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Powersoft Modules Drive Unique Wall Of Bass

Powersoft D-Cell504 IS high power amplifier modules have been specified to drive a unique ‘Wall of Bass’ in an Austrian nightclub - as low as 7Hz.

The newly-reconstructed Club SUB, in the city of Wiener Neustadt, set out to integrate a perfect low frequency solution, capable of reproducing a wide range of live and DJ-derived music (drum ‘n’ bass, dubstep and techno) and arts presentations, as well as workshops and theatrical performance in a completely revolutionary way.

And since the 300-capacity SUB is located in a heavily populated residential area heavy, emphasis needed to be placed on acoustic isolation to avoid noise pollution.

Project Managers, Wolfgang Sauter (from pro performance) and Reinhard Nell (from Lambda Labs), were equal to the challenge.

Speaking of the background to the project, Lambda Labs German-based Director, Steffen Kroschel, said: "The owners’ goal was to achieve a similar sound performance as it had in the Grelle Forelle Club in Vienna. Given the concerns of local residents, when Mr. Sauter surveyed the building, with its tube like architecture, the abstract idea of a vibrating wall became more logical."

He contacted Lambda Labs where Richard Nell supported the concept with simulation data, parameters and measurements - applying his knowledge of high performance concrete ‘closed box’ enclosures and amping. The drivers were developed especially for this application, going through 10 prototype stages, while the club owners helped with casting the concrete loudspeaker enclosures.

For the rear wall, behind the six by five metre stage, 400kg special concrete blocks were cast and set into a six by three metre wall, using 13 tons of heavy concrete and a further 35 tons for the foundation - requiring a monumental effort. "It was extremely difficult to handle these enclosures with small forklift trucks and build the 50cm deep low frequency absorber," recalled Steffen. "Behind the wall is sand, and under the wall, Mr. Sauter chose material that is used for highway construction."

Each concrete block serves as loudspeaker enclosure with pressure-resistant rear chamber which implements the perfect impulse response of a ‘closed-box’ design and maximizes the radiation resistance of the woofers through the acoustically hard surface. A self-enveloped 15-inch speaker was produced and adapted to the unusual demands of this project. The single chassis are designed to act together like one single swinging wall - in a similar principle to a piston in a cylinder.

Steffen explained the concept further: "A perfect plane wave is created in the interior of the club, which naturally moves along the side walls and doesn’t induce any room modes. The rear of the main floor was converted into a single bass trap to absorb the incoming wave. The SUB thereby achieves an acoustical result that could never be reached even outdoors."

And as for outside, there is virtually no noise escape and both Reinhard Nell and Wolfgang Sauter, agree that "such an operating range and evenness of the low frequencies is overwhelming."

But to achieve this optimum performance, every driver needed be powered by its own dedicated amplifier module to take advantage of shortest cable runs, perfect matching power supplies and impedance data. As a long-term partner of Lambda Labs, Reinhard Nell chose Powersoft to provide amping for the ‘Wall of Bass’ while Lambda Labs supported the installation with items like amplifier mounting frames.

"As we have been using Powersoft amplifiers in our regular self-powered loudspeakers for four years, it was obvious to choose the company again for this project as we have a lot of experience with their modules, such as the Digimod 1500, which we use successfully in our subwoofer product MF-15A and our full range enclosure TX-3A," continued Steffen.

The 32 Lambda Labs OEM CX 15-inch ultra-long excursion drivers, with 25mm linear excursion capability set in housings made from special concrete. Each is driven by 800W amplifying modules, with the maximum desired SPL reached at an excursion of only 3mm. Therefore the ‘Wall of Bass' manages with only 500W peak music power during operation, which sets new standards of energy efficiency.

Performance is enhanced via PFC power supply, allowing error proof operation, and premium quality Class D output stage, also available with DSP on board.

Summing up, Steffen Kroschel says that everyone who has played through the system has been hugely impressed. "For some it has changed their awareness of music."





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