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Troldtekt speakers 速

Integrated sound

Troldtekt® speakers – integrated sound Troldtekt speakers are integrated and concealed in the Troldtekt ceiling. No visible cabinet speakers or wires, rather architectural purity and clear lines. Troldtekt speakers are based on modern technology ensuring top-quality sound reproduction. At the same time, the Troldtekt panels provide optimum acoustics in the room, distributing the sound clearly and comprehensibly without any disturbing reverberation.

Troldtekt speakers.............................................................. 2 Technology background................................................. 3    Good sound coverage   

Dimensions........................................................................... 4-5   Speakers   Subwoofers

Case studies..........................................................................6-7    Harbour House    Gammel Rye parish community centre

Service............................................................................................. 8 About us........................................................................................ 8

Published by: Troldtekt A/S 2013 Photos: Thomas Mølvig and Martin Tørsleff Design: Text:,


This is an elegant and discreet sound experience for office environments, cafés and theatres, railway stations and airports – and, of course, for your living room. Read more about Troldtekt speakers on the following pages and take inspiration from the two case studies – the office building Harbour House designed by Kim Utzon and the Gammel Rye parish community centre designed by CUBO. Enjoy!

Technology background Troldtekt speakers are integrated in Troldtekt acoustic panels, so you will not notice the speakers in the ceiling – but you will hear them. A Troldtekt speaker is a Troldtekt acoustic panel with a specially developed NXT panel integrated and concealed in the actual Troldtekt panel. An NXT panel electrical impulses into vibrations which are in turn transformed into sound waves. The sound waves pass through the Troldtekt panel and are distributed throughout the room.

On the back of the NXT panel is a flat cassette which protects it against dust, impacts, gnawing mice and other threats.



is a complete flat speaker unit which transforms

Troldtekt speakers can be connected to regular amplifier equipment with radio, CD, iPod or mixer/microphone systems. To ensure optimum sound reproduction in the > bass spectrum, we have developed a special subwoofer. The low subwoofer height of only 13 cm (+ 5 cm for connection cables) enables placing of the subwoofer above the ceiling panel or e.g. under a sofa.

GOOD SOUND COVERAGE It is important for good sound experience that the

tire ceiling surface, which ensures sound signals of

sound reaches every corner of the room. In traditional

uniform volume throughout the room. Traditional cabi-

speaker systems, the sound is emitted from a few

net speakers often offer directional characteristics of 75˚ 75˚

points, often resulting in the experience that the sound

approximately 75 degrees whereas the speaker panels

pressure is high and close to the speakers but then

in a Troldtekt acoustic ceiling have directional charac-

quickly subsides to become weak in the most remote

teristics exceeding 170 degrees. This ensures that the

corners. In other words, the sound is unevenly distri­

sound signal from the acoustic panels is evenly distrib-

buted throughout the room. For example, this situation

uted across the entire ceiling surface and always within

is familiar in airport terminals and railway stations,

hearing range. This also means that the sound pressure

where you need to be close to the speakers to be able

may be generally lower than in traditional systems

to understand any messages.

where it may be necessary to turn the volume up especially loud to make sure that the signals reach every

In a Troldtekt acoustic ceiling with integrated speakers,


the speaker panels are evenly distributed over the en-








Dimensions To achieve an optimum sound experience in a room, it is important for speaker units and subwoofers, if any, to be dimensioned correctly in relation to the room in question.

DIMENSIONING – SPEAKERS Several factors affect the sound experience in a room

2.5 m, it may be necessary to increase the number of

and must be taken into consideration when calculating

speaker panels to ensure good sound pressure distri-

the quantity and distribution of speaker panels in the

bution, while at ceiling heights above 8 m, it may be

ceiling, to ensure as uniform a sound pressure as possi-

necessary to increase the number of speaker panels. In

ble. Troldtekt will be happy to provide advice on dimen-

situations with smaller requirements for sound pres-

sioning of speaker units and to carry out measure-

sure distribution or speech intelligibility, the number of

ments for project planners.

speaker panels can be reduced.

Some of the factors affecting dimensioning are:

Reverberation time

  Speech intelligibility and sound pressure distribution

The longer the reverberation time in the room, the

  Room geometry, particularly the ceiling height

fewer speaker panels are required to ensure a suffi-

  Room reverberation time

cient sound pressure. However, a longer reverberation

  Background noise

time will reduce the speech intelligibility so you should therefore strive to reduce the reverberation time below

Speech intelligibility and sound pressure

0.6-0.9 seconds, depending on the nature of the job.


