auditorium accoustical calculations.ppt

7/28/2019 Auditorium accoustical calculations.ppt

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OBJECTIVE

TO DESIGN A CONCERT HALL WHERE CONTEMPORARY MUSIC IS TO BE PERFORMED

GIVEN DATA-Volume of the room-15m*9m*5m = 675mcube

FOR CEILINGS,Ceiling should be reflective

Area of the ceiling=15*9=135msq.

If we are using on 46% of the ceiling then, area of acoustic tile is 63 sqm.

For 125Hz-63*.05=3.15

For 500Hz=63*.52=32.75

For 63Hz=63*.45=28.35

And we are using wood tongue and groove roof decking, then area is 72 sqm.

125Hz-72*.24=17.28

500Hz-72*.14=17.28

2000Hz-72*.13=9.35

Total for effective area of ceiling:-

125Hz-20.43500Hz-42.83

-

Reverberation time(Tr) required = 1.2-1.4

CALCULATIONS-

Sevines formula for calculating Tr = 0.161*v/A

Where Tr is reverberation time

The required area is A = .161*v/(1.2-1.4) = 77.62-90.56 msq.

A=A11+A22+A33+....... Where is absorption coefficient

Acoustics tiles

reflecting

AbsorbingAbsorbing

reflecting

Acoustics tiles

Wood tongue &

groove roof

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REAR SIDE WALL OF STAGE,Absorptive material should be used.

Total area=wall area-stage area

=(9*5)-(0.6*9)=45-5.4=39.6sq m.

Wall area=39.6-beam area=39.6-9.3=36.9

Plywood 3mm(1/8)panelling over 31.7mm airspace is used on the

wall,then area is 36.9

125Hz-36.9*.15=5.53

500Hz-36.9*.12=4.42

2000Hz-36.9*.08=2.952

Conc.(painted sealed) is used on the beam,area is 2.7 sqm.

125Hz-2.7*.01=.027

500Hz-2.7*.02=.054

2000Hz-2.7*.02=.054

Total effective area for rear side wall:-125Hz-5.557

500Hz-4.474

2000Hz-3.006

FRONT WALL OF STAGE,For the front wall of the stage:

Area of the total wall=9*5=45msq.

Beam area=9*0.3=2.7Door area=(1.5*2.1)*2=6.3

So area of the wall=45-2.7-6.3=36

If we are using pageboard over 25mmfibre glass on 50% of the wall:

125Hz-18*.08=1.44

500Hz-18*.99=16.2

2000Hz-18*.34=6.12

And rest 50% of the wall is used with drapery (1002/yd2,340g/m2,flat against wall)

125Hz-18*.04=.72

500Hz-18*.11= 1.98, 2000Hz-18*.3=5.4

Concrete painted sealed

Plywood

Page board

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drapery


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Two doors are used....if we use door metal material, then area of door is 3.15 each

125Hz=2(3.15*.1)=.63

500Hz=2(3.15*.05)=.314

2000Hz=2(3.15*.04)=.252

Conc.(painted sealed) is used:

125Hz-2.7*.01=.027

500Hz-2.7*.02=.0542000Hz-2.7*.02=.054

Total effective area of the front wall is

125Hz-2.817 sq. m

500hz-18.54 sq. m

2000Hz-11.82 sq. m

FOR TWO SIDE WALLS

Absorptive materials should be used

Area of each side wall=15*5=75msq.

Stage is occupying the area=3.5*.6=2.1

3stairs are occupying the area=.225

Rest wall area=75-2.1-.225=72.675

Door area=1.5*2.1=3.15Beam area=.3*15=4.5

So rest the wall surface area=65.02 where we will use two materials

50% 50%

If we are using drapery(1002/yd2,340g/m2,flat against wall) on 50%

of the wall:

125Hz-32.51*.04= 1.30

500Hz-32.51*.11= 3.572000Hz-32.51*.3= 9.753

Fibre glass

board

PLAN

drapery

Conceptual view

section

ply wood 50mm

Ply wood finish 50mm

False ceiling

Drapery 50 mm

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And rest 50% we are using drapery 1802/yd2,616g/m2,flat against wall

125hz-32.15*.05=1.62

500hz-32.51*.35=11.37

2000hz-32.15*.38=12.35

Effective area of door:

125hz-3.15*.1=.315

500hz-3.15*.05=.157

2000hz-3.15*.04=.126Effective area of beam

125hz-4.5*.01=0.45

500hz-4.5*.02=.9

2000hz-4.5*.02=.9

So total effective area of

the side wall each is:

125hz-2.715500hz-5.59

2000hz-11.74

So the total effective area of the concert hall is:

For

125hz=5.94+5.557+2.817+2.715+2.715+45=64.74

For500hz=33.75+4.474+18.54+5.59+5.59+45=112.9

For 2000hz-

29.16+3.006+11.82+11.746+11.746+45=112.4Effective area is achieved approximately .

and so reverberation time achieved comes

1.5 in 125hz,

0.66 in 500hz, .98 in 2000Hz.

Sound is invisible, but has the power to changethe character of space we occupy

Absorption co-efficient of one person=.45

The concert hall has capacity of 100 people

sitting... so the total

absorption co-efficient of the total audience

is .45*100=45

The materials used for the concert hall:

Ceiling- Acoustic tile & wood tongue and

grooved roof decking

Rear wall- ply wood 3mm paneling over

31.7mm air space

Side wall-page board over 75 mm fibre glass

bar & drapery 1002/yd2, 340g/m2, flat against

wall

Front wall-drapery 1802/yd2,616g/m2,flat

against wall& drapery1002/ yd2, 612g/m2

pleated

Doors-solid wood panel

Beam-concrete (painted and sealed)

iv

Monika SmruteeSatyam LipsaShinjini (B) LopaAnubhab Avash Lorisha

INTERIOR VIEW

auditorium accoustical calculations.ppt

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