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Centre of excellence All images courtesy of Andre Fanthome
The Bangalore International Centre (BIC) has moved into new premises, with acoustic design by Sound Wizard, and Nova and QSC systems throughout. Caroline Moss reports BIC WAS FOUNDED IN 2005 BY A GROUP OF CIVIC leaders, professionals, artists and academics who believed the capital city of Karnataka state deserved a forum for intellectual pursuits, arts and culture. A non-profit institution supported by membership and donations, BIC was inaugurated by former Indian president, the late Abdul Kalam, and was previously hosted by the Energy Resources Institute. Earlier this year, BIC moved just around the corner into new 14,600m2, GRIHA (Green Rating for Integrated Habitat Assessment) premises of its own. Fortunately for Sound Wizard, which was appointed to provide acoustic design services for the new building, BIC’s evident foresight in envisioning the new facility extended to the planning required for its construction. ‘We were contacted by BIC about three years ago; they called us early on in the project so we could get involved with the acoustics,’ explains Didier Weiss, founder of Sound Wizard, which is headquartered in the neighbouring state of Tamil Nadu. ‘The architect, Bijoy Ramachandran, founder of Hundred Hands, is someone we’ve worked with on other auditoriums in the past, so he was pretty open to our suggestions and that helped a lot.’ Seven years in the planning, the new building was funded entirely by donors and members. Sound Wizard worked on acoustic design for the 180-seat auditorium, a large seminar hall, meeting and video conferencing rooms, an art gallery and cafeteria. For the thrust-configuration auditorium, which has been designed to function as a largely acoustic, multipurpose space, the company conceived and manufactured a range of microperforated panels of differing types. ‘The requirements for amplified and acoustic performances are in direct conflict,’ explains Sound Wizard’s Bangalore-based acoustic engineer, Rahul Sarma. ‘Acoustic performances require an amount of reflective surfaces in order to naturally amplify sound within the space.’ Hundred Hands conceptualised a multifaceted, single-surface interior shell, which creates variably spaced air gaps throughout
104 PRO AVL ASIA November–December 2019
Sound Wizard’s Rahul Sarma the auditorium, providing effective absorption across all frequencies and allowing it to function as a multipurpose venue. ‘This solves a common issue in auditorium designs where a fixed air gap from a simple rectangular box results in excess absorption at particular frequencies,’ continues Sarma. ‘Using perforation on the inner wooden shell allows acoustic absorption to remain hidden. Varying the perforation allows mid- and high-frequency energy to be reflected and carried throughout the room, while allowing low-frequency energy to still pass through the shell and be absorbed. This might result in a slightly higher reverberation time compared to the average auditorium, but the main benefit of this design is the ability for unamplified sound to carry through the space.’ Sound Wizard used EASE software to design the sound system, placing speakers on the stage at human head height to simulate people talking, singing or playing an instrument
onstage. The angles of the wall and ceiling panels were adjusted and angled to reflect the sound created onstage. After many iterations involving input from the architect, the overall geometry of the space was finalised. From here, the amount and location of perforation in the various panels had to be determined. By differentiating between the first reflection points of the auditorium line array and the ‘speakers’ placed on the stage, Sound Wizard was able to identify the useful and harmful reflections in the auditorium by analysing the bounces on the walls and ceiling. The useful reflections were guided with reflective surfaces with little to no perforation, and the harmful reflections from the line array were treated with highly perforated panels. ‘We were aiming for a perfect integration between natural acoustics and electro-acoustics in our design,’ says Sarma. ‘Sound system integration has been designed as an enhancement of natural acoustics, using a combination of both.’ As the auditorium has been designed to function as an acoustic space, the technology installed has been kept to a minimum. Two small, powerful Maxline M5 boxes from German manufacturer, Nova, have been installed as an L-R system in the auditorium. Sound Wizard chose Nova systems for the auditorium and seminar hall, and also for a portable system, and all were supplied by Rivera International, the manufacturer’s Mumbai-based Indian distributor. The Maxline M5 combines six 5-inch transducers in a line array arrangement with a midrange horn and three Beyma drivers with 1.75-inch voice coils, in a cabinet which is just 53cm high. ‘The small boxes are amazingly powerful, and they also meant we could keep the sightlines clean,’ says Weiss. ‘This is the first installation I’ve done with the M5; I really love working with small drivers because the impulse response is so good.’ Two Nova E218 subwoofers extend the system’s frequency range, providing a transparent system for multipurpose applications.
