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(1)

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Rumsakustik

Erling Nilsson, Akustiker ECOPHON Saint-Gobain

(2)

Community school no 15, Gdynia, Poland. Architect: Adam Drochomiercki. Photo: Szymon Polanski.

System: Ecophon Master A/alpha

(3)

Production unit Distribution center

European supply chain

Forssa

A sound effect on people Our mission and vision The Ecophon Story Company facts Part of Saint-Gobain Care for environment Our way to the market Products and systems References Ending

Market segments Production and logistics

Næstved

Hyllinge

Gliwice Chalon

(4)

Saint-Gobain

• One of the world’s 100 leading industry groups

• Focusing on habitat and construction

• Established in 1665

• Present in 64 countries

• 190 000 employees

• ~ €40 billion in sales

Spegelsalen i Versailles

(5)

Four market segments

• Long experience of how sound affects people

• Specialised knowledge about segment specific activities

• Systems developed for specific needs

Education Modern Office Healthcare Clean Industry

(6)

Benefits of good acoustics

• Increased wellbeing and satisfaction

• Less tiredness

• Easier to concentrate

• Fewer errors

• Less stress hormones

• Easier to communicate

• More positive energy

• Increased creativity

(7)

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Room Acoustic design in practise

(8)

Innehåll

• Något om Ecophon

• Rumsakustik i praktiken

• Betydelsen av god akustik

• Rumsakustik och ljudabsorption

• “Activity based acoustic design”

• Rumsakustiska mått

• Effekt av akustikreglering I klassrum

• Öppna kontorslandskap

• Några exempel på akustikreglering

(9)

Schools:

Positive effects of a good sound environment in educational premises include:

• Reduced vocal strain and voice disorders for teachers

• Improved concentration

• Reduced tiredness, fatigue and stress levels

• Easier to hear and be heard with improved speech clarity

• Optimised environment for multi-communicational activities such as group work

• Improved student behaviour and reduced burden on school and classroom management

(10)

Healthcare:

Better sound environment contributes to:

• Lowering of blood pressure

• Improving quality of sleep

• Reducing intake of pain medication

• Reducing the number of re-admissions

• Improving the wellbeing of staff and increasing perceived performance

(11)

Open-plan offices:

• In a modern flexible OPO, the creation of a functional work station is a complex process in which acoustic planning is only one part of a series of considerations having to be addressed. The open-plan office should support both communication and concentrated work. Thus, for an OPO to be an efficient and comfortable

place of work there are several other requirements than acoustic treatment that have to be fulfilled.

(12)

Public health experts agree that environmental risks constitute 24% of the burden

of disease. Widespread exposure to environmental noise from road, rail, airports

and industrial sites contributes to this burden. One in three individuals is annoyed

during the daytime and one in five has disturbed sleep at night because of traffic

noise. Epidemiological evidence indicates that those chronically exposed to high levels

of environmental noise have an increased risk of cardiovascular diseases such as

myocardial infarction. Thus, noise pollution is considered not only an environmental

nuisance but also a threat to public health.

WHO report

(13)

Sabine formula

where

T=the reverberation time (s) V=the room volume (m

3

)

A=the total equivalent absorption area (m

2

sabin)

where

 

 

 

A

T 0 . 16 V 

 

 

T A 0 . 16 V

or

The equivalent absorption area A for a surface with area S m

2

is equal to α x S where α is the absorption coefficient for the

surface

(14)

Acoustic design with Sabine formula

 A(before treatment)=0,161xV/T= 0,161x200/2,5=12,9 m

2

sabin

 A(needed to fulfil 0,40 s)= 0,161xV/T=0,161x200/0,40=80,5 m

2

sabin

 A( to be added to fulfil 0,40 s)=A(needed)-A(before)=80,5-12,9=67,6 m

2

sabin

Example: The reverberation time in a room with a volume of 200 m

3

is 2,5 s at 1000 Hz.

