Public Address System or PA System Explained with Diagram


A public Address System or PA system is an electronic system that includes acoustic signal converting, mixing, amplifying, and playing. A PA system has microphones, amplifiers, and loudspeakers as its main components or equipment. We know that the intensity of the sound decreases with the distance. Also, a particular sound can be affected or distorted by the other sound if the level or volume of the sounds is the same. So, if we want to deliver the sound energy for a long-distance or highlight a particular sound or voice in a large crowd or gathering then we need a PA system. Because the PA systems provide the amplification of the sound for comfortable listening.

The range of amplification is required for the sound is to be delivered to the distance, size of the gathering or gathering, etc. Sound quality is also a very important factor with amplification because it improves the listening experience. The PA system helps to amplify as well as record the voice of any human being or the sound of any musical instrument. Also, it helps to communicate between a group.


Basic Block Diagram of PA System


Here, you can see the public address system block diagram and its important blocks.

Public Address System or PA System Block Diagram


Components of a PA System


There are so many devices or components are used in PA system that depends upon their applications and other factors. But the main three components of any public address system are explained below.

1. Microphone


The microphone is a very important part or component of a PA system. The microphone basically is a transducer that converts acoustic energy or sound energy into electrical energy. It continuously generates the pulsating electrical voltage according to the frequency of the sound energy applied to it. There various types of microphones are used in the PA system. The main basic two types of microphones are,
  1. Handheld Microphone
  2. Lapel Microphone
Other different types of microphones are,
  • Wired Microphone
  • Wireless Microphone
A wired microphone can be connected by a wire to the mixer or amplifier. It is very simple. But the wireless microphone needs a battery and the frequency of its signal is also a very important factor. The wireless microphone cannot be connected directly to the mixer or amplifier. A receiver is required that can receive the signals sent by the microphone. This receiver is to be connected to the amplifier.


2. Amplifier


The amplifier is the second part of a PA system. The main function of the amplifier is to amplify or increase the volume level of the audio signal that can drive a loudspeaker. The requirement or size of the amplifier depends upon the number and size of the loudspeaker. If the size of the loudspeaker is very large or so many loudspeakers are to be connected then a very powerful amplifier is required. The output of the amplifier is measured in watts or kilo-watt. 




3. LoudSpeaker


Loudspeaker provides a very important role in the PA system. It converts electrical energy into acoustic energy or sound energy. The loudspeakers are generally connected to the amplifier and it generates sound according to the audio signal provided by the amplifier. There are different types of loudspeakers are available according to their operating frequency.
  1. Woofer - it operates at the lowest frequency audio signal such as Bass
  2. Subwoofer - it also operates with low frequency but more than the woofer such as bass and deep vocals
  3. Squawker - it operates with medium-frequency audio signals such as vocals
  4. Tweeter - it operates with high-frequency audio signals such as tone




4. Mixer


A mixer is not a necessary part of a PA system. But if there are multiple audio sources or multiple microphones used in the PA system then a mixer is must required. The mixer is an electronic device that can control multiple sound sources simultaneously. It can mix all the sound sources together and play with a single loudspeaker with the help of an amplifier. So the mixer is generally connected before the amplifier. Nowadays, there are so many amplifiers are available in the market that already has an inbuilt mixer. So there is no need for an external additional mixer. All the microphones or sound sources can be connected directly to the amplifier.


PA System Wiring and Connection Diagram


Here, you can see a basic wiring diagram of public address system. This will help you understand how microphones, mixers, amplifiers, and speakers are connected together.

Public Address System or PA System Wiring and Connection Diagram


Here, you can see, the multiple audio or sound sources such as microphones and music players are connected to the mixer. Then the mixer output is connected to the amplifier input. And the amplifier output is connected to the speaker.



Important Factors in a Public Address System


Acoustic Feedback


When the microphone picks up sound from the speaker and re-amplifies and sent again to the speaker then it is called Acoustic feedback. The objective of any pa system should be to minimize as much as possible. It distorted the actual sound and make a bad experience of listening. It generally happens more when the volume of the system is turned up to the highest level.

This can be reduced by the different procedures,
  • by keeping microphones at a distance from the speaker
  • changing the direction of the microphone from the point towards the speaker
  • lowering the gain level of the feedback sound
  • using some devices like notch filter, graphic equalizer, parametric equalizer, etc

Cables and Wires


The size and quality of cables used in the PA system is a very important factor. Using the proper size and good quality cables and wire improves the sound quality very much.


Types of PA System


The PA system can be classified such as,
  • Personal PA System
  • Medium Size PA System
  • Large Size PA System
  • Portable PA System

Applications and Uses of PA System


1. PA system is used in group meetings, presentations, concerts, theaters, large halls, etc.

2. PA system also used in sports, stadiums, travel system, security system, conference system, etc.


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Public Address System or PA System Explained with Diagram Public Address System or PA System Explained with Diagram Reviewed by Author on 11/20/2021 Rating: 5
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