Unit 1 Sound

Question 1

What is Reverberation Time

Answer 1

The time taken for sound to decay (1)

Sound absorbed by interactions with the surface of a room

Question 2

What are sound waves

Answer 2

1. Transvers and longitudinal

Question 3

What is wavelength (m)

Answer 3

The distance from one point on a wave to the same point on the next wave.

Question 4

What is amplitude (m)

Answer 4

The maximum extent of a vibration measured from the point of equilibrium

Question 5

What is frequency (Hz)

Answer 5

The number of waves passing a point per second

Question 6

What is the formula for wave speed

Answer 6

Wave speed (m/s) = Frequency (Hz) x Wavelength (m)

v = f x λ

Question 7

What is the formula for period (s)

Answer 7

Period (s) 1 / Frequency (hz)

1 / f

Question 8

What is the formula for measuring the speed of sound

Answer 8

Speed (m/s) = Distance (m) / Time (s)

Question 9

Characteristic of sound

Answer 9

1. Cant travel through a vacuum

2. speed of sound is slowest in gasses, faster in liquids and fastest in solids

Question 10

What is amplitude/Loudness and what is it measured in

Answer 10

1. Size of vibration which determines how loud the sound is

2. Measured in decibels

Question 11

What is the difference between sound and noise

Answer 11

Sound - vibrations transmitted through air or another medium capable of being detected by humans ears

Noise - A sound that is loud, unpleasant, unexpected, or undesired

Question 12

What are the factors that cause a difference in sound

Answer 12

1. Tone
2. Pitch
3. Intensity

Question 13

What is tone

Answer 13

1. Refers to sound quality

Question 14

What is pitch

Answer 14

subjective impression about the highness or lowness of a tone.

Question 15

What is intensity

Answer 15

Amount of energy that is transported past a given area of the medium per unit time

Question 16

How can noise effect poeple

Answer 16

1. May cause annoyance
2. May cause hearing damage

Acoustic environment must be designed to avoid detrimental effects

Question 17

What are the negative affects of Nosie

Answer 17

1. damage to hearing
2. Disturbance of sleep
3. Poor performance of tasks
4. impaired alertness
5. Increased fatigue

Question 18

How do we reduce sound

Answer 18

1. Design it out before it becomes a factor
2. Reduce it at source
3. Insulate sound
4. PPE to be worn where exposure exceeds 85db

Question 19

What is refection

Answer 19

Molecules of air pushed further apart

Question 20

What is sound

Answer 20

A form of energy, which is transmitted through air as a pressure wave

Question 21

What factors affect acoustics

Answer 21

1. Sound reduction indices
2. Reverberation Times
3. Noise Criteria indices

Question 22

What value represents the threshold of hearing and sensation of pain

Answer 22

1. 0.00002 N/m² Threshold of hearing

2. 20N/m² sensation of pain

Question 23

What is sound intensity

Answer 23

Power of sound wave per unit area (w.m²-2)

Question 24

What is reverberation

Answer 24

Multiple random blended repetitions of sound

Question 25

What is reverberation time

Answer 25

the time required for sound in a room to decay

Question 26

What is sound absortion

Answer 26

The conversion of sound to energy

Question 27

What is airborne noise ?

Answer 27

Sound waves transmitted from a source to a receiver through the air

Question 28

What is structure-borne noise

Answer 28

Noise caused by vibration from within the building by footsteps or machines. The vibration is directly transferred through the buildings structures and materials

Question 29

What three ways does airborne sound travel

Answer 29

1. Through openings in a structure 2. By direct transfer through the structure 3. By direct transfer along the structure

Question 30

How can the building/ design layout control noise

Answer 30

1. By positioning rooms which are less sensitive to noise to act as screens between noise sources and quite areas. 2. Use higher density materials 3. Double glazed windows, thicker flooring/ wailing

Question 31

How can airborne sound be controlled

Answer 31

Through tick dense walls, Carpets using fibreglass quit in cavity wall and ceiling any air passaged around windows doors etc.

Question 32

What is sound absorption

Answer 32

1. the transfer of sound waves' kinetic energy into thermal energy Curtains, furniture and other textiles contribute to total absorption. Also known as natural absorption.

Question 33

Explain two reasons for the need to consider ‘noise criteria indices’ when designing the new building

Answer 33

Noise criteria indices are specific for a type of use of a room (1) and are linked to the maximum recommended noise level for a specific use (1) Building regulations set performance standards for noise levels (1) which can be met by specifying appropriate materials (1)