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Early Design Criteria for Multipurpose Cultural Houses

by Anders Buen

Paper version:

http://www.akutek.info/Papers/AB_EarlyDesignCriteriaSmallHalls.pdf

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Title Index Stage Acoustics

Concert Hall Acoustics

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201

0Early design criteria for small multipurpose cultural houses

Berg

en 1

0-12

. mB

NA

M B

Early design criteria for multipurpose cultural houses

A t ti ti l t d f d h ll d tA statistical study of measured hall dataAnders Buen, Brekke & Strand akustikk as

Anders Buen, 10-12. mai 2010

mai

201

0Early design criteria for small multipurpose cultural houses

Sources - Reference dataBe

rgen

10-

12. m

BN

AM

B

18 chamber music halls

85 concert halls

Anders Buen, 10-12. mai 2010

mai

201

0Early design criteria for small multipurpose cultural houses

Sources - recommendationsBe

rgen

10-

12. m

Sources recommendations• NBI Handbook 20 ”Room acoustic projecting”

BN

AM

B NBI Handbook 20 Room acoustic projecting• Recommendations from the Council for Musical

Organizations in Norway (CMON)Organizations in Norway (CMON)

Anders Buen, 10-12. mai 2010

mai

201

0Early design criteria for small multipurpose cultural houses

Measurement positions from A. C. GadeBe

rgen

10-

12. m

pSources (Loudspeaker)

BN

AM

B

( p )

Receivers (Microphone)

A receiver also in the sound engineers position

Anders Buen, 10-12. mai 2010

We use hall averages in this study

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201

0Early design criteria for small multipurpose cultural houses

Measured hallsBe

rgen

10-

12. m

Measured hallsB

NA

M B

• 11 multipurpose• 5 rehearsal- and concert halls• 3 theatres incl a large ”black box”• 3 theatres incl a large black box• = 19 halls - 34 data points

Anders Buen, 10-12. mai 2010

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201

0Early design criteria for small multipurpose cultural houses

Some definitionsBe

rgen

10-

12. m

Some definitionsB

NA

M B • V = hall and scene volume [m3]

• N = Number of seats• N = Number of seats• V/N = Volume per seat [m3]• RTM = Mid frequency reverberation time [s]

G L d h d d• G = Loudness, the measured sound pressure level in relation to the SPLfree field at 10m [dB]free field [ ]

• AM = Calculated absorption area [m2 Sabine]

Anders Buen, 10-12. mai 2010

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201

0Early design criteria for small multipurpose cultural houses

Some hall data averagesBe

rgen

10-

12. m

Some hall data averagesT pe hall V [m3] N V/N RT [s] GM AM [m2

BN

AM

B Type hall V [m3] N [m3] RTM [s] M[dB]

M [Sabine]

Chamber 4100 530 8 1.8 11 400

“Our” 4900 360 14 1.4 7 600

Concert 20500 2200 10 2.2 4 1500

• Our halls are: – less reverberant, in spite of larger volumes per seat and– moderately loud y

Anders Buen, 10-12. mai 2010

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201

0Early design criteria for small multipurpose cultural houses

Measured G versus absorption area, ABe

rgen

10-

12. m

p ,16

BN

AM

B

y = -4.50Ln(x) + 36.04R2 = 0.85

12

14All 138 halls

8

10

[dB]

4

6

easu

red

GM

0

2

Me Our halls

-4

-20 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

Calculated A [m2 Sabine]

Anders Buen, 10-12. mai 2010

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201

0Early design criteria for small multipurpose cultural houses

Measured versus expected GBe

rgen

10-

12. m

Measured versus expected G 18

BN

AM

B

14

16 All 138 halls

8

10

12

[dB

]

Expected G (diffuse field)

4

6

8

asur

ed G

M [

Our halls

0

2

0 2 4 6 8 10 12 14 16 18

Mea

-4

-2 0 2 4 6 8 10 12 14 16 18

Expected G = 10log(T/V) + 45 dB

Anders Buen, 10-12. mai 2010

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0Early design criteria for small multipurpose cultural houses

Measured Strength G and volumeBe

rgen

10-

12. m

Measured Strength G and volume16

BN

AM

B

14

Chamber halls

10

12

M [d

B]

