Traditional PA vs Line Array: what’s best for you?Mark Ellis
All public address (although, let’s stick with ‘PA’) systems feature a few things in common. They consist of speakers, amplifiers, a mixer and some form of input. But beyond these commonalities, they come in many different shapes, sizes and configurations.
This often makes the choice of PA a tricky one for the sound engineer or venue. It isn’t always as simple as ‘big room = big PA’. Beyond output, all manner of things need to be considered; the type of audio content to be reproduced, the audience, budget, space restrictions and – let’s be honest – the willingness (or otherwise) of everyone to hump around incredibly heavy kit.
In this post, we thought we’d take a look at the traditional PA and compare it to the line array. Both do the exact same job (provide sound reinforcement), but in very different ways.
If you’re scratching your head over what’s best for your particular situation, here’s the only low-down you need:
Traditional PAs (‘point source’)
A point source PA consists of either one speaker or several spaced far apart. They broadcast the full audio spectrum and do so from a single point. The speakers themselves usually have a limited range, because they radiate sound in a spherical pattern, thus making it tricky to reach every corner of the room.
Point source systems are most commonly found at smaller gigs, be they weddings, pub music nights or dinner and dance parties. They’re what most sound engineers and bands rely on week-in, week-out and are usually the first experience anyone who gets into live audio has of a PA.
They’re instantly recognisable even to Joe Public, but so too are line arrays (more so than you may think).
Those towering speaker columns at big live music events like Glastonbury are recognisable to most people. We all like a big gig or two and, they’re always intrinsically present (although, admittedly, few people in the audience will take as much notice as us audio bods).
Line array PA systems feature a number of identical loudspeakers, arranged vertically in a line (hence the name) and are usually suspended from the ceiling or by crane.
Without going into the technical specifics (we’d love to keep you awake while reading this post), line array speakers pull off a neat trick by allowing the sound waves emitted from each speaker to interfere with one another. This enables them to project sound much further than point source PAs and in a controlled, directional pattern.
This is why line arrays are the default choice for big indoor our outdoor gigs – they provide a sound field that is completely unrivalled and which gives near perfect audio coverage for everyone in attendance.
When should you go traditional?
If the gig is particularly small, or if the audience is clustered close to the stage, a traditional PA is usually the best choice.
There are some practicalities to bear in mind, too. Line arrays don’t perform well when mounted on the floor, therefore if there simply isn’t the space, inclination or budget to go for that kind of system, a traditional point source PA is often far more convenient.
What about a line array – when does that make sense?
If you’re running sound at a big event or within a venue that is geared towards supporting large PAs, the line array should be your default choice.
There’s nothing quite like the frequency response or coverage offered by a line array system, and if the budget allows, it’s a solid choice for a whole range of applications.