There are many different types of public address system available on the market for various requirements. The term PA or public address means different things to different people, for example a PA rig is a common term for a high power amplification system used for performances by artists and bands. Public address and sound reinforcement are terms used for amplification systems used for other purposes.
A Brief History of Public Address
From earliest history, man has felt the need to communicate with others, both singly and in groups. It has been group communication however, that has presented the difficulties as it has been limited by the limited number of people that can be conveniently assembled within earshot of the speaker.
Whenever a very large crowd had to be addressed in earlier times, the only way to do it was with relay speakers, who stood within earshot of the speaker and repeated what he had said at suitable intervals. Others within hearing distance transmitted the speech even further until it reached the edge of the crowd. These speakers were usually arranged in concentric circles, with the original speaker at the centre. There were frequent pauses and delays, and errors would be passed on and added to.
Public Address Today
Today amplification systems enable buildings and gatherings of all sizes to be addressed with ease under varied circumstances. There is increasing demand for such facilities, from small venues to large sports stadia, from meeting rooms to conference centres, from schools to universities and from small businesses to large industrial plants.
The main requirements of any public address or PA system where speech is being amplified are that the programme material must be heard comfortably by all the audience or public present, and that the speech is easily intelligible. Naturalness is a desired quality and in instances where speech reinforcement is required, if everyone present can hear clearly without being aware that amplification is in use then the installation can be claimed as successful.
It may not always be possible to achieve complete success in this direction especially in large gatherings; however the system should be as unobtrusive as possible but always second to providing intelligible reproduction.
It may be worth discussing the difference between public address and sound reinforcement systems. The terms are somewhat self-explanatory, sound reinforcement is used to enhance the natural voices of speakers where they would otherwise be insufficient to reach the whole audience. Examples of this type of system would include a church or place of worship and a lecture theatre.
Public address however is where the public is to be addressed, in other words the audience is large and spread over a wide area, which prevents being reached with the natural voice. Often the speaker will be remote from the listener as in the case of a station announcer or factory public address system.
This website aims to be an online source of and audio related and technical information for those involved with or interested in, commercial and industrial public address systems.