Target value for the reverberation time is 0,40 s at 1000 Hz

If e.g. the absorption coefficient for a ceiling absorber is 0,90 at 1000 Hz

we will need S= A/α=67,6/0,90=75 m

2

(15)

Sabine formula: How it works in theory

Absorption coefficients (500 Hz):

Walls=0,15 Ceiling=0,80 Floor=0,10

(16)

Absorption data from EN 12354-6

(17)

Absorption data from EN 12354-6

(18)

Sabine formula: How it works in theory

Absorption coefficients (500 Hz):

Walls=0,15 Ceiling=0,80 Floor=0,10

A=∑αi x Si = 0,10x6x7,5+2x0,15x7,5x2,5+2x0,15x6x2,5+0,80x6x7,5=51 m2 sabin T60=0,161x(V/A)=0,161x112,5/51≈0,36 s

(19)

Not a typical classroom

(20)

Definition: Reverberation time

Sound pressure level, dB

Time, seconds 60 dB

T

60

(21)

Reverberation decay in rooms with suspended absorbent ceiling

T

20

Increased diffusivity

(22)

Typical classroom

(23)

Effect of furniture

absorption

scattering

(24)

No boxes

Boxes on the wall Sabine

Scattering – why is it important?

Glass wool

(25)

Reflection from a surface

Specular reflection

–Angle of reflection equals angle of incidence

θ θ

Incident sound energy, Iinc

Reflected sound energy, Irefl

Absorption coefficient:

(26)

Reflection from a surface

Specular reflection

–Angle of reflection equals angle of incidence

Diffuse reflection

–Scattered in many

directions

(27)

Reflection from a surface

Scattering coefficient, s

• Fraction of energy which is scattered

• Always between 0 and 1

(28)

Absorption and scattering

absorbed specularly reflected diffusely reflected

(29)

Simulation of sound fields

(30)

Lambert’s law:

𝐼 𝜃 = 𝐼 0 cos (𝜃)

Acoustical radiosity The image source method

PARISM – simulation tool for ordinary rooms

Industrial PhD project together with DTU

Forskning

(31)

Auralisation with loudspeaker array using higher order ambisonics

Forskning

(32)

Activity based acoustic design – a method to approach room acoustic design

Several room acoustic parameters

are needed for a relevant

characterization of room acoustic

conditions

(33)

Assessment of sound in rooms

Sound source

Physical region Physiological and

psychological

region Room

Sensation

Sound strength

Clarity

Sharpness

Preference

(34)

Assessment of sound in rooms

(35)

Room types

Reverberant room (Sabine room)

Reverberation time

Open-plan spaces

Spatial decay

Room with absorbent ceiling

Speech clarity Sound strength Reverberation time

(36)

Room acoustic quality aspects

• Reverberation

• Speech clarity

• Auditory strength

• Spatial decay

(37)

Efterklang

• Relaterar till hur snabbt ljudenergin försvinner i ett rum

Lång efterklang Kort efterklang

(38)

Parameters for performance spaces ISO 3382-1

Subjective quality Objective measure

Clarity Clarity index (C80)

Reverberance Early decay time (EDT))

Intimacy Sound strength (level)

Source broadening Early lateral fraction and strength

Loudness Sound strength and source-

receiver distance

M. Barron, The development of concert hall design – A 111 year experience, Proce edings of the Institute of Acoustics, Vol. 28. Pt. 1. 2006

(39)

ISO 3382-2: Reverberation time in ordinary rooms

ISO 3382-3: Open plan offices (T

20

not included)

Schools

Offices

Hospitals

(40)

Room acoustic quality aspects and parameters

Ordinary rooms:

• Reverberation: T20 (s), ISO 3382-2

• Speech clarity: C50 (dB), ISO 3382-1

• Auditory strength: G (dB), ISO 3382-1

Open plan spaces:

• Spatial decay: according to ISO 3382-3

(41)

Useful reflections

Detrimental reflections

end) ) Energy(50

50ms) Energy(0

log(

10 C

50

 

 , dB

Definition of room acoustic measures: Speech Clarity C

50

(dB)

