If you read my article on how to organise a gig and you are planning an event that requires public speaking or music then the chances are that you will need a PA system. There are plenty of places that rent these out and even provide a sound man (an engineer who operates the equipment). This is a good thing but what if you rely on being heard often? The rental fees will soon add up and for the price you pay you can probably pick up the components to build your own PA system. Obviously there are times when it is best left to professionals but if you are willing to learn new skills then there are clearly benefits to owning your own system.
My PA system Outdoors
There are three major components for a very basic PA system and these are the speakers, the amplifier and the microphone. A mixing desk or microphone preamp is often used so that the signal can be adjusted and multiple microphones may be used. A device that combines the mixer and the amplifier is available and is sometimes called a power pod. These are excellent for someone who does not have very much expertise in PA systems because all of the connections are made inside the box without need for cables and sockets, meaning that only the speakers need to be connected.
The choice of speaker is very important because they are the source of the PA sound. Using the different types of speaker incorrectly can lead to equipment damage. The three basic types are active, powered and passive speakers. Passive speakers should be used with a power pod or amplifier whereas the active type can work with the unamplified signal from the mixer but require their own power supply. Some powered speakers still require an amplified signal to work even if they require power. Active and powered speakers provide better sound quality than passive speakers (usually) but they are more expensive. Whichever type is best for you will depend on your requirements for sound quality but remember to make sure that whatever type you choose you get the correct amplification/mixing equipment.
You will need cables to connect your equipment and there are many places online and on the high street where they are available. Do not confuse speaker cable with signal cable such as that from a microphone. Speaker cable may have the same connectors as other cables but it is unshielded. that means that it is likely to pick up noises from electrical appliances and power lines. Use shielded cables to connect audio sources such as music from a guitar amplifier or a microphone.
Out of the Box Solutions
For those who only want a simple solution many companies are now producing a portable PA system kit containing everything you need at a one off price. These are actually really useful as they are designed to be as powerful as they can and still be small enough to fit in the boot of an average car. While these wont be suitable for a rock band they are great for use at small events like children's parties or church fetes.
Think About Your Surroundings
You need to think about the size of the venue where you will be using the PA system in order to make the most of it. A large hall and a small room will obviously have different sound qualities and this will provide you with different requirements. A room with a lot of echo will need more speakers along its length to generate the sound at a steady rate throughout the room. A small room will only require a minimal number of speakers as the sound will not have far to go. Due to the modular nature of PA equipment if you have a large system you do not need to use all of it at once, this is good if your situation varies.
How To Use The Equipment
The operation of the PA system may seem daunting but there are some simple rules that will enable you to get a decent sound without having to be an expert. I will start by giving some general guidelines on setting up. Before you switch anything on turn all of the gain knobs and faders to their lowest setting. This is known as zeroing the board with the mixer but you should do it to the amplifier too. Set up your speakers in the position you want them to be. They should be facing the audience that you want to hear the sound. next find a suitable place to to put the mixer and amp, I prefer a table so that I can sit at a chair while fiddling with settings on the mixer. Once the major parts are in place connect them together with the correct cables. The instruction manuals that come with your mixer and amp will show you how to do this. The most important thing is never to feed a fully amplified signal into your mixer or you will do great (expensive) damage. Switch the amplifier on then switch the mixer on. Increase the volume on the amp to the highest level so that when you send a signal to the speakers they are fully driven. Increase the master volume on the mixer to "0db" which is usually clearly marked. Finally you can turn up your channels and you should be able to hear sounds through the speakers. If you are using a microphone you will need to make sure that it is not in front of the speakers, if this happens it may pick up its own signal and send it back to the speakers which is an effect called feedback. Feedback sounds horrible so make sure the microphone is in line with or behind the speakers. Usually there are lights on the mixer or amp that indicate when there is a signal happening. If they are going all the way to the top you need to turn down your input signal because the sound is being distorted and worse your gear is taking damage, this is called clipping and your manual will probably have something about it, so read it, it is important.
I have recently started a series on how to use a mixing console which you should read if you are serious about learning how to use a PA system.
Well I hope that has inspired you and even helped. Why not check out my articles on how to use your computer to record so you can record the soundtrack of your event.