Acoustics

Question 1

sound is…

Answer 1

a vibration or pressure wave that moves through a suitable medium such as air or structure at a frequency and intensity that can be detected by the human ear.
20Hz - 20kHz.

Question 2

Noise is…

Answer 2

unwanted sound.

Question 3

Building acoustics is…

Answer 3

the science of controlling noises in buildings including:
- minimising noise transmission from one space to another
- controlling the characteristics of sound within spaces themselves

Question 4

NR curves

Answer 4

Noise Rating Curves

Question 5

NC curves

Answer 5

Noise Criteria Curves

Question 6

RC Curves

Answer 6

Room Criteria Curves

Question 7

What are noise limiting curves used for?

Answer 7

to specify acceptable level of sound at different frequencies

Question 8

Airbourne sound is…

Answer 8

a sound which travels through air before reaching a partition.

Question 9

Impact sound is…

Answer 9

generated as a result of impact or a continuous vibration against a part of a building partition

Question 10

Reverberation

Answer 10

the continuation and enhancement of sound caused by multiple reflections between surfaces of a room.

Question 11

Reverberation time

Answer 11

how long it takes the sound to die away, defined as the time taken for a sound when stopped to decay by 60 dB

Question 12

Reverberation time - control

Answer 12

it needs to be controlled where good speech intelligibility is needed (lecture rooms), is controlled by adding sound absorptive material.

Question 13

Reverberation time - prediction

Answer 13

Sabine’s formula can give prediction of reverberation time. t=0.16V/A