The Troldtekt ceiling has high sound absorption and

A high level of speech intelligibility requires a good

efficiently reduces the reverberation time in the room.

sound system and good room acoustics with a low reverberation time. A Troldtekt acoustic ceiling ensures optimum sound

Background noise For PA systems in particular, it is important that the

absorption with a low reverberation time in the room.

sound system signal is clearly differentiated from the

Furthermore, the NXT technology ensures that speech

background noise. One way of obtaining this is to

emitted from the speaker panels is perceived clearly

ensure a sufficiently high sound pressure to drown out

and distinctly.

background noise. Alternatively, you can ensure that the sound is evenly distributed throughout the room


so that disturbing background noise does not act as a

At ceiling heights from 2.5 - 8 m, it would be sufficient

barrier between the sound source and the listener.

to have one speaker panel approximately every 30 sq m to ensure optimum speech intelligibility and good sound pressure distribution. At ceiling heights below


Speakers as decoration Troldtekt speakers can also be combined with Troldtekt decoration and are then delivered as framed wall panels.

At ceiling heights from 2.5-8 m, it would be sufficient with one speaker panel approximately every 30 sq m to ensure optimum speech intelligibility and good sound pressure distribution.


Sound pressure and dB

Sound pressure is the generally used method for measuring the power of sound volume. The range perceivable by the human ear – from weak to power­ful sound pressure – is enormous, which is why the decibel scale (dB) is typically used. 0 dB is the weakest sound perceivable by the ear, while the most powerful sounds register around 120-130 dB.

Reverberation time

The reverberation time is an expression indicating how fast sound dies away in a room, e.g. clapping your hands. Specifically, it is the time (in seconds) that passes from the end of the sound impulse until the sound level has dropped by 60 dB.

Speech intelligibility

Speech intelligibility indicates how well speech is perceived in a room – either directly in the room with a speaker and a number of listeners, or via a sound system with a microphone, amplifier and speakers. In its classic form, speech intelligibility is measured by counting how many words are correctly perceived from a text read by an articulate speaker. If the listeners perceive 60% of the words correctly on average, the speech intelligibility is 60% or 0.6.

Subwoofers ensure optimum reproduction of the low bass frequencies below 200 Hz. For systems designed to play music, it is important for achieving good sound that the quantity of subwoofers is correct. Normally, one subwoofer should be provided every 60-120 sq m. As directional determination of the low bass frequencies is difficult, the requirements for even distribution of the speaker panels does not apply to subwoofers. For PA systems, which do not require the same bass volume as music systems, the number of subwoofers can be reduced – or possibly be eliminated entirely.

In our library at, you can find installation instructions for Troldtekt speakers, and also installation instructions for the various types of Troldtekt ceilings.


One of the major construction challenges today is to make good acoustics, architecture and aesthetics come together in synergy. Troldtekt acoustic panels with inte­grated, concealed speakers ensure good acoustics and good sound reproduction while presenting the ceiling as a clean, unbroken surface. In our inspirational section at, you can find a number of exciting case studies and pictures – here are a few examples:

Client: Harbour House A/S Architect: Kim Utzon Architects Engineer: Wessberg A/S

Harbour House Open arms at the port Prime location and architecture characterises Harbour House, headquarters for three shipping companies. The building forms part of the ‘Nolli’ series, designed by Kim Utzon. The U-shaped Harbour House

building’s overall expression. The sound is just there

opens its arms towards the

and there is no visible equipment to disrupt the simple

water. The 8,600 sq m struc-

look of the ceilings”, says Kim Utzon.

ture is one of the long list of

The architect’s own offices are also on the water-

buildings designed by architect

front, at Nordre Toldbod, where he has created an

MAA Kim Utzon. Many of these

inspiring base for his staff of 14.

are located on Copenhagen’s waterfront but Utzon’s touch is also strongly evident in Helsingborg, Sweden

Troldtekt in the signature

and Aalborg, Denmark. Harbour House is the joint

Kim Utzon’s buildings are characterised by a clear choice

headquarters of three shipping companies and the

of simple materials that harmonise perfectly with the

house activities are therefore highly port-related.

