Jyske Bank, DenMaRk
AUDIO MASTERCLASS
Beam forming technology has
the advantage of having no
microphones to interfere with the
placement of laptops and paper
documents on work surfaces
A ‘mega church’ in the US
Banking on good
audio pays off
Installing audio into a meeting room can be something of a challenge. Roland Hemming
explores how this has been done effectively with great skill at Jyske Bank.
The general principle with
sound is that you want as
much audio level coming
into the system as possible
so ideally you want microphones close
to an individual’s mouth. Ideally I’d
provide everyone with a clip-on microphone but this can be impractical as you
then have to deal with batteries and
meeting participants walking off with
them.
The most common approach for
meeting room sound is to place gooseneck microphones around a table. If
budget allows I recommend one microphone per delegate but people can use
one microphone between two. Sometimes a radio microphone is passed
between people when they want to
speak.
Of course the problem with microphones is that they are ugly and get in
the way of people’s laptops and papers.
So people move them further away and
then they don’t work nearly as well. If
you have more people than microphones this may cause problems too.
A number of companies have been
working on solving this problem. Some
solutions hang microphones from the
ceiling but this can cause problems with
sightlines to screens.
A further issue with many conference rooms is poor acoustics – with too
many hard surfaces the sound from delegates and loudspeakers bounces off
walls, floors and ceilings reducing the
intelligibility of the system.
So often we are asked to compromise
so much that the sound ends up being
very poor. The laws of physics require
us to have microphones as close as possible, so some people have been working on breaking the laws of physics and
a few microphone products use line
array or beam forming microphone
technology.
Beam forming tech
This technology is normally associated
with loudspeakers where a directed
beam of audio is fired towards the audience. A beam forming microphone does
the same thing in reverse; a microphone
panel is installed just below the ceiling
or in the centre of a table.
This panel uses an array of many
microphones and it listens to the incoming audio and adapts the inputs it
receives from the many microphone
sources to provide the optimum pickup.
It processes the microphone signals
in realtime and can form a number of
pick-up beams from various people
speaking. This pick-up operates over a
wide area and changes dynamically.
Essentially, it’s an electronic version of
moving the microphone around the
table as different people speak.
This sort of technology can provide a
very convenient and discreet solution
that is trouble free. One problem though
still exists. Because the microphones
are further away, you will tend to pick
up more noise from the room – air conditioning and nearby traffic. So for pure
audio quality a close microphone will
still perform better.
But our case study example for this
NOVEMBER/DECEMBER 2014 | AV MAGAZINE | 45
AUDIO MASTERCLASS
Jyske Bank, DenMaRk
issue progresses things a step further.
Beam forming technology still has a
general pick-up area. But what if you
just wanted a system where you’d just
walk into a room and speak, and everyone else could hear you?
Jyske Bank case study
Jyske Bank in Copenhagen had a room
with less than perfect acoustics and the
need for a flexible meeting space of up
to 75 people.
The Meyer Constellation system was
deployed. This is an unusual application for a technology usually used in
concert halls. Constellation alters the
acoustics of a room. It works with a
series of microphones placed around
the room and two sets of loudspeakers.
One set operates primarily as the PA
system and the other has the sound of
the room played back into it.
By applying signal processing such
as delays or reverberation to this signal
you can change the acoustics of the
room to make it appropriate for the content. The acoustics would need to be
different for a play, rock concert or
orchestral show. You can literally make
the room feel bigger than it is.
In this instance however the technology was employed differently and used
Constellation’s ‘voice lift’ feature. For
this to work for Jyske Bank’s project
the acoustics of the room needed to be
improved so a number of soft surfaces
were installed to reduce the number of
reflections.
Even the choice of furniture can
make a difference. This is important
because you can always make a room
more ‘live’ by artificially adding reverberation to it, but you can’t take it away,
so you want the initial space to be as
acoustically dead as possible. In a con-
ClearOne’s beam forming microphone array ceiling mount
cert hall this gives you a blank canvas
to add any spacial effect needed.
For this project Meyer installed 25
microphones around the room to pick
up any sounds from people speaking.
These microphones sense where the
audio is coming from in a similar way
to a beam forming panel, only across
the whole room.
The microphone signals are then processed and location and direction of the
audio can be determined. The result is
played out of the room’s 64 loudspeakers. However the process is more complex than this because each loudspeaker
receives a slightly different signal
depending on its location and the location of the audio picked up by the
microphone.
Putting it simplistically a loudspeaker very close to the delegate
doesn’t need to amplify their voice very
much as they can be heard acoustically,
whereas a loudspeaker at the end of the
room needs to work harder. In this way
feedback problems are also avoided as
you don’t have loudspeakers trying to
amplify the sound from an adjacent
microphone.
Specialist set-up skills
The signal processing to do all this is
immense and working in realtime at
very high quality. It’s based on some
very sophisticated algorithms and takes
a great deal of skill to set up. Meyer’s
own team carried out this work. The
location of the microphones had to be
set precisely.
To improve performance and flexibility, the system has four presets
depending on the type of activity taking
Jyske Bank has shown that it is possible to have a flexible, good sounding system without microphones in the way
46| AV MAGAZINE | NOVEMBER/DECEMBER 2014
place. These are switched from a standard AMX touch panel: presentation
mode - where the system picks up the
signals near the presenter and reproduces them in the audience area; debate
mode - where the sound is picked up
and reproduced throughout the room,
so everyone may participate in a discussion and be heard easily; conference
table mode - focuses the system on the
sounds from the center of the room; and
small groups mode - uses reverberation
effects to provide acoustical isolation
between adjacent groups.
The Constellation system works
alongside other standard audio inputs
from a video conferencing system, Bluray player and a surround sound processor. It is after all just a PA system.
This extremely complex technology
comes with a price tag to suit and
requires care in how the project is prepared with close co-operation between
the architect, AV integrator, audio team
and client.
It’s not usual to install 65 loudspeakers in a room for 75 people. However
the technology really works and most
importantly, it sounds natural. Each
loudspeaker isn’t working very hard
and they all interact to produce an even
sound in the room. It’s sometimes true
that you need more technology to make
it feel like there is less of it.
However when you consider that the
voice message is the most important
part of any meeting, then people should
put more time, money and care into the
audio element of their installations.
When the audio team is constantly
being asked to compromise by not having microphones in the way then the
overall quality will suffer and it often
does.
Jyske Bank has shown that it is possible to have a flexible, good sounding
system that also doesn’t have microphones getting in the way.
As time goes on, an increasing number of systems will be installed like this.
We will have better acoustic modeling
tools reducing the cost of audio signal
processing and most importantly better
experience by using this sort of technology. This will mean that the price will
drop and effect become increasingly
attainable for a wider variety of customers.
Roland Hemming
is a leading audio
consultant and
project manager. His
experience ranges
from live events to
construction sites, from
manufacturing to installation, corporate
AV, broadcast, and stadia.