Modern School Acoustics - Ecophon
Modern School AcousticsOn teaching styles, room acoustics, teachers'health and pupil behaviour
Modern School Acoustics on teaching styles,room acoustics, teachers’ health and pupilbehaviourBy Dr. Markus Oberdörster, Ecophon Germany and Dr. Gerhart Tiesler, Institut für Interdisziplinäre Schulforschungder Universität Bremen (Institute for interdisciplinary school research of the University of Bremen, Germany)1. Noise in schools – currentstatus of school researchSchools have become much noisierin recent years, with the numberof complaints about this steadilyincreasing. In 1999, a study bythe ISF (Institute for InterdisciplinarySchool Research) of the Universityof Bremen, with about 1,200teachers participating, gave a veryclear picture of the stress factors thatarise in schools. When questioned,more than 80% of those taking partadmitted experiencing stress caused"I am stressedby the noisethat pupilsmake."by pupil noise. One year later, theBundesanstalt für Arbeitsschutz undArbeitsmedizin (German FederalInstitute of Occupational Health)was commissioned to carry outthe most extensive research projectto date on "Noise in educationalestablishments". Observations frommore than 570 lessons showedan average classroom SPL (soundpressure level) of approximately65 dB(A). Levels that are thishigh mean that communicationcan be extremely difficult or evenimpossible.Answers (%)50403020ISF study, 1999: 80%of teachers complainabout the noise madeby pupils100do not agreeat all2tend not toagreeagreeslightlyOf course, the sound pressure levelmeasured in the classroom doesnot only consist of unwanted noise,since the teacher's voice and anecessary contribution of pupilvoices are also involved. Thus,overall classroom noise is generatedby the two-way teaching processas well as by other factors. Evenif this overall level were generatedexclusively by the teacher, thiswould mean - at the very least - thathe or she would have to speak ina raised voice throughout the entirelesson.The question of noise in schoolsis therefore extremely complex.How, for instance, does the generalnoise level in the classroom affectthe communication processesthat take place there? How it ispossible to differentiate betweendisturbing noise on the one handand useful noise (sound) on theother hand, when carrying out ascientific teaching analysis? Howdo SPL and poor understandingof communication affect pupilperformance and/or teachers' workstress? And, not least, what areteachers really talking about whenthey complain about noise in theclassroom – the measurable SPLor, rather, the way in which theirteaching is disturbed?All these issues resulted in themost recent ISF study in 2005on the "Acoustic ergonomics ofschools". Based on 175 lessons,the first stage involved researchingthe effects of different teachingmethods (direct teaching vs.student-centred teaching) on thebasic* and working** SPL inthe classroom. The second stageinvolved an investigation intohow changing room acoustics(reverberation time and speechintelligibility) affects this level foreach respective teaching method.It was possible not only to analyseaverage values for lessons butalso to gain insight into actualteaching phases that showed clear,pedagogical characteristics.totally agree*The Basic SPL: the general basic noise level in a fully occupied class over a defined time period.** The Working SPL: the noise level parameter describing a working situation.
