Addressing a large gathering requires a system that amplifies sound so that it reaches people away from the stage and they can listen comfortably. The systems are generally called as public address systems or P.A. system. This system can be used for human voice, musical instrument or any acoustic sound source or recoded sound or music.
A P.A. system that is generally used in public venues comprise of microphones, amplifiers, loudspeakers and related equipment. In recent times, mostly wireless microphone is used, as it gives the user to move anywhere on the stage.
The functions of different components of the P.A. system are
Microphone: This device converts sound to an electrical signal. Generally, two to three microphones can be connected to one additional input for tape is provided.
Mixer: This stage is used to isolate different channels from each other, before they are fed to the amplifier. The voltage amplifier is used to amplify the mixture output further. The processing circuit block consists of master gain control and tone control circuits.
Driver and power amplifier: The driver amplifier drives the amplifier to give more power. It is generally used as voltage amplifier that gives desired power amplification to its input signal.
Typical applications of public address system include sports stadium, public transportation vehicles and facilities, live or recorded music venues and events. Simple systems can be used in venues like schools, auditoriums, churches, and small bars.
The P.A. system has developed since its first use for commercial purposes. The few requirements of the system to work effectively are
Proper speaker orientation
Good quality microphones and speakers
Loud speaker impedances should be matched properly
Use of closed ring connection for loud speakers
Following the few tips, the public address system can be used at all desired places so that the message or music reaches number of people.
Source:https://portable-sound-system.blogspot.com/2020/01/3-crucial-parts-of-public-address-systems.html