Sound System Design Essentials Coniston
Grange Over Sands
Sound System Design Essentials
Source: PRO AV Magazine
Publication date: July 1, 2007
By Pat Brown
Most audio pros know that loudspeaker data can be used to predict important aspects of a sound system's performance at the drawing board stage of a project. But it's also possible to extend the concept to array design.
The array prediction process is embraced by some, shunned by others, and amazingly accurate when done within the limitations of data and prediction methods.
We need arrays because many venues cannot be covered adequately with a single loudspeaker. Yet implementing multiple loudspeakers can introduce a lot of problems. Ask any RF engineer what happens when you radiate radio waves into a space from two different antennas operating on the same frequency. His likely answer: “Drop outs. Don't do it.”
The same principles apply to loudspeaker arrays. When multiple antennas are used, either they are located in very close proximity to create a desired radiation pattern (such as the log periodic dipole often used with wireless mics) or they are spread out with minimum overlap to cover a large area (such as cell phone towers).
Loudspeaker arrays are like the first example. This seems easy until you consider that the ideal loudspeaker array must have the same radiation pattern for over 8 octaves, not at a single frequency.