The third stage then addressed hownoise, in terms of natural, workingsounds, affects teachers duringlessons. How do room acousticsaffect teachers' measurablephysiological stress in relation toactual teaching events?These kinds of ergonomicquestions, linked with actualeducational trends, may besurprising at first glance. However,they give an interesting insight intothe concept of noise in schools,its causes and effects, and intoother acoustic factors such asreverberation time and speechintelligibility.2. Teaching past andpresent - schooling reflectedin educational trendsThe education system in mostindustrialised countries is changingfaster than ever before, not justsince recent OECD-Reports1).The organisation of schooling ingeneral, and teaching methods inparticular, have changed a lot inrecent years.Is noise in schools a newproblem, one that did not existpreviously? This question is certainlyjustified, since complaints byteachers about noise do not occurin the literature from the beginningof the 1900s. The "modern","student-centred" and "non teachercentred" teaching methods (e. g.partner, group or project work)that are promoted by educationalexperts do certainly produce totallydifferent communication scenarios1) OECD (Organisation for Economic Co-operation and Development)/PISA (Programme for International StudentAssessment, Learning for Tomorrow's World, First Results from PISA 2003, OECD Publishing, Dec 2004, 478 p,ISBN: 9264007245. (Available in English, German, French, Portuguese and Spanish)OECD/Centre for Educational Research and Innovation (CERI), Schooling for Tomorrow: Think Scenarios, RethinkEducation, OECD Publishing, April 2006, 200 p, ISBN: 926402364X (Available in English and French)School with predominantly student-centred teaching method.School with predominantly direct teaching method.3
in the classroom in comparisonwith those produced by traditional,direct teaching. The image of theteacher as a distributor of material,a channel of knowledge, is fading.Pupils now have to independentlyinvestigate, weigh up, discussand acquire the knowledge andskills to solve the problems theyare presented with. Modernteaching relies much more onshared learning, and deliberatelypermits several people to talk inthe classroom at the same time.Even in a disciplined discussionenvironment, however, higher noiselevels than before occur, whenteachers used to lecture the classas a whole. This is particularly thecase when the teacher exercises ahigh level of discipline.Nowadays we tend to find amix of direct and student-centredteaching styles in the classroom (keyphrase "frontal teaching discussion").4The methods chosen are generallydependent on the personalpreferences of the teaching staffand on the prevailing teachingstyle at the school in question.The layout of the classroom andthe arrangement of the desks aresometimes relevant, since theseindicate the teaching methodsthat are used to determine whathappens in the classroom.Shortsighted analyses, whichhave attributed the much highernoise levels in recent decadesexclusively to social or educationaltrends, fall far short of the truth.Even early investigations provedthe relationship between a room'sacoustic working environment,the quality of communication andthe development of noise in theclassroom. It is therefore importantto ask: What are the determiningfactors for teaching in respect ofmodern, educational methods?The presence of technology was only unfamiliar for a short time. After just a fewhours, children saw the measuring instruments and loudspeakers as just anotherpart of normal classroom equipment.3. The peculiarities of noisein schoolsWhen discussing noise in relationto education and schools, its qualityand quantity are very differentfrom that of the noise occurring incommercial workplaces, be it anindustrial or an office environment.While the noise produced bymachinery is generally felt to benoise interference, the noise levelin educational environments shouldbe regarded as a useful signalwith a widely varying degree ofinterference factor. Its differentiationand evaluation depend on theteaching method being used inthe case in question. For example,while text being read out in avoice with a speech volume ofaround 65 dB(A) must be rated asa useful or wanted signal, generalpupil murmur of around 55 dB(A)during a quiet working period mightbe rated as noise interference. Astraightforward increase in the noiselevel in a classroom, without takingthe actual teaching situation intoconsideration, is only a small partof the noise in schools concept.A first, decisive criterion forappraising noise in schoolsis the ratio of “useful signal”to “interference signal” in theclassroom, taking into account thecommunication processes in thelesson. For an adult, the usefulsignal must generally be around9 dB higher than the interferencesignal if error-free speech
