Ecophon Acoustic Bulletin

Posted by Marc Janssen at 12:30 PM | Permalink

Mike Barron from the University of Bath, UK, asks himself “when is a concert hall too quiet”? Sound levels in concert halls decrease with distance, but assessment of subjective loudness indicates that loudness judgement is more or less independent of distance from the stage. This leads to the conclusion that listeners compensate their judgement of loudness on the basis of what they see. So people at the back of the hall may compensate for the distance from the source!

Posted by Carsten Svensson at 12:10 PM | Permalink

Alexis Kurtz from Arup Acoustics in New York presented a paper on the issue of sustainable and/or green buildings. She exposed a valuable overview of various green building rating systems globally. Sustainable design covers more than just environmental aspects – it also includes economic and societal benefits, she claims. Acoustics is often not included, leading to poor acoustic conditions in green buildings.

An overview of current rating systems for green buildings:

BREEM
LEED
Green Guide for Health Care (GGHC)
HQE
CASBEE (in English)

Posted by Carsten Svensson at 10:52 AM | Permalink

Ruud Geerligs

The new Dutch Practical Guideline NPR 3438 was recently published and released. This guideline (or standard) covers the field of acoustic ergonomics and gives target values for the room acoustical environment in relation to disturbance of concentration and communication. NPR 3438 can be used for building and housing projects covering building types like offices, schools, sports halls, hospitals etc. Ruud Geerligs from SBR (Building Research Institute) in Netherlands presented a paper on this new Dutch guideline at ICA 2007 in Madrid (19th International Congress on Acoustics) together with Carsten Svensson from Saint-Gobain Ecophon. Ruud highlighted the background and the content of the Practical Guideline in one of the sessions.

Listen to the interview with Ruud Geerligs

Posted by Carsten Svensson at 10:02 AM | Permalink

Markus Oberdörster and Gerhart Tiesler

The acoustic environment of classrooms has a significant impact on new modern teaching scenarios. Today, in many countries, education and teaching is becoming more student centred and differentiated. Classrooms that might have worked well for decades might have to be acoustically “updated”. Markus Oberdörster from Ecophon Germany, together with Gerhart Tiesler from ISF University of Bremen in Germany, spent years investigating the room acoustic conditions of a large amount of German classrooms. Markus talked about acoustics and teaching styles, but also questioned the relevance of Sabine’s formula in non-diffuse conditions and reverberation time as the only acoustic descriptor to use. Gerhart took this further by revealing data on how poor room acoustics has an impact on teacher’s workload, i.e. heart rate as stress indicator. The consequence of acoustically good classrooms is reducing the stressor “noise”, giving higher activation, reducing fatigue and potentially better learning results by the students.

Posted by Carsten Svensson at 9:08 AM | Permalink

An international symposium on room acoustics was held in Sevilla , 10 - 12 September. The event was organised as an satellit symposium to the 19th International Congress on Acoustics in Madrid. Leading experties from all over the world presented "state of the art" in different field of room acoustics. The program consist of 6 keynote lectures and about 75 contributed papers. The main topics of the symposium were

Open air spaces acoustics
Design and room acoustics
Room acoustics simulation
Worship building acoustics

The keynotes lectures cover areas like auditory spatial impression in concert halls, the important role of the seat rows of the Hellenistic Theatre of Epidaurus, acoustics in churches, coupled rooms, room acoustics in virtual reality and finally, room acoustic simulations of multi-source environments. The first keynote lecture given by prof. Masayuki Morimoto was an excellent presentation of spatial and temporal structures and spectra of reflections on auditory source width and listener envelopment.

Saint-Gobain Ecophon AB presented two papers at the symposium concerning classroom acoustic:
Classroom acoustic measurement and evaluation, Nils-Åke Andersson and Erling Nilsson. Download file
Sound decay and steady-state level in rooms with ceiling treatment, Erling Nilsson and Nils-Åke Andersson. Download file

Posted by Erling Nilsson at 8:41 AM | Permalink

Emma Greenland, Bridget Shield, Markus Oberdörster

Listen to a caption of Markus Oberdörster's presentation on classroom acoustics:

Posted by Marc Janssen at 3:07 PM | Permalink

Alternative room acoustic descriptors for open offices
- progresses in standardization
Pierre Chigot, Saint-Gobain Ecophon SA, France

Pierre Chigot, Saint-Gobain Ecophon France

Pierre Chigot explained us about the limitations regarding the use of Reverberation Time for acoustical assessment of open-plan offices. Large variance between measurement positions at low frequencies and poor reactivity to changes in the acoustics due to the lack of diffusivity of the room is often seen.

