverage.
The capabilities presented by this product category can provide you with a powerful tool in your arsenal of solutions and often get results when nothing else will work. 
The References
1) Wolff, I., and Malter, L., Jour. Acous. Soc. Amer., Vol. 2, No. 2, p. 201, 1930. The seminal work on line arrays
2) Olson, Harry. F. 1st ed., p.25, D. Van Nostrand Company, Inc., New
York, 1940
3) Beranek, Leo, Acoustics, first edition, McGraw-Hill,1954
4) Klepper, David and Douglas Steele, Presented October 15, 1962 at the 14th annual fall convention of the Audio Engineering Society, New York
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