intelligibility is to be achieved.Since an adult voice is designed fora normal speech volume of around50 to 55 dB(A), this means thatthe noise interference level must beless than 40 dB(A). Even in quietwork periods, however, the SPL inschools seldom measured under 50dB(A), i.e. teachers usually have toraise their voices in order to passinformation on to the pupils. Inaddition, specialist literature pointsout that primary-school childrenneed to specifically learn how tolisten and understand before theycan develop their as yet untrainedacoustic memory. Young hearerstherefore need a useful signal levelthat is about 15 dB louder thanthe ambient noise interference. Anadded difficulty is the fact that thenoise interference in a classroom isrelatively evenly distributed, whilethe teacher's voice is transmittedfrom only one point and –depending on the size of the roomand the position of the teacher- may need to travel over a distanceof up to 6 m to reach pupils sittingat the back. If the basic noise isunchanged, this involves eithera distinct additional strain on theteacher's voice, leading to longterm health consequences, or aninterrupted flow of information topupils sitting further away, resultingin negative effects on their learning.There is another aspect toconsider in relation to modern,student-centred teaching methods. Ifthere are several groups speakingin the room at the same time, thesignal from one group becomesnoise interference for the othergroups. This results in a negativechain reaction. The other groupsIn more than 570 lessons, as well as the SPL being measured, the activities inthe classroom such as teaching methods or proportion of speech were recordedevery second.will compensate for the poorerspeech intelligibility in their groupsby raising their voices, which inturn increases the noise interferencelevel for the others, and so on.The noise level in the classroomtherefore gradually increases evenif the number of people actuallycommunicating remains the same.This is known in acoustic circles asthe Lombard effect.5
4. "Acoustic Ergonomics" –noise in schools andteachers' healthRoom acoustics are particularlysignificant with regard to modernteaching. For instance, shortreverberation times result in aprecise speech signal (especiallyin respect of consonants), andpeople can communicate with alower signal-to-noise ratio. The studyAcoustic Ergonomics in Schools(2005) showed that the build-upof noise is considerably less, ordoes not occur at all, in classroomsthat have good acoustics. On thecontrary, under optimum conditionsthe noise level measured duringstudent-centred teaching phaseswas even lower than during directteaching.Overall, the basic SPL inclassrooms with reverberation timesof less than 0.5 seconds were 8dB lower than in classrooms withreverberation times of between 0.6and 0.8 seconds.Share of "quiet" teaching phases (overall) in classrooms withgood/poor acoustics.Share of time (%)80706050403020100Reverberation time 0.5 sec.Reverberation time 0.5 sec.Under better acoustic conditions, the proportion of "quiet" teaching units wasmore than 80% compared to approximately 67% under poorer conditions (inrelation to the average speech volume of an adult - approx. 62 dB(A) - takenas normal teaching speech).6