As potential new acoustic descriptors in open offices the sound propagation from workstation to workstation, rate of spatial decay per doubling of distance (DL2) was suggested. DL2 has originally been applied to workrooms (through EN ISO 14257).
DL2 seems to be a consistent and reliable descriptor of open plan office acoustics and is now included in sound quality standards for buildings. A standard for field measurements of DL2 is needed, taking into consideration the physical characteristics of open plan offices, as well as speech characteristics (increased energy contents at low frequencies, voice levels, raised hearing sensitivity at high frequencies, etc).

Posted by Marc Janssen at 11:37 AM | Permalink

During the conference several persons are interviewed, some of them we even filmed. You can listen to or read the available interviews already and some movies taken during lectures will be available as well.

Check for updates regularly

INTERVIEWS
- John Bradley

- Sabine Schlittmeier

- Valtteri Hongisto

- Ruud Geerligs

- Markus Oberdörster

MOVIES
Infromation and availability will follow later

Posted by Marc Janssen at 11:00 AM | Permalink

Have a look at some more summaries on open-plan office acoustics.

"Determination of acoustic conditions in open offices and suggestions for acoustic classification"
Valtteri Hongisto, Finnish Institute of Occupational Health, Turku, Finland

DL2 and “radius of distraction” as the future acoustic descriptors in open offices?

Speech privacy and the distraction efficiency of surrounding speech can be described by the speech intelligibility between workstations. Valtteri Hongisto stated that previous laboratory and field studies have concentrated on two neighbouring workstations while examination should instead concern the whole office space since noise complaints are not restricted to the nearest workstation. A new method to determine the acoustical conditions of the whole office space, including both short and long distances from the speaker was introduced. Through measurements in 15 offices Dl2 and “radius of distraction” were determined as principal descriptors. The measurements included background noise level, spatial decay of Speech
Transmission Index, STI, and spatial decay of A-weighted sound level of speech.

Listen to a caption of Valtteri's lecture

"A new model for acoustic design in open offices"
Jukka Keränen, Finnish Institute of Occupational Health, Turku, Finland

Get inspired by having a look at a new web-based tool to support the design of good acoustic environments in open offices. Jukka Keränen presented a simple tool based on based on measurement results from 15 very different open plan offices. The model takes into account room dimensions, ceiling and wall absorbers, furniture.height, masking sound level and speech effort. The model calculates the A-weighted speech sound level and Speech Transmission Index at increasing distances from the speaker. Finally,the radius of distraction, rD, and spatial decay of A-weighted speech, DL2 are determined. The tool is freely available in the internet and it is very easy to use.

"Open office acoustic design – multi-dimensional case studies"
Fabien Krajcarz, Gamba Acoustique & Associes, Paris, France

A critical issue in open space environments is to ensure that the acoustics supports both communication and confidentiality – often described as the acoustic paradox in open offices. To create this situation the ambient noise needs to be balanced. At the same time sound propagation have to be created by using screens and dividers when employees need acoustic protection but authorize communication when this is required. The lecture presented a model that suggested the calculation of signal-to-noise ratio as an appropriate indicator of the sound environment in open plan offices.

Posted by Marc Janssen at 10:00 AM | Permalink

The world population has been multiplied by 1000 in 10.000 years.

It's obvious that if we want to safeguard the quality of living for future generations, we need to show environmental awareness and take meausres already today. A definition of sustainability is meeting the needs of the present without compromising the ability of future generations to meet their own needs.

“Acoustics ad the UK perspective on sustainable acoustics “
Peter Rogers - Cole Jarman Associates

According to Peter Rogers, associate at Cole Jarman Associates, sustainable acoustics is about appplying the principles of acoustics to remove the problems that obstruct a “One planet” or “sustainable” solution. During his presentation he showed 3 ways representing the UK approach regarding sustainability and acoustics.

• Regulations increasing (BB93)
• BREEAM assessments (download the factsheet)
• Code for sustainable homes

Rogers gave an overview of the situation in the UK and explained about the BREEAM's assessment for the performance of buildings. His answer to the question "What can acoustician do?", was as following.
• educate themselves and those in other disciplines about what we know so far about human aural effects on comfort, health and happiness
• perform research
• create benchmarks
• raise awareness
• share progress

Posted by Marc Janssen at 10:00 PM | Permalink

Sofar, so good.
The postive summer vibrations of the city of Madrid (35 degrees celsius) is definately also reflected on the mood of the participants of the conference. Sofar around 1500 people have registered.

Please find some pictures of the days sofar

Posted by Marc Janssen at 8:19 PM | Permalink

Reported from ICA Madrid

John Bradley - National Research Council, Montreal

Better speech privacy in open-plan offices can be most consistently achieved by a combination of quantitative design procedures and validation measurements, says John Bradley. This has not usually been done in the past because of the lack of convenient design and measurement tools. While signal-to-noise type measures such as the Articulation Index have been used to indicate the amount of speech privacy in North American offices, often Speech Transmission Index values have been used in European offices.

