Going For Balance
To accommodate the tour’s exceptionally long, triangularly-shaped stage, which effectively places Smith on a runway leading almost halfway out into the arena at the far end, the PA blueprint was formulated in a fashion not terribly unlike how it would have been done in the round.
“Mixing is a different discipline on this particular system,” Ebdon imparts. “There’s no wide stereo sound anywhere. Nothing is panned wide. I’ve elected to mix off to one side in response. No traditional power alley exists for me or for any other member of the audience. Consequently it’s not a very loud show, but it is very well balanced, and accurate.”
The main portion of the system comprises 80 d&b audiotechnik J8 enclosures flown in four arrays of 20 cabinets each, 32 d&b V8s flown in arrays of 20 cabinets each, and 24 d&b J-SUBs flown in six arrays of four cabinets. A fill/ground system utilizes four d&b J-INFRA subwoofers and four d&b V-SUBs in two stacks of two cabinets each. The front fills, 22 d&b T10 boxes, are mounted directly to the stage structure with custom hardware.
All flown full-range cabinets are driven by d&b D80 amplifiers and array processed. The amp count is 63, excluding spares. Floor sub amps (D80s again) reside in a bay underneath stage right, upstage of the J-INFRA subs.
Every amp is connected to a dual, redundant Ethernet network using (Audinate) Dante-equipped d&b DS10 network bridges controlled via Open Control Architecture (OCA). A Lake processing rack at FOH accommodates signal distribution and house EQ.
Due to the design of the stage, there were limited options for placing subs on the ground, a factor further exacerbated by a “mine cart” rail track that facilitates Smith’s access to a downstage lift position.
“I was trying to replicate a distributed sub array like we would normally put across the front of the stage with this design,” explains systems engineer Liam Halpin, “and create a virtual arc with delay times. In order to do that, I had to calculate the sub positions based upon four dimensions that included actual physical locations as well as time delay settings. All of this done with the goal of optimizing smooth coverage and to provide as much flexibility as possible for low-end steering.”
The sub stacks and J8 hangs actually all act as part of the sub steering system. With all time alignment being performed with the aid of d&b ArrayCalc software and enhanced for the best average response across the whole audience, the results of the predictions are made as accurate as possible by working with a combination of venue-supplied CAD drawings and actual measurements taken on the day of each show. A task taking anywhere from three to 15 hours to complete, the process also insures the accuracy of the processing filters.
“Put the results of this effort all together, and we obtain a level of consistency that is as good as it can possibly be,” Halpin adds. “In turn, we provide Jim with a level playing field that lets him deliver his mix and system EQ decisions to the audience in a fashion that is equally relevant for everyone. In simpler terms, whatever Jim does with his mix will be heard the same way in every seat in the house.”