Chamber halls

6

8

treng

th G

M

4

6

St

Our halls

0

2

Anders Buen, 10-12. mai 2010

1000 10000Volume of hall and stage [m3]

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201

0Early design criteria for small multipurpose cultural houses

Meas RT and CMONs (Musikkrådets) requirementsBe

rgen

10-

12. m

( ) q

2.4

2.6

BN

AM

B

1 8

2.0

2.2Chamber halls

1.4

1.6

1.8

c M

, [s]

Loud instruments

Our halls

0.8

1.0

1.2

RT

Uno

cc Loud instruments

0.4

0.6

0.0

0.2

100 1000 10000Hall and scene volume [m3]

Anders Buen, 10-12. mai 2010

Hall and scene volume [m ]

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0Early design criteria for small multipurpose cultural houses

NBI 20 and CMON (Musikkrådet) RT requirementsBe

rgen

10-

12. m

NBI 20 and CMON (Musikkrådet) RT requirementsB

NA

M B

2 83.03.23.4

2 02.22.42.62.8

]

1.41.61.82.0

RT

Occ

M, [

s]

0.60.81.01.2

Beranek/Hidaka occupiedBeranek/Hidaka occupied

O i d h llO i d h ll

0.00.20.4

100 1000 10000 100000

Our occupied hallsOur occupied halls

Anders Buen, 10-12. mai 2010

Hall and scene volume [m3]

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0Early design criteria for small multipurpose cultural houses

How much variation can be achieved?Be

rgen

10-

12. m

1400

BN

AM

B

1200

ne]

Halls with exposed stage textiles

800

1000

ea [m

2 Sab

i Halls with exposed stage textiles

600

orpt

ion

are

Our halls

200

400

Abs

o

Chamber music halls

01000 10000

Volume of hall + stage [m3]

Anders Buen, 10-12. mai 2010

g [ ]

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0Early design criteria for small multipurpose cultural houses

How much variation can be achieved?Be

rgen

10-

12. m

• Larger halls: A ≈ 800m2

BN

AM

B Larger halls: A ≈ 800m• 33% variation from 1,5s to 1 s:

Needed var abs: 500m2 Sabine = 1000m2 (α = 0 5)– Needed var abs: 500m Sabine = 1000m (α = 0.5)– Available surfaces: < 700m2

• Our best results: 250m2 and 340m2 Sabine

• Achieveable variation with stage textiles: – ΔRT = 0 2 - 0 3sΔRT 0,2 - 0,3s– ΔG = 1 -2 dB

Anders Buen, 10-12. mai 2010

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0Early design criteria for small multipurpose cultural houses

Unoccupied absorption per seat A/NBe

rgen

10-

12. m

Unoccupied absorption per seat A/N3.0

BN

AM

B

2.5

All concert and chamber halls Beranek and Hidaka

Norwegian cultural houses + 2 Am halls

2.0

er s

eat]

A/N=1,7 m2 Sabine

1.0

1.5

2 Sab

ine

pe

A/N=0,7 m2 Sabine

0.5A/N

[m2

No stage textilesSmall stage and Leather seats

0.0100 1000 10000

Number of seats

No stage textiles

Anders Buen, 10-12. mai 2010

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0Early design criteria for small multipurpose cultural houses

Volume per seat requirementBe

rgen

10-

12. m

Volume per seat requirementHalls with stage textiles: Halls with no stage textiles:

BN

AM

B

A/N = 1,7 m2 Sabine per seat A/N = 0,7 m2 Sabine per seat

RT ≥ 1.6s -> V/N > 21m3 per seatCeiling height: ≥ 15 m

RT ≥ 2s -> V/N > 11m3 per seat

Anders Buen, 10-12. mai 2010

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0Early design criteria for small multipurpose cultural houses

ConclusionsBe

rgen

10-

12. m

Conclusions

• The absorption in halls ith stage te tiles is abo t 1m2

BN

AM

B • The absorption in halls with stage textiles is about 1m2

Sabine per seat larger than in halls without

• These halls are less loud at the same volume

• Variations in RT of about 0,2-0,3 s is achieveable. If more is needed the stage textiles will need to bemore is needed, the stage textiles will need to be removed

• We need investigations into how well the multipurpose halls are functioning acoustically

Anders Buen, 10-12. mai 2010

g y