©00-0410/CSV/EVN Edu 2000 Sound in educational premises Good acoustics are important in improving...

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Sound in educational premises

Good acoustics are importantin improving

the educational environment

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Ecophon

A company with 30 years of experience in how to create a good acoustic

environment for educational premises

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Global Network

Sales company

Distributor

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The ability to concentrate is importantin order to achieve maximum efficiency

in the educational process

Concentration

Energy

Wrongtemperature

Lack of mental balance

Disturbing sound

Bad light

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Classroom conditions:

- The reverberation time is too long

- Too much background noise

If you hear properly life becomes easier

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It is usually the teacher who judgesspeech intelligibility!

But what is the opinion of the pupils?

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Poor Sound EnvironmentLong Reverberation Time

+ High Background Noise Level

= Poor Speech Intelligibility

Teachers• Stress and strain• Voice and throat

problems• Headaches

• Days off sick

Pupils• Lose interest and

concentration• Cannot hear what the teacher says

Working Environment

Learning Environment

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Absorption classes - EN ISO 11654 p Practical absorption factor

Absorption class A

Absorption class B

Absorption class C

Absorption class D

Absorption class E

Unclassified

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125 250 500 1000 2000 4000Frequency Hz

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Over 70 teaching spaces investigated during three yearsPrimary schools

Schools containing hearing impaired children

The schools covered a range of styles, ages and locations

Classrooms with and without acoustic ceilings

MeasuredSound pressure levels

Reverberation times

Speech intelligibility

- STI

- %ALcons

- WIPI

Classroom environment survey

Research projectHeriot-Watt University, EdinburghDepartment of Building Engineering and Surveying

(D.J. MacKenzie, R.J.M. Craik and S. Airey)

Classroom acoustics

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Sound Pressure Level - Teacher Talking

Decibel Untreated classroomsTreated classrooms

Heriot-Watt University, Edinburgh; Classroom Acoustics; D. MacKenzie/S. Airey

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Sound Pressure Level- Pupils Quiet


Untreated classroomsTreated classrooms

Decibel

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Sound Pressure Level- Pupils Talking

Untreated classroomsTreated classrooms


Decibel

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Results - Sound Pressure Levels- Rathmore Primary School

Untreated Treated classrooms classrooms Comments

Pupils quiet 42 dB(A) 39 dB(A) Decrease of sound propagation (3 dB)

Pupils talking 74 dB(A) 64 dB(A) Decrease of sound propagation (3 dB)and noise generation (7 dB)

Teacher talking 58 dB(A) 52 dB(A) Teacher using lower voice level


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Results Reverberation Time


Reverberationtime, s Untreated and empty

Untreated and occupiedTreated and emptyTreated and occupied

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Results Speech Intelligibility - STISpeech Transmission Index


Untreated Treated

0,50 0,70

STI Response Scale

0 - 0,30 Bad0,30 - 0,45 Poor0,45 - 0,60 Fair0,60 - 0,75 Good0,75 - 1,00 Excellent

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100% loss of consonants

-o-e --a---oo-- -a-e -oo- a-ou--i--

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100% loss of vowels

s-m- cl-ssr--ms h-v- p--r -c--st-cs

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Results Speech Intelligibility - % ALcons

(Percentage Articulation Loss of Consonants)

Untreated Treated

13,7% 4,6%(Average percentage articulation loss of consonants

for all of the classrooms tested in the projects)

Heriot-Watt University, Edinburgh; Classroom Acoustics; D. MacKenzie/S.Airey

Recommended %ALcon scale

>15% Not acceptable except for very simple or well known messages15-10% Acceptable for general messages of low complexity10-5% Good<5% Excellent

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Table 1: % Alcons values for a classroom (before and after Ecophon Acoustic treatment)

Location % Alcons %Alcons Comment(within class room) (before treatment) (after treatment) (acceptable value - 5%)

1 9.5 4.0 Improvement 2 9.4 3.0 Improvement 3 6.6 7.3 Slight increase 4 4.7 2.3 Improvement 5 74.4 3.4 Improvement 6 11.2 3.4 Improvement 7 10.2 5.0 Improvement 8 14.6 4.0 Improvement 9 13.7 10.5 Improvement10 99.0 4.4 Improvement11 7.9 4.1 Improvement12 12.6 2.8 Improvement13 100.0 3.7 Improvement14 6.7 3.9 Improvement15 100.0 3.7 Improvement16 7.1 6.4 Improvement17 79.5 5.6 Improvement18 87.0 5.3 Improvement19 100.0 8.1 Improvement20 92.0 13.2 Improvement21 11.5 3.4 Improvement22 12.7 5.3 Improvement23 8.9 2.7 Improvement24 5.9 3.9 Improvement