Pupil-centred teaching phases are frequently quieter undergood acoustic conditions.Share of time (%)The rise of the basic SPL over the morning is much less inrooms with short reverberation times.LA95 [dB(A)]807070606550604030552050100Reverberation time 0.5 sec.Reverberation time 0.5 sec.Even more obvious is the change in classroom conditions during student-centredteaching phases. In this case the proportion of quiet time units doubles! Thisclearly indicates an absence of the Lombard effect during partner, group orproject work. The difference in levels between rooms with good acoustics andthose with poor acoustics while these teaching methods were used was morethan 13 dB!4540353012345LessonsAn additional, important aspect was revealed by this comparison of teachingsituations. The normal increase in the basic noise level over the course of theschool day did not occur in the classrooms with short reverberation times ( 0.5seconds). This has a significant effect on the teaching process and provides aninitial indication of the physiological reactions that take place as a result of theacoustic working environment.7
After acoustic refurbishment, the teacher works with arelaxed heart rate for more than 80% of the time comparedto just 60% before refurbishment.Share of time (%)1009080706050Reverberation time 0.5 sec.Reverberation time 0.5 sec.The positive effects of good room acoustics also reduce the teacher's stress level.After an acoustic refurbishment, the same teacher was subject to comparativelylittle work stress for a much greater part of the lesson. Further investigations alsoshowed that the teacher was less sensitive to the stress-inducing noise, withwork thus becoming much more relaxed. It is undoubtedly true that there is anergonomic dimension to the acoustic design of classrooms. It directly affects thelevels of work stress, activation and fatigue of the people who teach (and learn)in these premises.85. Consequences andoutlookWith a change in educationalapproaches, a steady increase instudent-centred teaching methodsand a corresponding reduction indirect teaching, it may be necessaryto re-evaluate school buildings thathave functioned well for manyyears. New teaching methodsplace new demands on the basicergonomic conditions.It would be absurd to claimthat teachers themselves haveno influence on noise in theirclassrooms. They do, of course– and it is important that theyexert this influence. This issue isaddressed in depth in the researchreport of the study "Noise ineducational establishments" (2004).This study also showed the levelreductions that can be expectedafter fairly immediate intervention byindividual teachers: approximately2 dB. At the same time, however,in rooms with resembling acousticconditions and a comparable pupilsocial structure, there was evidenceof similar differences (5 to 6 dB)in the noise levels of differentschools. The relationships wereeasily identifiable. Only the schoolswhere the staff followed a common,accepted educational concept werereally quiet. In schools where thesame rules apply in all classrooms,during all lessons and in all thedifferent areas of the school, andwhere the children can expect thesame teacher reaction if they do notcomply with those rules, the noiselevels measured over a long periodwere lower. The recipe is thereforeas simple as it is effective. The onlyrequirement is that staff work as ateam and are consistent.The school organisation andthe personal contributions ofindividual teachers are essentialfactors in effectively reducingnoise in schools. The ergonomicconditions provide the necessaryfoundation for the teaching activitiesof the school day. Neither of thetwo aspects can be replacednor offset by the other. They aremutually interdependent and needto interact if the teaching processin context of modern pedagogicalcommunication is to functionproperly.
The proud team of "scientific staff" after successfully measuring the acoustics of their classroom.9
Classroom solutionRecommendation for normal sized classrooms(area: 100m², volume: 200m³, length: 9m)1.1 - Classroom SolutionAcoustic ceiling of sound absorptionclass A (Ecophon Master)Wall absorber from 0.8 to 2.0 metresabove the floor (Ecophon Wall Panel)1.1 Classroom solutionReflector over the teacher's deskarea if enhanced speech comfort isneeded (Ecophon Master/gamma)1.2Classroom1.2 - ClassroomSolution solution with lowwith low frequencyabsorberabsorberfrequency10Additional wall absorber from 0.8 to 2.0above the floor if there is a risk for flutterecho or if increased sound level reductionis needed (Ecophon Wall Panel)Low frequency absorber(Ecophon Master Extra Bass)