Piere Chigot interviewed John after his presentations
Listen to the interview (preferably use headphones or loudspeakers)

John Bradley presented the relationships among speech privacy measures, their relationships with speech intelligibility scores, and how they relate to the geometrical and acoustical properties of open-plan office workstations. Good acoustical design goals can be set in terms of these speech privacy measures and required optimum ambient noise levels. New computer-based tools to aid in the design and measurement of the speech privacy in open-plan offices can make it possible to more consistently achieve desired results.

Posted by Marc Janssen at 6:43 PM | Permalink

Acoustic environment in Finnish offices, the summary of questionnaire studies
Riikka Helenius, Finnish Institute of Occupational Health

The result from a recent office study including 8 Finnish offices were presented. The acoustical conditions of the 8 offices represented typical Finnish offices. Noise and thermal conditions were experienced as the most disturbing work environment factors. The most distracting sound sources...

were nearby speech and noises from human activities. Noise was most detrimental to cognitively demanding work tasks. People changed their working strategies to cope with noise. The acoustic environment was experienced much more unsatisfactory in open plan offices than in single person rooms. Selfestimated waste of working time due to noise was twofold in open plan offices. Noise is a major work environment problem especially in open plan offices. The relative amount of open areas is increasing in new office buildings. Therefore, the acoustic design should be taken more seriously in future architectural design.

Posted by Marc Janssen at 6:16 PM | Permalink

Reported live from ICA Madrid

Sabine Schlittmeier

Sabine Schlittmeier, psychologist at Eichstätt University in Germany, presented her paper called Background speech varying in intelligibility - Effects on coginitive perfromance and perceived disturbance. Sabine presented three experiments, which tested the impact of background speech varying in intelligibility and/or level on basic cognitive functions (verbal short-term memory, sustained attention, verbal-logical reasoning).

Listen to the interview. (preferably use loudspeakers or earphones)

The results show that highly intelligible background speech of 55 dB(A) impairs cognitive performance. In order to diminish its disturbance impact significantly, a sole level reduction is not enough – an additional reduction of speech intelligibility is necessary. Subjective disturbance ratings, however, value lowering of the background speech’s level to a greater extent than reducing its intelligibility. Furthermore, although cognitive performance coincided during soft and poorly intelligible speech with those during silence, it was still rated as significantly disturbing.
Thus, the experiments demonstrate that objective performance tests and subjective ratings
complement but cannot substitute each other with regard to a comprehensive evaluation of
acoustic office environments and their alterations.

Posted by Marc Janssen at 8:00 PM | Permalink

ROOM AND BUILDING ACOUSTICS SESSION
After the welcoming programme in the morning, the afternoon was filled with a large number of lectures. One of the sessions was about "open-plan office acoustics".

Valtteri Hongisto and John Bradley chairmen of the session on open-plan office acoustics.

LINE-UP OF THE PRESENTATIONS "OPEN-PLAN OFFICE ACOUSTICS"

1. Acoustic environment in finnish offices - the summary of questionnaire studies - Riikka Helenius

2. Work performance and office noise - Do they correlate? - Valtteri Hongisto,

3. Background speech varying in intelligibility - Effects on cognitive performance and perceived disturbance - Sabine Schlittmeier

4. Alternative room acoustic descriptors for open offices – progresses in standardization - Pierre Chigot

5. Determination of acoustic conditions in open offices AND suggestions for acoustic classification - Valtteri Hongisto

6. A new model for acoustic design of open offices - Jukka Keränen

7. Designing and Assessing Speech Privacy in Open-Plan Offices - John Bradley

8. Open office acoustic design - multidimensional case studies - Fabien Krajcarz

9. Acoustic Design in the New Architectural Trend of "Exposed Structures" - Kenneth Roy

Later today you'll find some interviews and summaries about these experts and their lectures!

Posted by Marc Janssen at 9:02 AM | Permalink

THE COUNTDOWN HAS BEGUN
Just a couple of hours to go before hundreds of people will join the start of the International Congress on Acoustics in Madrid, Spain. A full week of acoustics addressing many fields, out of which the Buidling and Room Acoustics will get our specific attention when reporting.

People are about to take their seats and so can you get in front of your computer. As previously mentioned, we will be reporting daily on what happens at the conference. Stay tuned for the first reports, interviews and photo's in just a short while.

TIME TO REGISTER...

While many participants are arriving later today or in the coming days, this afternoon, sunday September 2nd, lots of people have already arrived in Madrid and registered at the Palacio Municipal for the ICA conference 2007.

FIRST IMPRESSIONS OF THE VENUE AND THE REGISTRATION

Participants meet at the entrance of the congress building on Sunday

entrance hall

Posted by Marc Janssen at 7:14 PM | Permalink