ACOUSTICS
absorption in a hall makes the music sound
dull,” says Adelman-Larsen. “I only understood
why years later, when I saw a study by a research
group at Aalto University in Finland: when
their playing volume increases, most musical
instruments, including vocals and guitars,
increase their high-frequency content more
than their low-frequency content.”
If the hall doesn’t respond to that, then
the musician can’t feel the dynamics they
are trying to express, and neither can the
audience. “This is why some musicians,
when playing in an overly dampened hall,
feel that it is unresponsive, like hitting
a pillow,” says Adelman-Larsen. “Music
is all about feelings, and they really aren’t
evoked in such tame acoustics. Further,
in that type of room, the musicians and the
audience have a hard time hearing the audience
cheering. This is not ideal when they attended
the concert to experience a great-sounding,
touching, social event.”
Making magic
For a musician, the acoustics of a hall are
a natural and genuine extension of their
instrument. “Getting the acoustics right is the
basis for the moment we are all striving for:
when the music unites musicians and audience,
enveloping them in sound from all directions,”
says Adelman-Larsen. “With the acoustics
appropriate for the type of music, professional
musicians are capable of creating this magic
at every concert, in any hall.”
It was his love for music, and in particular
this special moment of unity, that compelled
54 AUDITORIA 2019 VOLUME ONE
Adelman-Larsen to invent variable acoustic
technologies that could ensure the acoustics were
right for any type of music in any hall at any
time. The first fruits of his work were the aQflex
and aQtube products, which are in use at various
venues around the world. More recently, Flex
Acoustics developed Evoke, which can reduce
the RT of a hall by 50% at low frequencies (to
ensure the hall does not rumble at pop and rock
concerts) while at the same time absorbing less
high-frequency than low-frequency sound (to
ensure vivacity). The patented technology can
be mounted on both ceiling and wall areas.
Unobtrusive aesthetic
Evoke not only adjusts the hall acoustically to
fit any genre of music, it is embedded in wall
and/or ceiling surfaces, making it “invisible”
in the hall, Adelman-Larsen says. The Evoke
system is composed of several 240 x 60cm
(94.5 x 23.6in) modules, which can be finished
in wood or lacquered steel. These are mounted
side by side to form large, unbroken surfaces,
such as entire walls or ceilings.
The front face of each module has four
slats which by means of a flap can be opened
or closed. When the slats are closed, sound is
reflected, and when they are moved aside sound
is absorbed. This enables halls to switch between
configurations to provide the ideal acoustics for
each musical genre. The hall looks exactly the
same regardless of which setting is chosen.
Adelman-Larsen says a few halls are now
looking to incorporate the technology. The first
installation of Evoke will be at the acoustics lab
at Aalto University in July 2019. The technology
will enable the lab to alter its RT from 0.5 to
2.0 seconds in the 125Hz octave band, while
impacting other frequency bands as well. n
www.flexac.com
Above: An aQtube installation
in use at Amsterdam Arena in
the Netherlands
Below: Niels W Adelman-
Larsen, CEO of Flex Acoustics
Artists
including
Beyoncé,
Coldplay, U2,
Rihanna and
Kraftwerk have
all performed
underneath a
Flex Acoustics
invention
/www.flexac.com