What Not to Do
In this example, loudspeakers are installed at each corner of the facility pointing towards the center. Note that the distance from each loudspeaker to a listener is different; so, the time it takes for sound to reach the listener from each speaker is different. Result: the listener will hear the audio echoed four times. While the echo times are short, they still HUGELY reduce speech clarity. Not good.
The Correct Approach
In this example, all four loudspeakers are installed at in the center of the facility in a cluster. The four loudspeakers act as one large, system, covering the whole base. No matter where a listener stands, he or she hears the cluster a single, unified source of sound. This means that the sound from the cluster arrives at one time, and there is no speaker-location created echo. Speech and music is clear and highly intelligible.
Note: if a base area is VERY large (multiple square miles), you will have to use multiple PA systems to cover it. However, the overall goal remains the same – in any given area, listeners should hear only ONE source of audio. Technomad PA systems allow you to adjust their coverage pattern, so you can keep one PA from “spilling over” into another PA system’s coverage area.
Many military “siren-oriented” PA systems only offer fixed, 360-degree coverage, so you cannot prevent adjacent PA systems from interfering with each other.