(42)

Room acoustic measures: Sound strength G (dB)

G = Lp

Room

– Lp

10m

=Lp – Lw + 31 dB (omni-directional sound source)

10 m

G=70 dB - 60 dB= 10 dB

(43)

Sound Power Source

Sound strength G (dB) G=Lp-LW+31 (dB)

(44)

Subjective listener aspect

Room acoustic quantity

Just noticeable difference

Subjective level of sound

Sound Strength G in dB 1 dB

Perceived reverberance

Reverberation time T20 in seconds

5%

Perceived clarity of sound

Speech Clarity C50 in dB 1 dB

Just noticeable difference of room acoustic quantities

according to ISO 3382-1

(45)

Microphone Loudspeaker

Reverberation time, T

20

Speech clarity, C

50

Sound

Strength, G Impulse response

time, s

Room acoustic measurements

(46)

Small meeting rooms

Two similar rooms with different ceiling treatment.

Room 1: Ceiling absorber αw = 1.0 Room 2: Ceiling absorber αw = 0.1 Floor area = 12 m2

Height = 2.7 m

(47)

Semantic differential questionnaires

Extremely Very Fairly Partly Fairly Very Extremely

Distinct Indistinct

Pleasant Unpleasant

Dry Reverberant

Best possible listening environment

Worst possible listening environment Best possible

speaking environmen

Worst possible speaking environmen

X

(48)

Semantic differential questionnaires

Extremely Very Fairly Partly Fairly Very Extremely

Distinct Indistinct

Pleasant Unpleasant

Dry Reverberant

Best possible listening environment

Worst possible listening environment Best possible

speaking environmen

Worst possible speaking environmen

X

(49)

Listening test

(50)

Listening test

(51)

Listening test

(52)

Listening test

(53)

Listening test

(54)

Measurement results

(55)

Measurement results, with wall panels

(56)

Ecophon recommendation: Schools

Criteria Parameter* Target values Speech clarity C50 (dB) 6 – 8 dB

Sound strength

G (dB) 15 – 17 dB

Reverberation T20 (s) 0,40 – 0,50 s

* Average 125 to 4000 Hz

(57)

The effect of different acoustical treatment

Volume= 150 m3, Floor area=55 m2, ceiling height=2,70 m

• No ceiling treatment, no furniture

• Ceiling treatment, no furniture

• Ceiling treatment, furniture

• Wall panels

• Extra low frequency

absorption

(58)

Classroom in different configurations

Without furniture and ceiling Without furniture, with ceiling

With furniture and ceiling With furniture, ceiling and wall panels

(59)

Measurement positions

Ceiling height: 2,70 m

Volume: 150 m

3

(60)

Without furniture and ceiling

0,00 0,50 1,00 1,50 2,00 2,50 3,00 3,50 4,00 4,50

125 250 500 1000 2000 4000

Reverberation time (s)

Frequency (Hz)

Reverberation time T20(s)

-9,00 -7,00 -5,00 -3,00 -1,00 1,00 3,00 5,00

125 250 500 1000 2000 4000

Speech Clarity C50 dB

Frequency Hz

Speech Clarity C50 dB

0,00 5,00 10,00 15,00 20,00 25,00 30,00

125 250 500 1000 2000 4000

Sound strength G dB

Frequency Hz

Sound Strength G dB

Average absorption coefficient of the room surfaces is 0,05

(61)

Practical absorption coefficient of Gedina A

0 0,2 0,4 0,6 0,8 1 1,2

125 250 500 1000 2000 4000

Practical absorption coefficient

Frequency Hz

Gedina A

(62)

Without furniture with ceiling

0,00 0,50 1,00 1,50 2,00 2,50 3,00 3,50 4,00 4,50

125 250 500 1000 2000 4000

Reverberation time (s)

Frequency (Hz)

Reverberation time T20(s)

