# ANNA university previous question papers – BE – Architectural acoustics -VI Sem

## B. ARCH.  DEGREE EXAMINATION,V SEMESTER

PART – A  (10 x 2 = 20 marks)

1.Explain the terms “sound pressure” and “sound intensity”

2.What is the increase in sound pressure level if the intensity is doubled?

3.Explain what is meant by timbre?

4.What is “Sound insulation” and  “Sound isolation”?

5.What is meant by reverberation time?

6.Explain briefly on Helmholtz resonators.

7.Explain the development of sound field in open air.

8.What are the acoustical considerations in the design of a School building?

9.Explain what is meant by “Environmental Acoustics”?

10.Explain what is meant by Noise reduction factor?

PART – B (5 x 16 = 80 marks)

11.Calculate the reverberation time at 500 Hz in a hall with following surface finishes and seating conditions.

Item                                                                        Absorption Coefficient

750 m2 brick wall                                                                 0.02

540 m2 plaster on solid backing                                             0.02

65 m2 glass window                                                              0.10

70 m2 curtain                                                                       0.40

130 m2 Acoustic board                                                          0.70

300 m2 wood block floor                                                        0.05

In addition there are 500 occupied seats each contributing 0.4m2 units of absorption. The Volume of the hall is 4000m3.

12.a)    Explain the various acoustic phenomenon associated with room acoustics.

OR

12.b)    Describe the sound field produced by a source in a room. Explain how modification of absorption properties of the room will affect the field.

13.a) A lecture room 16m long, 12.5m wide and 5m high has a reverberation time of 0.7 sec. Calculate average absorption coefficient of surfaces using Eyring formula.

OR

13.b)Calculate the average sound reduction factor of a partition made of 24m2 of 115 mm brickwork and 6m2 of plate glass where sound reduction factors of brickwork and glass at certain frequency are 45 dB and 30 dB respectively.

14.a) Name four principles to be observed when considering sound insulation and say whether they are effective against airborne or structure–borne sound and how to apply these principles for a consultants office.

14.b) A new office building 25m high is to be erected close to urban motorway describe with appropriate sketches and details how noise levels in building from following sources could be reduced.

a) External noise from motorway

b) Internal noise from mechanical services.

c) Internal noise due to office.

15.a)Explain with sketches the Acoustical design for a television studio.

OR

15.b)    Explain with sketches the acoustical design for a radio studio.