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Merging Science & Art: Can Anyone Catch Up With Systems Engineer Liam Halpin?

Case studies on fully utilizing new technology as an early adopter, even before there’s anything to adopt.

While out with Sam Smith last year, Halpin served as systems engineer, a role he’s a natural for and one he feels that there’s a shortage of people for.

“Among the new people coming up in live sound today,” he said, “everyone wants to mix. This shouldn’t come as a surprise, as historically there’s always been a lot of emphasis on mixing in our industry. Going to work at front of house is a high-profile proposition, both in front of the public and the crew.

“The role of system engineers has been cast into the shadows to some degree as a result, a fact compounded by the advent of powerful front-end and design software, which has led many to believe that basically anyone with a pulse can do the job. Such is hardly the case, however. You have to be aware of comb filtering between different sources, the alignment of countless different aspects of the system, so many things – the devil is in the details. It’s a field of study in its own right actually, maybe even an art.”

The homework translated to reality, resulting in more than 170 d&b audiotechnik enclosures in the air.

Halpin’s time thus far with Smith serves to illustrate this point. With Smith performing on a long, triangularly-shaped stage that placed him on a runway leading almost halfway out into the arenas along the tour, Halpin has frequently been heard describing the show’s audio blueprint as “in the round, but not the middle.”

“It wasn’t an in-the-round show, it wasn’t an end-stage, it was the ‘bastard stepchild’ of the two,” he quips. “We went out with 80 d&b audiotechnik J8 enclosures flown in four arrays of 20 cabinets each, 32 d&b V8s flown in arrays of 16 cabinets each, and 24 d&b J-SUBs flown in six arrays of four cabinets. A ground/fill system utilized four d&b J-INFRA subwoofers and four d&b V-SUBs in two stacks of two cabinets each.

“Due to the design of the stage and the presence of a ‘mine cart’ rail track used to transport Sam to a downstage lift position, there were limited options for placing the subs on the ground. It took extra effort and a fair amount of ingenuity to deal with that reality and still obtain a level of coverage across the house that was consistent at every seat.”

Serious Homework

Halpin’s approach to dealing with the show’s inherent lack of proper space for the subwoofers on the ground was to use delay times and calculations based upon modeling done in four dimensions, actual measurements, and venue-supplied CAD drawings to engineer a distributed arc that would mimic the characteristics of the type of array that would traditionally be placed across the front of a stage.

“However you want to describe this hybrid system,” he says, “you can’t deny the plain, simple fact that we needed a full 300 degrees of coverage. That’s easy enough to achieve in the top-end, but the low-end was a different story. I initially considered doing a circle of subs like you would use in an actual in-the-round design but found that I couldn’t project the kind of energy we needed to hit the balconies and rear blocks of seats. Building a virtual arc was really the only answer.”

A closer look at the flown array structure.
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