Center Of Attention
A staple of Scovill’s designs for years has been a center loudspeaker array, accomplished on this tour with a column of six flown Anya modules.
The left-center-right (LCR) array approach came about in the late 90s, when the line array system he was using at the time couldn’t deliver primary coverage to portions of seating on the far sides, particularly a problem in wide venues like sheds.
“The choices were to fly smaller format boxes on the side to try to get energy there, or heaven forbid, try to hang another long line source that’s not terribly displaced from the main array, which would create all kinds of interaction problems that would happen, at least too much for my taste,” he notes.
His solution was to turn the main arrays outward about 10 to 15 degrees, and add an array in the center to enhance the horizontal coverage there, which would make the displacement distance within the bounds of what he wanted to achieve. It also improves the overall low-frequency phase of the PA by eliminating the need for displaced side arrays trying to cover small sections of seats.
“Another advantage to this design is that people who are off-center of the room don’t get into that weird thing where they’re looking at someone sing on stage and hearing the sound of the voice coming from a completely different direction,” he adds. “One of the things I really love about that center array is that it keeps attention focused on the center of the stage for the things that should be there, yet you can still do stereo and place instruments out in the stereo field where they should be. It’s the best of both worlds.”
One challenge to LCR designs is that there’s currently not a console available to do the divergence correctly if the engineer subscribes to using audio sub groups, which are often deployed in digital consoles to assist in getting input resolution signal correct as well as to facilitate things like parallel compression.
So it takes some compromise to develop a panning scenario where if something is panned center, it is presented at equal energy goes to all three arrays—left, center and right. This must be maintained due to propagation differences between any two arrays.
Another challenge is that with traditional line sources, it takes a long line to attain sufficient control, but an extended center array isn’t desirable, to say the least, for aesthetic reasons and sonic reasons. Output from all three arrays needs to be in phase (time coherent) throughout the projected coverage area, and without interfering with front fill.
Further, a really long center line source with the goal of improved low-frequency control results in poor coherence at the far center of the room. If you’re on-axis with the center array where the left, right and center are all converging, the result can be poor phase response in the vocal range. So it’s a balancing of trade-offs to get it acceptable for the target listeners.
“Anya helps overcome this challenge because you have so much control over the directivity that it doesn’t matter how many of them you fly,” he says. “You can tell the system (via the software), ‘I want you to start coverage 15 feet from the barricade, and to go just past the mix position, and then I don’t want any more audio up in the bowl from that center array.’
“And it does exactly that. It’s breathtaking how well it can be done, to have so much control. It makes for a very strong center image on the floor, and further, it’s really fun to mix because you get really impactful drums and bass guitar, all of those things sound really good. It really helps out with the low-mids overall.”