What Is A PA System? 1
by Aether in
Audio Tech

Last Updated on November 4, 2019 by Aether

We’ve no doubt all been in noisy environments when raising our voices to screaming level, we’ve shouted ‘I need a microphone just to make myself heard!’.  

A PA or Public Address system is able to amplify the sound of just one voice or an entire orchestra. The system projects quality sound so that everyone in the room or even outside can hear.  

If you want to use your system for a variety of different events and venues, look for a flexible something that allows for many inputs as well as more complex onboard mixing. Now let’s dive in and take a look at what makes a PA system that you can rely on.

Variables to consider 

There are many applications for a PA system, and they are made up of quite a few parts which can all be integrated together. You’ll become familiar with the likes of speakers, adapters, power cables, XLR cables, mic stands, RCA, microphones and more. PA systems come from top brands such as Peavey, Fender, Yamaha, Behringer, JBL and lots more.  

There are a host of variables to take into account when looking to invest in such a system, and the casual guitarist in a pub will want a light, portable system, while a much bigger venue will have to look at far more wattage.  A medium-sized venue will require about 1500 watts of power while a smaller venue can get away with 750 watts or even less.

The sound each venue wants their audience to hear will be captured by a microphone and processed by a mixer before being amplified. A PA system will only need a power amplifier with passive speakers. Active- or powered speakers have a built-in amplifier, allowing you to connect it to a mixing board.

PA systems are made up of some basic components


You’ll find many different sizes and types – mains, subwoofers and stage monitors each with their own functions. For instance, the main speakers form the bulk of the PA’s sound.  Subwoofers are bigger than the main speakers producing lower frequency than the mains. 

To separate the sound of the subwoofers and mains, a crossover unit is used, sending lower frequencies to the subwoofer and higher ones to the mains.  


There are plenty of microphones on the market for amplifying your voice, with the most common design being the dynamic microphone – the handheld microphone and the lapel microphone. The microphone converts soundwaves into an electrical signal. 


Commonly referred to as an amp, this component electronically increases the level of the sound source. You get built-in amps known as powered mixers, but if you have a separate amp, cables will be required to transmit the signal from the mixer to the amp. 


Loudspeakers churn out a whole lot of sounds and mixers simply allow different sound sources to be blended together, whether analog-, powered analog or digital. Analog mixers have less audio effects than digital mixers.

Depending on your venue and event, these mixers can be single input designs to huge mixing consoles and desks. A microphone isn’t required when sound sources such as laptops or MP3 players are plugged into the inputs.

Cables and Inputs

Different cabling, all long enough,  will be needed to connect the components of a PA system and transmit audio signal. Have you got enough inputs for everything you’re plugging in, bearing in mind there are different connections for iPods and laptops.

All-in-One models are convenient and powerful

All-in-one or portable speakers are super. They can be a simple way to get set-up, and a tower system will house a mixer, power amp and speakers. Of course, just sometimes you might miss out on the range of sounds which come from separate audio components.

Look at the JBL EON ONE, for instance, a system that simply folds up niftily into the subwoofer, making it easy to transport. It comes with a 10” subwoofer and the sound is exceptional. The system has Bluetooth pairing so you can stream straight from your smart device.

What makes a good PA system

How much power do you need? Power is produced by the amp and measured in watts. A good system will have the right wattage so that you don’t end ud up with a distorted sound. 

The best systems come with heaps of options and configurations. One that projects quality sound so that everyone in the front rows and at the back can all hear equally well. 

 A huge open-air musical festival such as Woodstock, held on a 600-acre dairy farm and with some 500,000 noisy hippy rockers won’t have the same requirements as the village church with 30 attendees. On the other hand, if you’re going to hit the streets busking, you’ll want a lightweight, portable, battery operated amp such as The Roland Cube Street.

There are both non-battery- or battery-operated options available to consumers. If you need to use your system outdoors which power sockets aren’t available, a battery-operated option would be a wise choice.

PA system specifications to look for

Not everyone is high-tech and can even begin to comprehend all those spec numbers and symbols, but one or two important things to look out for include:


This is measured in decibels or dB. A speaker’s sensitivity is indicative of the loudness of the speaker. All speakers have a listed sensitivity rating. This measures how a speaker converts wattage into SPL. As a guide, a regular speaker comes with a sensitivity of about 88 dB but one with a rating of more than 90 dB is looked upon as being very good. 

Frequency Response

This is measured in Hertz (Hz) and is an indication of how low and high a speaker can play. The lower the number, the deeper the bass, whereas 20,000 Hz represents the highest treble possible. A speaker that reaches 50 Hz or lower is considered good and won’t require the assistance of a subwoofer. 


This is the speakers’ resistance to power, Most loudspeakers are rated at an impedance of 8 ohms. Most high-end amps and speakers are rated at  4 to 6 ohms. Together with good Sensitivity Ratings, you get an efficient loudspeaker.

Summing up

There are a number of things that come into play when choosing the right option for you. The microphone, the amplifier, and the speakers all need careful consideration. Take time to do proper research and you should be able to find a PA system that fits your needs.

Aether has been playing World of Warcraft since 2006. In his youth he raided 7 days a week, but now just plays with friends doing Mythic dungeons and Arena. He swaps his main more often than he should.
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