Ecophon Acoustic Bulletin

This very popular session was co-chaired by Valteri Hongisto and J.y.Jeon.

I caught up with Erling Nilsson to discuss an overview of the session after reading his paper. The session consisted of 5 papers, 2 of which were invited papers. 3 of the papers concerned the evaluation of the acoustics and measures related to sound propagation in open plan offices. In particular measures related to sound distribution curves; DL2, DLf & LpA,S,4m.
The 4th paper focused on full scale office in labratory conditions investigating the effect of screen heights, workplace locations and background and masking noise.
The final paper was actually a field investigation of an open-plan school in Iceland

During the session there was a clear concensus of the usefulness using parameters related to sound propagation which are also suggested in the new ISO 3383-3 draft. It was quite clear that the open plan offices are challenging environments and a successful acoustic design is a combination of; building acoustic and interior design issues, planning of the organisational workplace for the activities and use of space, whilst considering management and behaviour.

Open-plan offices are complex environments and simple theoretical modelling is not straight forward, so the use of simulation (ray-tracing) software was quite promising as a way to potetential future analysis in the design process - even though there are other issues in the simulation process which have to be solved concerning angle dependant absorption and defraction.

Generally discussions concerned the overall acoustic behaviour characterised by these sound propagation measures however the acoustical conditions between nearby individual workplaces which is very important for helpdesk activities and was described in one paper by J.Keränen et al. This paper focused on ceiling, wall, and screen absorption as well as screen height, work station and masking noise in a laboratory environment situation.

The final paper in this session highlighted that open-plan spaces is not only restricted to offices but increasingly growing in schools which a field case study presented from Iceland. Similar to offices, the consideration of different activities, their planning and timetabling was important for these premises to work in reality as well as the overall acoustic considerations.

5 papers discussed are listed below ;

Acoustic parameters for the evaluation of open-plan offices.
Erling Nilsson, Ecophon, Sweden.

Acoustic methods in open-plan offices.
Claus-Moller Petersen, Gontmij, Denmark.

Architectural influences on speech privacy in computer simulated open-plan offices.
B.K.Lee, P.J.Lee and J.Y.Leon, Hanyang University, Republic of Korea.

Speech privacy in an open-plan office with different room acoustic conditions.
J.Keränen , J Hakala, D.Olivia and Valteri Hongisto, Finnish Institute of Occupational Health.

Acoustics in an open-plan elementary school.
H.K. Juliusson, Verkis Consulting Engineers, Iceland.

Posted by Colin Campbell at 11:21 AM
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Danish Acoustical Society will host acousticians from all over the world to participate in the 6th Forum Acusticum in Aalborg. This conference is held every three years and provides the opportunity for all acousticians to meet and discuss recent advances in their fields of interest.

This conference will be held from 26 June to 1 July 2011 at the Aalborg Congress & Culture Center. This top class congress centre is located in the heart of the largest green spot of the city.

http://www.fa2011.org/?Welcome">Forum Acusticum 2011 is organised for the European Acoustics Association">European Acoustics Association and will feature a high standard technical program including key-note lectures, invited and contributed papers in structured parallel sessions, workshops and poster presentations. There will also be an extensive technical exposition highlighting latest advances in products for all fields of acoustics.

Ecophon are one of the key conference sponsors, will sponsor the preconference dinner, have Erling Nilsson and Nils Åke Anderson presenting papers and will have a booth in the exhibition area - we hope to see you there!

Posted by Colin Campbell at 4:14 PM
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Drs. Marcus Oberdorster and Gerhart Tiesler from Germany were invited to speak at the distinguished Knudsen lecture at the 161st meeting of the Acoustical Society of America, Seattle Washington, USA.

The research which Markus and Gerhart presented was a combined project looking at "acoustic ergonomics in schools" which looks at classroom acoustic conditions for modern teaching and learning and how good classroom acoustics reduce teacher workload and stress.
Gerhart shares with us how it was received and how it may influence the present noise level upper limits....

Gerhart's comments:

"It was very important to talk about Ergonomics and how to analyse the “workplace school”, to give an idea of analysing instruments that for.
There is a great discussion in the States about upper limits for basic noise level at 50dBA!!!
So our lecture has given the ASA some arguments for lowering this limit against the background of physiological effects by noise below 80dBA, the “low noise”.
There was also a very intensive discussion about importance of good room acoustics for teaching hearing impaired children instead of “sound field systems”, which only will amplify the noise without upgrading the speech intelligence".

More about the papers;
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 who worked with 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 the limitations of 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 “high sound levels”, giving higher activation, reducing fatigue and potentially better learning results by the students.

Acoustic ergonomics of schools

Posted by Colin Campbell at 11:16 AM
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