Beginner’s Guide To PA Systems

Mackie Thump

Stuck understanding PA systems? Need to rent or buy one for your shows? Scared about plugging into or playing on a PA? Want to know why you need one at all, when you could take your home stereo speakers to the party and use those instead? If so, trust me – you’re not alone. This guide is here to help. I’ve helped lots of DJs like you, as well as many live acts, with getting the best from PA systems, and I’ve been doing it for a long time – even longer than the 15 years I’ve been DJing. In that time I have used lots of different PA systems, in places from small wedding venues right up to festivals with tens of thousands of people.

Furthermore, in my role as moderator of the Digital DJ Tips forum, I know full well how many DJs know very little about this important subject, judging by the number of questions asked about PAs. Which is why we decided it’s high time to start unravelling some of the mysteries of PA systems from the point of view of DJs.

Just a word: What I’m offering here are views based on my own experience over that time. While I have not studied theoretical physics to prove what I believe, I have seen and heard enough to be pretty sure these guidelines are right. So experts might think differently about some of the minutae of what’s here, and who knows, on some points they might be right – but on the other hand I can’t remember a time that things haven’t work out well for me with PA systems, and I get a lot of compliments for my great sound. So having made that clear let’s go!

What this series does and doesn’t cover

Line array
Looking for the low-down on this type of PA ( a ‘line array’ system)? Sorry, we’re not going there…

This is a big subject, so let’s narrow down what we’re going to look at. This guide discusses low to mid-range PA systems, because these are the types of system that reader of this website are going to want to buy and are most likely to find themselves using. So I will not touch line array systems, for instance, as that is a whole different world and frankly if you’re DJing on that scale there will be audio engineers about to help anyway. (And if you do not know what a line array is, do not worry about it.) Also I am not touching big club gear in this guide. Big clubs present a very different environment to “simple venues”. The basics still apply, but you have to consider more things. Possibly we’ll cover these in a later guide or course.

Finally, I also get a lot of questions regarding “new stuff” like PA mixers that you can configure with iPads, active speakers that look like trumpets and so on. While we can’t cover all of this in a basic guide, the basics do apply in my experience. What’s more, if you familiarise yourself with these basics, you can more easy decide what is real innovation and what might in your case turn out to be only “for show”…

What is a PA? Why is it different from hi-fi system?

PA means “public address” and basically a PA is a system that is meant to provide a public (audience) with a constant quality of sound for a long period of time. Hence a PA system has some qualities that are different from common hi-fi-type equipment. We will cover the differences as we work through the guide.

Usually a PA system consists of three parts: A sound source (for DJs this is your sound card or controller “line” output), an amplification system, and a speaker system. But before we look more closely at each component of a PA system, let’s think first what we actually need from a PA system, as the needs of most DJs are different from a band or vocal presenter, and these needs will determine how our DJ PA is put together. It’s time to look at some basic set-ups.

The most common DJ PA set-ups

1. The basic DJ set-up

So here’s a simple, basic set-up. (Note that in all these block diagrams, the sound travels from source [left] to output [right]. Also you can substitute “DJ controller” for “DJ mixer”, “DJ audio interface” etc – basically, it’s the master output from your DJ system.)

Basic PA set-up.
Basic DJ set-up.

This is the most basic set-up. Indeed, if you decide on active speakers (speakers with the amplifiers already built in) it can get even down to DJ controller and speakers! However the blocks are still there, it is just the routing with cables from the amplifier to your speakers has already been done for you by the manufacturer in the one cabinet.

2. The “enhanced” DJ set-up

Enhanced PA set-up
Enhanced DJ set-up.

The PA mixer is really no different to a DJ mixer in what it does (mix sound sources). Indeed, one might think that a PA mixer is not actually needed if you only use your controller. However, there is one big advantage to using a very small PA mixer, even in such a case: You can set up your DJ controller totally flat (ie all EQs are to middle and the master output is to 50%) and then do the sound check (see later in the series) from the PA mixer.

This way, you can still perform easily on your DJ controller and if you do not touch the PA mixer after the soundcheck everything should stay OK and sound will be good. That is why I recommend this set-up as enhanced over the above one.

3. The mobile DJ set-up

Mobile DJ set-up.
Mobile DJ set-up.

Again, in this set-up you can substitute the sound sources for other things; the microphone could be wireless, the iPod could be an iPad and of course it could also be a spare CD player or whatever… but the idea is the same. The point is that the PA mixer is the hub to joins all the connections from sound sources.

Now some DJ controllers do have microphone inputs, but most DJs prefer this kind of set-up as the talkover function on DJ controllers (the thing that ducks the music volume when the mic is in use) is in most cases not as good (if it exists at all) in a DJ controller, and a PA mixer will usually give you a greater level of control.

(Note that in established venues with DJ booths, often a pro DJ mixer either takes the place of the PA mixer here, feeding straight to the PA amps, or comes before the PA mixer, feeding into it, in which case the PA mixer is where you’ll typically find the dedicated venue sound engineer lurking…)

However, there are times when you may be forced to use the microphone input on your DJ controller, which is when you might encounter…

4. The “mini mobile set-up”

Mini mobile set-up
Mini mobile set-up.

I know some mobile DJs who use this set-up instead. These DJs tend to be new and don’t yet have the money to buy a PA mixer (even though such mixers relatively cheap, as we’ll find out). Indeed, some DJ controllers even have another Aux in, where you can connect an iPod or CD player. The better your DJ controller, the more likely such a set-up is to deliver good results for you.

Next time…

So these are the very basic set-ups. I hope you can see that it is very simple if you think in these building blocks, there is no magic or voodoo about it. Nothing to be afraid of.

Where it all gets a bit more technical is in choosing a PA system, as there are lots of factors involved in choosing correctly. So in the next part we answer some common PA questions to help get you set..

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