overall architectural design. The supporting structures

With so many offices and such intense meeting activity,

are often visible concrete elements – columns, beams

the acoustic environment plays a significant role in the

and T-panels – combining to create a flexible and

building, which is why Troldtekt has been used to

extendable building system that has proved suitable

dampen sound in most rooms.

in many situations. Kim Utzon has also chosen to use cement-bonded wood wool in many of his buildings,

A series of new features

making Troldtekt an important element in his architec-

To ensure good sound and distribution allowing every-

tural signature.

one to hear the speaker, the conference rooms are fitted with concealed Troldtekt speakers. „We used several new features in Harbour House, For one thing, we used integrated, concealed speakers in the Troldtekt ceilings, which fit in nicely with the


Harbour House is the fifth element in the series that Kim Utzon has dubbed ‘Nolli’. This structure forms an urban whole inspired by Giambattista Nolli, who charted Rome around 1750.

Gammel Rye parish community centre Multi-purpose room with sound in every corner The new parish community centre in Gammel Rye, Denmark, is rooted in history and the Troldtekt ceilings fit in well with the building’s rustic character. Acoustic ceilings with integrated, concealed speakers ensure good acoustics and good sound reproduction in the confirmation candidate schoolroom, which also serves many other purposes. Saint Soren’s parish com-

best acoustic panel and the sound properties of

munity centre is located

Troldtekt are well suited for a multi-purpose room

next to Gammel Rye church

such as this”, says architect MAA Anders Kærsgaard

– a beautiful and elevated

from the Årstiderne Arkitekter architectural firm.

location in the Central Jutland Lake District. Whereas

Rustic expression with concealed sound

the church itself dates back

To provide the best possible sound experience in the

to the 15th century and the

large room, four speakers are integrated in the ceiling

brick tower was erected in 1912, the parish community

panels. This conceals the speakers and the sound pass-

centre is newly built. The house was designed by the

es through the Troldtekt panels on its way into the

architectural firm Årstiderne Arkitekter A/S with great

room. This allows the sound to be distributed to every

reverence for the history of this location but also with

corner of the room without the speakers being visually

a present-day twist to show that we are now in the


21st century.

The lobby and administration office also have Troldtekt ceilings and a solution with integrated lighting

Multi-purpose room The most important room in the parish community

in the panels has been selected for this area. „Troldtekt is a rustic material and is therefore a

centre is the confirmation candidate schoolroom which

perfect match for the white-washed walls, the laminat-

fits well in the entire structure with its large corner

ed wood beams and the wide floorboards. The church

window facing the church. The room is used for teach-

council was not easily persuaded because cement-

ing, lectures, choir singing and other activities.

bonded wood wool has a history of use for ceilings

„Naturally, this places considerable demands on the

in livestock buildings. However, now that the building

acoustics in the high-ceilinged room. We therefore

is finished, the logic is clear to them and they are very

chose Troldtekt, because in our experience this is the

satisfied with the project”, adds Anders Kærsgaard.

Client: Gammel Rye church council Architect: Årstiderne Arkitekter A/S Engineer: Søren Jensen A/S


Service provides a clear overview of the

Technical advice

many Troldtekt acoustic solutions. Using our product

We are happy to provide technical advice for construction

generator, you can also download accompanying

professionals. We provide advice on Troldtekt acoustic

AutoCad drawings, a description of the product range

solutions and associated products, including the dimen­

and detailed installation instructions for the chosen

sioning of Troldtekt speakers and we also carry out light

solution. The website also contains lots of inspiration,

and sound calculations for project planners.

among other things a number of reference pictures, case studies and articles about trends.

About us Troldtekt A/S has produced Troldtekt acoustic ceiling

The result is a range of products which are tested

and wall panels since 1935 at Troldhede in central

to meet today’s ever increasing demands for good

Denmark. During this time, the product has undergone

acoustics in a wide variety of buildings.

continuous development and refinement.

International distributors Details of our international distributors are available on

our distributors for general information, brochures They either stock our Troldtekt

or data sheets. You are, of course, also welcome to

products or can obtain them for you. Please contact

contact Export sales at our Head Office in Denmark.

Troldtekt A/S Sletvej 2A 8310 Tranbjerg J Denmark Tel: + 45 8747 8100 Fax: + 45 8747 8111 Email:

Troldtekt speakers