Acoustics

Question 1

a series of distinct echoes. they are heard with sufficient loudness compared to the original sound

Answer 1

flutter echo

Question 2

The power carried by sound waves per unit area in a direction perpendicular to that area.

Answer 2

Sound intensity

Question 3

it is the ratio of absorbed energy to incident energy and is represented by α, and if the acoustic energy can be absorbed entirely, then α=1.

Answer 3

sound absorption coefficient

Question 4

formula for sound reverberation

Answer 4

T(subscript 60) =24ln10^1/c(subscipt 20) x V/S(subscipt a)

Question 5

an area through which sound waves fall to propagate, due to topographical obstructions or disruption of the waves via phenomena such as wind currents, buildings, or sound barriers

Answer 5

sound shadow

Question 6

occurs when reflected sound rays leap-frog one another and creep along the surface of the curve

Answer 6

sound creep

Question 7

A measure of acoustic energy emitted from a noise source; expressed in decibels.

Answer 7

Sound power

Question 8

it is the sound which is produced by an object when it vibrates at the same rate as the sound waves from another object.

Answer 8

sound resonance

Question 9

it is the difference in decibels between the intensity levels of two rooms separated by a barrier of a given transmission loss.

Answer 9

noise reduction coefficient (NRC)

Question 10

A form of energy propagated in waves that continues to subsist until filtered through a material turning into heat by friction

Answer 10

Sound

Question 11

defined as the measure of time after the sound source ceases that it takes for the sound pressure to reduce by 60dB

Answer 11

RT 60

Question 12

mostly effective for mid-range and treble tones, commonly used in low-height office partitions, wall/ceiling panels, etc.

Answer 12

porous absorbers

Question 13

(example problem) If the source room has 100 dB and what is transmitted is 70 dB, how much is the STC?

Answer 13

STC 30 dB

Question 14

A score given to a building’s surface (wall, ceiling, window, etc.) based on its ability to reduce sound coming through it.

Answer 14

Sound transmission class (STC)

Question 15

It is the technology of designing spaces, structures, and mechanical systems to meet the hearing needs effect of building design on the control of sound.

Answer 15

Architectural acoustics

Question 16

The pressure level of a sound, measured in decibels (dB)

Answer 16

Sound pressure level

Question 17

what is used to reduce structure-borne sound transmission?

Answer 17

sealant, with pockets of air in between to allow sound to bounce between them, until it gradually disappears

Question 18

result of the sound which causes the sound intensity in certain areas to be so low that is already insufficient for hearing

Answer 18

dead spots

Question 19

The SI unit of intensity

Answer 19

Watt per square meter (W/m2)

Question 20

Formula for sound transmission loss (STL)

Answer 20

TL = 10 log (1/t)

Question 21

they absorb sound energy as they dampen the air particles’ oscillation

Answer 21

porous absorbers

Question 22

the time it takes for the level to decay from -5dB to -65dB

Answer 22

RT 60

Question 23

Sound where the media is concrete, steel, wood, etc.

Answer 23

Structure-borne sound

Question 24

any porous or fibrous material such as textiles, fleece, carpets, foam, mineral wool, cotton wool, and special acoustic plasters

Answer 24

porous absorbers

Question 25

allows sound to pass through without much barrier

Answer 25

acoustical transparency

Question 26

the limit it takes for the level to decay from -5dB to -35dB multiplied by 2

Answer 26

RT 30

Question 27

it is the bending and spreading out of light or sound waves around an object

Answer 27

sound diffraction

Question 28

It is the branch of physics concerned with sound - deals with the production, control, transmission, reception, and effects of sound.

Answer 28

Acoustics

Question 29

Full circuit by a displaced particle.

Answer 29

Cycle

Question 30

the repetition of sound caused by the reflection of sound waves from a hard surface back to the listener.

Answer 30

sound echo

Question 31

sound becomes blurred, distorted, and confusing due to overlapping as well as it cannot be heard clearly.

Answer 31

long reverberation

Question 32

The number of times the cycle of compression and rarefaction of air occurs in a given unit of time.

Answer 32

Frequency

Question 33

defines the refraction angle corresponding to the transmitted wave. Thus, depending on the physical properties of each medium, the transmitted wave can be refracted either towards the vertical or towards the horizontal.

Answer 33

Snell's law

Question 34

A disturbance or oscillation that transfers energy progressively from point to point in a medium or space without advance by the points themselves, as in the transmission of sound or light

Answer 34

Waves

Question 35

Frequency of sound vibration; the predominant frequency of a sound as perceived by the human ear

Answer 35

Pitch

Question 36

a vibrational system that "runs" on sound pressure.

Answer 36

resonance absorber

Question 37

the direction of the sound that is sometimes brought about by the shape of the hall that concentrates the sound waves to a particular area of the hall creating a sound of large quality

Answer 37

focused sound

Question 38

Formula for noise reduction coefficient (NRC)

Answer 38

NR = TL+10log (A/S) where: A = total acoustical absorption (Sabins) S = area of a barrier

Question 39

The log ratio of the incident energy to the transmitted energy.

Answer 39

Sound transmission loss (STL)

Question 40

it occurs when soundwaves bounce back from the surface of a solid or liquid

Answer 40

sound reflection

Question 41

Father of modern architectural acoustics

Answer 41

Wallace Clement Sabine

Question 42

the persistence of sound after it has been stopped due to multiple reflections from surfaces such as furniture, people, air, etc. within a closed surface.

Answer 42

sound reverberation

Question 43

the phenomenon can affect the audibility of sound in an enclosure

Answer 43

sound reverberation

Question 44

the limit it takes for the level to decay from -5dB to -25dB multiplied by 3

Answer 44

RT 20

Question 45

it is used to evaluate the sound efficiency of materials.

Answer 45

sound absorption coefficient

Question 46

an advance form of reverberation where the sound is clearly and repeatedly after some time until it fades

Answer 46

sound echo

Question 47

It is usually a vibrating body that converts energy into vibration. It can be made louder or quieter.

Answer 47

Sound source

Question 48

What can acoustics do?

Answer 48

1. To meet hearing needs 2. Change the behavior of the users 3. Influence perception of space

Question 49

The back and forth motion of a complete cycle.

Answer 49

Vibration

Question 50

An aspect of real and virtual spaces that produces an emotional, behavioral, and visceral response in inhabitants; can produce feelings of isolation, warmth, and mystical sense.

Answer 50

Aural architecture

Question 51

it is the type of surface reflectance often described as a mirror-like reflection of light from the surface. In ___________, the incident light is reflected into a single outgoing direction.

Answer 51

specular reflection

Question 52

An oscillation in presence of the atmosphere which is capable of being detected by human ear.

Answer 52

Sound

Question 53

an acoustical defect occurs if there are two parallel reflecting walls

Answer 53

flutter echo

Question 54

when sound changes mediums (enters a different material) at an angle other than 90 degrees, it is bent from its original direction

Answer 54

sound refraction

Question 55

used to absorb low frequency sounds

Answer 55

membrane absorbers

Question 56

A longitudinal pressure wave in air or an elastic medium, especially one producing an audible sensation.

Answer 56

Sound wave

Question 57

it is the passage of sound from one room to another, or, from the exterior into a room in a building.

Answer 57

sound transmission

Question 58

Sound which the medium is air.

Answer 58

Airborne sound

Question 59

It is usually concerned with the human ear. The ______ can be influenced.

Answer 59

Receiver