A Traction Sound ‘Raptor’ 30-subwoofer bass-array was recently installed in the Turbine Hall of the Tate Modern in London to transmit the sonic element of a multi-sensory exhibit.

The commission, inspired by the global immigration crisis, is the brainchild of acclaimed Cuban artist and political activist Tania Bruguera, and aims to provoke a moving, emotional response from visitors.

Influential producer/DJ and founder of the Hyperdub label Steve Goodman (AKA Kode9) provides the soundtrack, which is designed to make visitors feel uncomfortable and intimidated, whilst touch and atmospheric elements evoke feelings of empathy.

Specified and installed by Brighton Sound System, Raptor is reproducing the demanding source material as the artist intended eight hours a day, every day for a five-month period. The bass array is driven by Traction Engine amplifiers based on Full Fat Audio 10000 series and Traction Control processing featuring NST Audio technology, with an Allen & Heath SQ6 digital mixer on back-end mixing duties.

The program material comprises a series of thumps, ultra-low rumbles and tonal sweeps up to 100hz. Unlike most twin 21” sub configurations, Raptor 221 is designed purely for the most challenging narrow band of ultra-low frequencies within a range of 25-40Hz, while Raptor 218 takes over up to 100Hz: “This configuration provides effortless delivery of the program material without overstretching or wrongly purposing each cab,” said original Traction Sound designer and chief technical officer Billy Wood.

Raptor 218 and 221, of which 20 and 10 of each were used respectively, both utilise bandpass designs, which acoustically filter out any unwanted artefacts outside the desired bandwidth and help to achieve the optimum phase and frequency response, all while avoiding the out-of-bandwidth noise/distortion present in horn loaded systems: “We’re only using a small potential of the Raptor 30-sub bass-array at the Tate so we’d love to let it off the leash at the end in all its glory with the ultra-low distortion Raptor 612 top speakers,” said David Vukovich, CEO at Scicoustic Ltd, a UK company which acquired Traction Sound in 2017. “We’re currently looking for a suitable venue and liaising with various artists to make this happen.”

Scicoustic brings together a highly experienced team in acoustic, mechanical, computational design, material science and manufacturing. Designer and CTO Billy Wood is best known for his decade-long research into air-propagation-distortion and SDS (Soft Dome Source) tweeter arrays, which dramatically reduce high frequency distortion over compression drivers.

“The Tate Modern contains some of the world’s most precious art, with obvious sensitivities and concerns from legal teams representing some particularly valuable and important pieces,” said Brighton Sound System owner Jonny Goodwillie. The company conducted extensive out of hours testing before arriving at a solution, which satisfied the artist and Tate management.

“Brighton Sound System worked closely with consultant sound engineer Ben Caro to construct a solution, which de-couples the stack from the building,” explained Goodwillie. “The design had to encompass safety and stability first and foremost, and this requires rigidity and load bearing materials. The staging on which the PA is built was isolated from the floor by high rigidity load bearing ‘sandwich strips’, which are composed of two layers of hardboard and three layers of a triple layer composite rubber.

“Every time the wave crosses one of the five layers of the sandwich and changes speed it loses energy,” he added. “The resultant effect dramatically reduced structural vibration and kept most of the bass energy airborne.”

So how effective was this collaborative approach from all the parties involved in the project? “This was a challenging project for Brighton Sound System to deliver with multiple parties involved and uncompromising technical and creative requirements from the artist and Tate management,” said Vukovich. “Brighton Sound System and Traction Sound have a long history of collaboration, which certainly helped pull the project together in record time, and both parties have a ‘whatever it takes’ approach to making projects like this happen.”

Vukovich concluded: “Following three years intensive R&D and preparation for all-in-house manufacturing in Wisconsin, USA, we’re excited about the forthcoming launch of all-new Traction Sound systems from November 2018.”