Do I Need a Line Array for my Event / Venue?
When line arrays started becoming more available a couple of decades ago, it seemed like everyone wanted one. No one really understood how they work, but we all thought it was the latest, greatest technology, so they became very popular. They sounded good and they made touring easier because they could adapt to lots of different seating configurations. But are they appropriate for all venues?
A little line array theory will help with that question:
What are line arrays good for? Combining drivers in an array produces some highly beneficial results:
Large transducers (speaker drivers/cones) in close proximity work together to produce more volume and lower frequencies. A bass cabinet with 4 10” drivers has more surface area than a single 18” driver. The less mass of the 10” cones allows them to efficiently produce all the higher frequencies an 18” cone can’t produce (because it can’t move as quickly as the 10”), but by working together, they can also efficiently produce lower frequencies than the 18” can because of the increased amount of surface area.
2. Putting transducers close together better controls the directionality of frequencies. More boxes hanging equates to a bigger waveguide, directing longer wavelengths (lower frequencies). That allows us to keep more of the lower frequencies off the walls (and the stage) and “focus” them into the house. That also makes them go further.
3. Shaping the speaker boxes into a J gives us very good control of the sound levels front to back by allowing us to focus sound further (with the flat front) to reach the back of the room, and spread it out more for the closer seats.
Because line arrays require multiple boxes to do what they do, every good speaker manufacturer will tell you that you have to have at least 4 cells (individual line array boxes) together to get any benefit, but anything less than 6 is not doing much. In fact, if you try to buy a system from some manufacturers, they will not sell you less than 6 boxes per hang. At $8k and up for a single cell, that adds up fast!
When we design sound systems for venues, we look at throw distance (how far is the back row from the speaker), width of the seating area and how high we can get the speakers.
A typical point source (1-2 speakers) can throw a maximum of about 50’ before significant deterioration in the quality of the sound. Longer throws will require delay speakers or an array to cover the area. If the room is wide or the stage projects into the room with seating on the sides, a line array gets very expensive because of the more than 180° coverage required. Many line arrays only cover 90° in the horizontal, which means 4 or more hangs are required. Remember that you need 6 boxes of line array per hang! Unless the throws are more than 50’, a line array is the wrong tool for the job.
Height is also a determining factor. While some line arrays can be stacked on the stage, the preference is to hang them–just like with point sources. It’s pretty difficult to get the required J shape with 6+ cells ground stacked. The front row still gets blasted and the idea of even coverage front to back is completely lost. Where ground stacking works is when there’s a significant rise in seating from the lip of the stage. The top cabinets can be angled to push to the back row, which takes advantage of the line array capabilities, but the front row still gets hit hard. If your ceiling is low, a line array can also dwarf the stage or hang down far enough to interfere with sight lines.
Line arrays are a great fit for touring where the show is in a different venue every night. They adapt quickly to a variety of seating configurations and can throw sound far enough to reach the upper seating of an arena bowl. They’re also a great choice for an installed system where a long throw distance is required.
If your venue is wide, or the throw is 50’ or less, there are plenty of point source options that can fill the space with sound and reach the levels you want to hit, without breaking the bank.
