Nearly all audio enthusiasts have heard of PA systems, but many are confused as to what a PA system actually is, how to set up a PA system and if they even need a PA system.
A PA system is an audio system that amplifies sound. It is used in a variety of settings, including live music venues, conference rooms, and educational facilities. A PA system typically comprises several components, including speakers, amplifiers, and a mixer.
PA stands for “public address” as the primary function of a PA system is to amplify sound to the public, or to “address” the public, so to speak.
In this article, I will dive deeper into the world of PA systems, explaining what they are and why you might need one.
I will cover:
- What does a PA system do?
- What are the parts of a PA system?
- What is the difference between a PA system and an amplifier?
- How many types of PA systems are there?
- Can a PA system play music?
- How to set up a PA system
- Do I need a PA system?
What Does A PA System Do?
A PA system allows people to hear speech and music clearly.
In a live music setting, for example, a PA system allows the audience to hear the performer(s) on stage.
In a conference room, a PA system can be used to amplify the presenter’s voice so that everyone in the room can hear.
If you attend a local gym class, your gym instructor may use an amplification system to shout instructions and play music; this is also an example of a PA system.
In a nutshell, a PA system amplifies sound, be it speech or music.
Because of the wide variety of applications of a PA system, they can come in many shapes and sizes.
For example, a PA system for a small conference room will not have the same demands and requirements as a PA system for a large music venue.
As a result, you can purchase (or rent) PA systems that are portable for a simple conference or large and heavy with multiple parts for a full touring band.
What Are The Parts Of A PA System?
There are several individual parts that make up a typical PA system. These parts include microphones, mixers, amplifiers, speakers, and cabling. Each part plays an important role in how the system works.
PA systems in general have the same components, with more speakers and components being added depending on the application.
For example, a small conference room with one presenter will require just two speakers, an amplifier and a microphone. However, a PA system for a live band will require multiple speakers, a mixing desk with multiple inputs, multiple microphones, and on-stage monitors so that the musicians can hear themselves.
Here are the main parts of a PA system:
1. Microphones
Microphones are used to capture sound waves and convert them into electrical signals.
2. Mixers
Mixers take the electrical signals from the microphones and combine them together. They also adjust the level of each signal so that they are all equalised.
This is important when using PA for a band. For example, you will want to adjust the volume level of the mixer to ensure that the drums, guitars and vocalists can all be heard well without one particular instrument being too loud or too low.
3. Amplifiers
Amplifiers increase the strength of the signal so that it can be sent to the speakers. Whether you need an amplifier will depend on the type of speaker.
Some PA systems use active speakers. This means that the amplifier is built into the speaker itself and therefore it does not require an external amplifier.
Some PA systems use passive speakers. This means that the speakers need an external amplifier to ensure that the signal is strong enough to be amplified.
4. Speaker
Speakers convert the electrical signal back into sound waves so people can hear them.
5. Cabling
Cabling connects all the different parts of the system together so that they can work as one unit.
From my experience, getting good quality cabling with strong connections is a great investment, as good quality cabling will last longer and give a better overall quality of sound.
The above components are the main parts common to nearly all PA systems with some variation when it comes to amplifiers and mixers.
If you are using PA for a large venue or live band, you may need some additional components, such as:
6. Monitors
On-stage monitors may be needed so that the band members can hear themselves.
As we always place PA speakers in front of the microphone to reduce the risk of feedback, band members cannot hear themselves clearly or even their other band members. On-stage monitors which face the band and not the audience can help with this.
7. DI Boxes
With all the long cabling needed on stage for a large band, we may need a DI box for guitar signals to boost the signal without adding any external noise into your mixer.
What Is The Difference Between A PA System And An Amplifier?
In general terms, a PA system refers to the entire system to amplify sound, including the microphone, amplifier, mixer, and speakers.
An amplifier, on the other hand, just refers to the amplification stage. The part in the signal chain that amplifies sound.
In terms of a guitar amplifier versus a PA, a guitar amplifier has a much narrower frequency range than a PA system.
As a PA system can amplify the entire frequency range, from bass to high-pitch voices and instruments, a PA system is the better option for amplifying a wide frequency range.
Guitar amplifiers, on the other hand, are designed for guitar. They can work with other frequencies outside of the guitar frequency spectrum, however, lower bass frequencies can damage guitar speakers and high-end frequencies such as vocals can sound dull.
How Many Types Of PA Systems Are There?
PA systems come in all shapes and sizes, from small portable systems to large-scale distributed systems.
In general, you could say that there are three types of PA systems; small systems for one performer, medium for a small band with multiple mics and large or “full-size” for large venues, with multiple microphones and speakers.
The speaker types within a PA system can generally be classified into three types; “mains” which cover most of the audio frequency range, “bass” for lower frequency amplifications, and “monitors” used to allow the speaker or musician to hear themselves.
The technical specifications of a PA system will vary depending on the size and purpose of the system. Some things to consider when choosing a PA system include the power output of the amplifier, the number of channels on the mixer, and the type and number of speakers.
Can A PA System Play Music?
PA systems have a reputation for being for spoken word only. This makes sense, as the PA system started life as a broadcaster of voice back in the early 1900s.
PA systems are good for playing music. Like all speakers for playing music, there will be some variation in how music sounds on a PA system.
Many PA systems will have a mixer or in-built EQ within the speaker, which you can adjust to modify the sound you are hearing. For example, if the bass is too muddy or the high-frequency sounds too harsh, you can use EQ functionality to get balance in the music and create great sound music.
Even cheaper PA systems today are great at playing music. As mentioned, there will be a few that don’t sound wonderful, but overall PA speakers are designed to accommodate the full audio spectrum so can reproduce music well.
Of course, if you are a very critical listener, then don’t buy a PA system for your sitting room! Stick to high-quality stereo systems designed for high audio reproduction.
For general venue amplification, PA systems can play music well.
How To Set Up A PA System
There are some fundamental rules to follow when setting up a PA system. These rules are essential to follow to ensure that your audio sounds great without noise.
1. Speakers In Front Of Microphone
The first golden rule of PA system setup is to ensure that the PA speakers are in front of the microphone. This is essential to follow.
If the microphone is faced towards the speakers, it will create feedback, which will cause a strong and painful noise. Feedback is very unpleasant to hear.
2. Never Point The Mic To The Speakers
Ensure that your presenter or vocalist does not point the microphone towards or into the speakers. This will create feedback.
3. Speaker Spacing
Try to position your speakers in a position where there is sufficient space between your speakers. Don’t place your speakers too close together.
This will distribute the sound throughout the room and get the most volume and sound coverage from your system.
Do I Need A PA System?
There are many reasons you might need a PA system.
If you are hosting an event where there will be multiple people speaking, you will need a PA system so that everyone can be heard loud and clear.
If you are a musician who is playing at a small venue, you may need a PA system to amplify your sound.
Any situation where you need to be heard by a medium to large audience requires a PA system.
It is possible to rent PA systems, therefore; it is a great idea to rent a PA system before you purchase or invest to get an idea of how they work and what you really need for your sound needs.
Final Thoughts
A PA system is an audio amplification system that is used in a variety of settings, such as live music venues and conference rooms.
A typical PA system comprises several components, including microphones, mixers, amplifiers, speakers, and cabling.
The technical specifications of a PA system will vary depending on the size and purpose of the system.
The best way to learn about a PA system is to get some hands-on experience. You can speak to local venues to see how their systems work or even volunteer at live gigs or events to get some real-world hands-on experience with a PA system.
Happy listening!
