PA systems are suitable for high-quality sound reinforcement of concert halls, large event halls and stadiums. The "PA" stands for Public Address, which refers to the use in public areas. The German term for a public address system is Beschallungsanlage.
In sophisticated PA systems, clusters of loudspeakers are used for sound reinforcement, wherever the reproduction quality of speech and music must meet the highest requirements. PA sound reinforcement systems consist of acoustic power systems with audio players, equalizers and effects units, mixing consoles and power amplifiers, PA loudspeakers, midrange speakers and subwoofers. The number of speakers in such PA sound reinforcement system is practically unlimited, so speaker arrays and clusters can consist of 50 or more speakers. Such PA speaker arrays and PA sound reinforcement systems may well have several thousand watts of power.
If loudspeakers are arranged at a greater distance from each other, then when all loudspeakers radiate the same signal, this leads to disturbing time delays due to the speed of sound. To compensate for this disturbing effect, the signal for the dielectric sound is reproduced with a time delay in the distant loudspeakers. In this context, one also speaks of delay stacks. This compensates for the time differences and creates a natural listening impression.