Andermatt Concert Hall Delivers Intimate, Acoustically-accurate Performance Experience with Renkus-Heinz

	Andermatt Concert Hall. Photo: Roland Halbe

The Andermatt Concert Hall, located in the village of Andermatt in the Ursern Valley of the Swiss Alps, opened its doors in 2019 to rave reviews by hosting the Berlin Philharmonic, bringing world-class classical music performance to the alpine wonderland.

The concert hall is a beautiful venue with seating for up to 650 and offers an up-close and intimate atmosphere with enough room for a 75-piece orchestra. The hall's stage and lower level are below ground level, and the space features a high ceiling with upper-level walls of glass, wood-finished ceilings, and a wrap-around balcony. Studio Seilern Architects created a captivating space, integrating acoustically optimized "origami" panels to provide an immersive, lively acoustic in every seat. A new enhanced acoustic system was also deployed to increase the subjective volume of the space for varying performances.

To address acoustic challenges, Andermatt Swiss Alps brought in KahleAcoustics, specialists in space acoustics for concert and performance venues, and Amadeus Active Acoustics, developers of the Amadeus multi-channel, active acoustic and immersive sound system. They were challenged to design and deploy a high-quality sound system that was both accurate and natural. To do this, the team used 75 CX41 loudspeakers and eight CX/CA118S subwoofers from Renkus-Heinz to cover the performers and audience.

Evan Green, acoustician associate at KahleAcoustics, says the challenge with a large orchestra, especially in a relatively small space, is how to control the sound level from being overwhelming. The sound pressure level generated by a full orchestra in a concert hall is enormous.

"Once you have a fixed volume, the way you make it quieter is to add sound-absorbing elements and surfaces," Green says. "But when you do that, the room becomes less reverberant, less resonant and the sound has less life to it, so we recommended a room enhancement sound system approach."

A room enhancement system involves installing many loudspeakers that fully surround the audience to create an enhanced version of the hall's acoustics. In the case of the Andermatt Concert Hall, the immersive sound processing system from Amadeus Active Acoustics uses 32 microphones to pick up all sound within the hall. Those signals are individually processed with natural active acoustic algorithms and then routed to the discreet Renkus-Heinz loudspeaker and subwoofer channels.

"Our ultimate goal is that the performers and audience are never aware that any of this is happening," says Fabio Kaiser, principal acoustician, Amadeus Acoustics GmbH. "The space simply sounds like the natural acoustics of the room, but it's created in a way that doesn't add to the loudness issue. The natural acoustic character is still very present, and the scale of the room is expanded and enhanced by the active acoustics system."

Seventy-five Renkus-Heinz CX41 speakers are strategically installed throughout the hall. The speakers are color-matched with the walls, wood accents, and ceilings. They are also located behind acoustically-transparent screens, making them virtually invisible, the company says.

The CX41 is a highly adaptable, compact, 4", two-way, non-powered loudspeaker featuring a versatile enclosure design, go-anywhere hardware, and rugged construction. This full-range, miniaturized enclosure delivers a very accurate, 100Hz to 20kHz frequency response and a wide 150-degrees H x 150-degrees V dispersion.

"The sound quality, size, width of dispersion pattern, and frankly, the affordability of the CX41 loudspeakers make them a perfect choice for this application," says Kaiser.

To support the loudspeakers, a set of eight Renkus-Heinz CX/CA118S 18", high-performance subwoofers are installed. These subwoofers provide the high-impact sub-bass energy needed in many venues. These non-powered subwoofers feature an accurate and natural 35Hz to 100Hz frequency response.

"It's important for musicians to feel that they're inhabiting the same space as the audience, so we need to make sure every direction is covered, and everyone gets sound from every direction, so they feel completely enveloped in sound," says Kaiser. "When you attend a performance at Andermatt Concert Hall, the system is on, but it just sounds like the natural sound of the room. Extremely high-profile musicians have performed here who been astounded by the active acoustics in place."

Green agreed that the Andermatt Concert Hall managers, performers, and audiences alike have been very impressed with the system.

"This turned out to be the best solution possible for this hall. We now have good speech intelligibility for conferences and banquets, as well as excellent quality, resonance, and an enveloping acoustic environment for classical music," says Green. "I look forward to working on more projects with Renkus-Heinz products."