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Measurement
using dodecahedron (12-sided loudspeaker) in the concert hall of Artisten,
Gothenburg. |
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Electroacoustics and AV technology
Akustikon
has wide experience of planning AV systems. We specialise in electroacoustics.
In recent years, we have also planned a large number of complete AV systems
with audio, video, lighting and control functions. We also have solid
experience of electroacoustical measurement and inspection of AV systems.
Planning
When planning AV systems, there are many technical requirements that must
be met. We perform aesthetic and technical integration of the latest innovations
in sound, video and control techniques. On larger projects, we sometimes
also collaborate with lighting and stage technology consultants. Simple
user function is vital for good end results, and we place strong emphasis
on designing user-adapted interfaces. We can design easy-to-understand
documentation for decision-making and cost calculations for the users
before detailed technical specification and basis for quotation are issued.
Other important elements of the technical description are requirements
regarding system documentation and user training.
Acoustical engineering
In many of our major projects, we have also been in charge of planning
the room acoustics. The interaction between the loudspeakers and the room
is vital to the final acoustic result.
Besides conventional systems, we also have expertise
in several advanced electronic directivity systems, reflector systems
and reverberation systems, such as Outboard electronics TiMax, Duran Audio
DDC (Digital Directivity Control), ACS DSE (Direct Sound Enhancement),
LCS SpaceMap, LCS VRAS, LARES, ACS, Carmen and SIAP.
Computer calculation
For loudspeaker calculation, we use two software
programmes for acoustical measurement: CATT and RAYCALC. Both programmes
create a 3D model of the space, and the directivity of the loudspeakers
is fed in. It is possible to use several loudspeakers with various delay
times. With CATT, it
is also possible to simulate clusters with in-phase addition of the loudspeakers
used. In such cases, interference between the loudspeakers is taken into
account. We have used both programmes in numerous projects, both for loudspeaker
calculation and room acoustical calculation. We have been using RAYCALC,
a programme developed by us, for over 15 years.
To our knowledge, we are the only company to have extensively
published comparisons between predicted and
measured values. At the 1995 International Congress on Acoustics (ICA)
in Trondheim, Norway, we presented over 67 comparisons (positions) in
8 different halls. We have also participated in an independent Round Robin
test prepared by Professor Forländer at the Physikalisch-Technische
Bundesanstalt in Braunschweig, Germany. The results showed a high level
of agreement between predicted values derived with RAYCALC and actual
measured values.
Both programmes are able to calculate all significant
acoustic parameters. We also use CATT for auralisation (cf. visualisation),
i.e. listening to the calculated results. Auralisation is a useful complement,
since the existing criteria are fairly approximate. We have used auralisation
in many projects in recent years, and are familiar with its possibilities
and limitations.
Listening
tests
At Akustikon, we are well aware that technical requirements are not enough
to describe the acoustic quality of a room. For this reason, we also perform
listening tests. Through our research, we have gained experience in the
planning and analysis of subjective tests. In several of our projects,
we have planned and performed controlled test listening of loudspeaker
systems, for clients including the Gothenburg Opera (GöteborgsOperan),
the Old Music Academy (Gamla Musikaliska Akademien) (Nybrokajen 11, Stockholm),
and Växjö Concert Hall (Växjö Konserthus).
Video
and control engineering
We
favour goal-directed planning. In other words, we develop the technical
solutions that are really necessary to produce the required AV functions.
This working philosophy makes it easier to rank and prioritise the functions
and the equipment used for them.
With regard to video solutions, we use the latest technology
for front projection, back projection or plasma panels. The high light
intensity of today's projectors makes front projection an attractive solution,
while plasma panels (currently sizes of up to approx. 60") can be
used to achieve maximum contrast and insensitivity to room lighting. We
adapt the positioning of screens and data/ OH projectors to the relevant
visibility and image size requirements. These factors often influence
the layout of the room, the presentation wall and the audience seating.
For this reason, early involvement in the planning is vital in order to
achieve optimum results.
In many cases, practical tests known as "shoot-outs",
using several alternative projectors, can help the user determine which
projector properties are vital in determining the quality of the image.
The same method can be used for choosing electronic document cameras,
the best of which can sometimes be used in place of traditional OH projectors.
User handling and picture quality are vital factors in this evaluation
process.
The latest technique using pressure-sensitive plasma
panels offers the user new interactive options. The user can use the screen
as a simple whiteboard or superimpose written text on the computer image.
The final result is saved as a file that can easily be printed. The screen
can also be used as a touchscreen for controlling the equipment in the
room.
We normally use a multi-functional control system, whereby
several functions can be controlled simultaneously. The user controls
the system by means of a touchscreen with a menu system, or, in easier
systems, through standard pushbuttons. Shows and theatrical performances
require a control system with time- as well as event-based control functions
(a show control system). In our planning, we can create simulations of
the touchscreen's function and layout so that the user can try working
the system early on in the project. This allows the user to practice using
the system and assess its manageability.
Adjustment,
measurement and inspection
We have wide experience of the adjustment and measurement of sound systems.
We use sound level meters, real time analysers and the MLSSA
and WinMLS measurement
systems. We have also participated in a joint Nordic project, producing
the new proposal, "Measurement methods for testing and quality control
of electro-acoustical systems" for NORDTEST,
and has presented articles for conferences on room acoustical measurement
technique.
We have inspected sound and AV systems for numerous
projects. We have also been engaged to solve various problems. This has
given us valuable user feedback, as well as experience of common practical
problems and how to solve them.

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