evoke – new technology for variable acoustics

video   Short video presentation (1:23 min)

video   Real-life installation (0:22 min -remember sound ON)

  ‘Lille Sal’: concert hall case description (pdf)

  Sound lab case description (pdf)

New possibilities in music hall design

The evoke is a powerful variable acoustics technology which transforms a hall acoustically in 5 seconds to accomodate any style of music – with barely any visual change.

Using the evoke technology multipurpose halls can present a wide variety of styles of music with literally optimal acoustics: from choir, chamber music over brass bands to rock concerts and even cinema. All with ideal reverberation time in every frequency band to ensure an optimal sound experience and performance.

The system consists of numerous modules that are embedded in large, or entire ceiling and wall surfaces. The module is the basic building block and can be angled to ensure a more sound-diffused room.

Each module is 240 x 60 cm, has a dedicated low voltage motor and can be:

  • open to absorb sound = short reverberation
  • closed to reflect sound = long reverberation

These variable modules are connected in groups – for instance 4 groups. There is one group (preset) for each basic style of music to be presented. However, there is no limit to the amount of groups that can be allocated a system. Each single module could be operated individually.

Panels of any  surface finish, such as wood, can be mounted flush to the variable modules. Or e.g. 3 dimensional surfaces made of sound transparent fabric can be allocated in front of the modules. This all renders a high degree of design freedom for architects and designers.

 Certified measurements in reverberation chamber

 Read brochure

The technology was developped with Innovation Fund Denmark (Danish Ministry of Higher Education and Science) and is patented.

The surface panels can have various perforation patterns chosen by acoustical consultants and architects with for instance curved slits or slits narrower than the width of the openings in the variable modules – or have a sound-diffusive topography.

Walls and ceiling, or parts of them, become fully absorptive or reflective, at the flick of a switch. An acoustic consultant can chose exactly which panels should be open/closed in the various presets. Designers can think of the evoke module as a basic building block and can design odd angled-surfaces etc. The imaginary spaces on the renderings here on the page merely give an idea of colors and basic looks. Feel free, as the acoustic designer or architect, to come up with ideas to how you might want to use this new building block: the evoke module. The possibilities are vast…

The evoke system can come with an optional service package which ensures a lifespan of at least for instance 40 years.

video  Explanatory video (4:30 min)

“The name ‘evoke’ was chosen since, to the best of my knowledge, the technology really helps the performing musicians to evoke music – regardless of genre. The absorption curve is chosen very deliberately.

It has gradually become a well-known fact, largely due to Flex Acoustics founder Niels Adelman-Larsens research, that amplified music needs a controlled bass reveberation, but less commonly appreciated, that the hall shouldn’t be irresponsive at high frequencies. This is substantiated in his latest peer reviewed article: Investigation on acceptable reverberation time at various frequency bands in halls that present amplified music.

Please read more in the section: acoustical/research papers.”

Kind regards
Niels Adelman-Larsen, musician, acoustician