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Different shapes

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Results Speech Intelligibility: WIPI

Ring Wing King Swing String Spring

Untreated Treated

Control 96.7% 97.5%

Quiet classroom 94.2% 97.5%

Pupils working 57.2% 67.0%


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Summary

Classrooms treated with acoustic ceilings

•Background noise level reduced

•Reverberation time reduced

•Improved speech intelligibility

•Creates a greater ease of communication and increased performance

•Pupils’ attitudes and behaviour changed

•Working and learning environments improved


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Listening test - Lund University

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9 different absorption cases9 different absorption cases

Listeners tests on a scientific level

Listeners tests on a scientific level

Two test groups:- With normal hearing- With slightly impaired hearing

Two test groups:- With normal hearing- With slightly impaired hearing

To statistically secure a ranking

To statistically secure a ranking

Lund University, Listening test, P. Hammer/E. Nilsson

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Ranking list

Ceiling 7 = Class A (+) absorber + sound absorbing notice boardon the back wall

Ceiling 8 = Class A absorber + sound absorbing notice boardon the back wall

Ceiling 9 = Class A absorber

Ceiling 6 = Class B absorber

Ceiling 2 = Class C absorber

Ceiling 1 = Class C absorber

Ceiling 3 = Class D absorber

Ceiling 4 = Class D absorber

Ceiling 5 = Class E absorber


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Conclusion

Listener’s choice

Class A absorbersin the whole ceiling


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Recommendation in classrooms

Ecophon Master

Wall absorber Super G

Master Alpha

Master Gamma

In classrooms longer than 9 m- absorber onthe back wall

The whole ceilingcovered by soundabsorbers class A

A reflector forthe comfort of

the lecturer

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Ecophon Master

Akutex®-T surface which meansUnique sound absorption properties

High light reflection (84%) and light diffusion (87%)

Cleaning: Wet cleaning

Surface Absorption class

Master alpha AMaster beta C Master gamma E

Master A, t kh 200 mm

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- Acoustic ceilings -

Fire safety

Light efficiency

Accessibility

Cleanability

Handling mechanical

strength

Loading

Environmental impact

Acoustics

Moisture resistance

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Nordic SwanThe products fulfil the Nordic

environmental demands during the totallife time - from production to re-usage

Glass recycling70% of the core material in

Ecophon products contains ofrecycled glass containers

REPAEcophon is a member of REPA, who

administrates the recycling of packingmaterial from sites

Dansk Indeklima MaerkningThe products fulfil the best class, 10 days,

regarding degassing single substances to dropbelow threshold levels

RecyclingThe oxymelt process, is a

melting process that recycles old products

Swedish Asthma and Allergy Association

Ecophon products have been examined and are recommended

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Summary

A good acoustic performance is one of the conditions

necessary to improve the educational environment

• gives the listener a fair chance

• increased efficiency in the learning process

• less fatigue, stress and strain

• less frustration

• increased sense of well-being

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Literature referencesAudiology. Magazine, France.

“Effect of Sound-Absorbing Treatment on Speech Discrimination in Rooms.” No 29, 1990. Eeva Pekkarinen, Vesa Viljanen.

Community noise.

Environmental Health Criteria Document. WHO. 1993

Ear & Hearing. Magazine, USA.

“Speech Recognition in Noise by Children with Minimal of Degrees of Senorineural Hearing Loss.” 0196/0202/93; 1993. Carl C Crandell.

L’Acoustique des Loceaux Scolaires.

A French investigation regarding acoustics in schools. 1994

Noise/News International.

Magazine, USA. “Effects of Noise on People.” June, 1993. Henning E von Gierke, Kenneth Mck Elred

Classroom Acoustics.

A research report (1999). Heriot-Watt University, Edinburgh. Department of Building Engineering and Surveying. David J. Mackenzie & Sharon Airey

Listening Test

Lund University/Lund Institute of Technology. Department of Engineering Acoustics. Erling Nilsson & Per Hammer

©00-0410/CSV/EVN Edu 2000 Sound in educational premises Good acoustics are important in improving...

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Transcript of ©00-0410/CSV/EVN Edu 2000 Sound in educational premises Good acoustics are important in improving...