GlossaryAcousticsThe study of sound. In everyday language also refers to how sound isperceived in particular premises.Reverberation time, (T or RT)The time it takes for the sound pressure level to fall by 60 dB after thesound has been turned off. Measuring the reverberation time allows usto calculate the total sound absorption. The reverberation time variesaccording to the frequency.Sound pressure level (dB)The variations caused by sound waves in air are called sound pressure.The lowest sound pressure level which can be heard is 0 dB, known asthe hearing threshold. The highest level which can be tolerated is calledthe pain threshold and is around 120 dB.Speech intelligibilitySpeech intelligibility is directly dependent on the level of backgroundnoise, reverberation time and the shape of the room. Different methodsare used to evaluate speech intelligibility, the most common ones areRASTI, STI and %ALcons.Lombard effectThe Lombard effect is the tendency to increase one's vocal intensity innoise. Ecophon Group 2006Idea and layout: Saint-Gobain Ecophon AB, Printer: Skånetryck AB, Photo: Saint-Gobain Ecophon GmbH, Illustrations: Condesign Infocom AB, Dr Gerhard Tiesler and Saint-Gobain Ecophon GmbH11
Complaints about noise pollution in educational premises were thereason to cast a light on causes and consequences of “school noise”.This interdisciplinary study investigated various kinds of teaching/learning styles and sound pressure levels in the classroom, andmoreover, how improved room acoustic conditions affect sound levelstogether with teachers' workload and fatigue.This publication is a complement to the book “Don't limit your senses” Sound and the Learning Environment,Saint-Gobain Ecophon, ISBN 91-974193-2-X published in 2002.06.11 5000, Art no: 929050Saint-Gobain Ecophon AB, Box 500, S-260 61 Hyllinge, Sweden, phone 46 42 17 99 00, fax 46 42 22 59 29,e-mail: ecophon.export@ecophon.se, www.ecophon-international.com
of the 1900s. The "modern", "student-centred" and "non teacher-centred" teaching methods (e. g. partner, group or project work) that are promoted by educational experts do certainly produce totally different communication scenarios School with predom
Ecophon Focus DS aaa-400/500 Ecophon Master DS aaa-400/500 Ecophon Focus DG aaa-400/500 Ecophon Access A aaa-400/500/600 Parafon Exclusive E24 Parafon Nordic E24 Ecophon Focus E Danoline 600 aaa-400/500/600 Dampha H 23 SAS 150 H 36 * aaa max 315 for 500x500 aaa max 400 for 600x600 Suspended
Ecophon Focus (sin incluir canto F ni Sistemas adicionales) 500 m² Desde canto A a SQ Ecophon Master (sin incluir canto F, Master Matrix ni Rigid) 6 /m² 500 m² Desde canto A a SQ 8 /m² * Ecophon Akusto One Min. 1 Caja Canto disponible en blanco y gris 20 % Ecophon Solo (sin inc
Arcs Wide L-Acoustics LA4X L-Acoustics SB18m Rental List 2018 8 Lautsprecher, Verstärker und Lautsprecherrigging L-Acoustics Coax L-Acoustics 12XT 1x12" /1x3" Coaxial 90 Radial 42,00 L-Acoustics 12XT ETR 12-2 Bügel für 12XT 12,00 L-Acoustics Arcs L-Acoustics Focus 1x12"/1x3" 90 x 15 49,00 .
L.Acoustics LA8 L.Acoustics Arcs Wide/ Focus L.Acoustics Arcs Wide L.Acoustics SB18i L.Acoustics LA4 L.Acoustics 12XT L.Acoustics 115XT Hiq Midas M32 Midas DL16 TC D-Two 6 Shure SM 58 1 Shure BETA 58A 2 Shure BETA 87A 2 Shure HF SLXD/SM58 6 Shure SM 57 1 Shure Béta 57 A 1 Shure BETA 52A 1 Shure BETA 91 2 Shure SM 81LC 2 Sennheiser E 906 4 .
L.Acoustics LA8 L.Acoustics Arcs Wide/ Focus L.Acoustics Arcs Wide L.Acoustics SB18i L.Acoustics LA4 L.Acoustics 12XT L.Acoustics 115XT Hiq Midas M32 Midas DL16 Yamaha CDS 300 BK VOX AC 30 C2 MARSHALL DSL 40C ORANGE THUNDER 30W 2 canaux ORANGE 4x12 Pan coupé 240W DAVID EDEN WTX264 baffle D210T AMPEG SVT VR 300W AMPEG SVT810E 800W
Ecophon Focus Fixiform E A T24 1200x600x20 Focus E Ecophon Focus Flexiform A A T24 1200x600x30 1600x600x30, 2000x600x30, 2400x600x30 Focus A Ecophon Focus Frieze A T24 2400x600x20 Focus A, Focus Ds, Focus Dg, Focus E Ecophon Focus Wing A T24 1200x200x5
Ecophon D Rockfon D-XL Ecophon Focus DG Rockfon E10 24 Ecophon - E / T24 Rockfon E10 15 Ecophon - E / T15 Danotile Markant V H R V H R V H R V H R V H R V H R Grille box/plenum boxes Product 125 160 200 250 315 Size Design See Comfort and Design 125 160 200 250
L'Acoustics ARCS Wide L'Acoustics X12 center L'Acoustics X12 delay L'Acoustics 5XT frontfill 2 2 2 2 1 1 1 1 1 4x FOH amps L'Acoustics LA12X 1 L'Acoustics LA4X 1 Active set Electrovoice ELX112P Top 2 Electrovoice ELX118 Sub 2 Amps monitors Powersoft M50 Q - monitors (4 channels) 1 Monitors Martin Audio LE 1200 4 .