-9,00 -7,00 -5,00 -3,00 -1,00 1,00 3,00 5,00

125 250 500 1000 2000 4000

Speech Clarity C50 dB

Frequency Hz

Speech Clarity C50 dB

0,00 5,00 10,00 15,00 20,00 25,00 30,00

125 250 500 1000 2000 4000

Sound strength G dB

Frequency Hz

Sound Strength G dB

(63)

Without furniture with ceiling

-9,00 -7,00 -5,00 -3,00 -1,00 1,00 3,00 5,00

125 250 500 1000 2000 4000

Speech Clarity C50 dB

Frequency Hz

Speech Clarity C50 dB

0,00 0,50 1,00 1,50 2,00 2,50 3,00 3,50 4,00 4,50

125 250 500 1000 2000 4000

Reverberation time (s)

Frequency (Hz)

Reverberation time T20(s)

Calculation according Sabine formula

0,00 5,00 10,00 15,00 20,00 25,00 30,00

125 250 500 1000 2000 4000

Sound strength G dB

Frequency Hz

Sound Strength G dB

(64)

Furniture absorption

T

0

empty room T

furn

furnished room

(65)

With furniture and ceiling

0 0,2 0,4 0,6 0,8 1 1,2 1,4 1,6 1,8 2

125 250 500 1000 2000 4000

Reverberation time (s)

Frequency (Hz)

Reverberation time T20(s)

-2 -1 0 1 2 3 4 5

125 250 500 1000 2000 4000

Speech Clarity C50 dB

Frequency Hz

Speech Clarity C50 dB

0 2 4 6 8 10 12 14 16 18

125 250 500 1000 2000 4000

Sound strength G dB

Frequency Hz

Sound Strength G dB

(66)

With furniture and ceiling

-2 -1 0 1 2 3 4 5

125 250 500 1000 2000 4000

Speech Clarity C50 dB

Frequency Hz

Speech Clarity C50 dB

0 2 4 6 8 10 12 14 16 18

125 250 500 1000 2000 4000

Sound strength G dB

Frequency Hz

Sound Strength G dB

0 0,2 0,4 0,6 0,8 1 1,2 1,4 1,6 1,8 2

125 250 500 1000 2000 4000

Reverberation time (s)

Frequency (Hz)

Reverberation time T20(s)

(67)

The effect of wall panels

0,00 0,20 0,40 0,60 0,80 1,00 1,20

125 250 500 1000 2000 4000

Reverberation time (s)

Frequency Hz

Reverberation time T20(s)

0 1 2 3 4 5 6 7 8 9

125 250 500 1000 2000 4000

Speech Clarity C50 dB

Frequency Hz

Speech Clarity C50 dB

0 2 4 6 8 10 12 14 16

125 250 500 1000 2000 4000

Sound Strength G dB

Frequency Hz

Sound Strength G dB

(68)

Ecophon Gedina A with Extra Bass

(69)

The effect of extra low frequency absorption

With 50% Ecophon Extra Bass

0,00 0,20 0,40 0,60 0,80 1,00 1,20

125 250 500 1000 2000 4000

Reverberation time (s)

Frequency Hz

Reverberation time T20(s)

0 1 2 3 4 5 6

125 250 500 1000 2000 4000

Speech Clarity C50 dB

Frequency Hz

Speech Clarity C50 dB

0 2 4 6 8 10 12 14 16

125 250 500 1000 2000 4000

Sound Strength G dB

Frequency Hz

Sound Strength G dB

(70)

Wall panels and Ecophon Extra Bass

With 50% Ecophon Extra Bass

0,00 0,20 0,40 0,60 0,80 1,00 1,20

125 250 500 1000 2000 4000

Reverberation time (s)

Frequency Hz

Reverberation time T20(s)

0 1 2 3 4 5 6 7 8 9

125 250 500 1000 2000 4000

Speech Clarity C50 dB

Frequency Hz

Speech Clarity C50 dB

0 2 4 6 8 10 12 14 16

125 250 500 1000 2000 4000

Sound Strength G dB

Frequency Hz

Sound Strength G dB

References

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