Question 1

Is STC related to airborne sound or structure- borne sound?

Accepted Answer

STC is related to airborne sound.

Question 2

Most of the noise produced in a busy restaurant or dining hall is

Accepted Answer

A) structure- borne sound. 
B) airborne sound. 
A) structure- borne sound. 
B) airborne sound. B

Question 3

Sound transmission class (STC)is a measure of the

Accepted Answer

A) sound- insulating property of a material with respect to airborne sound. 
B) sound- insulating property of a material with respect to structure- borne sound. 
C) sound- reflecting property of a material. 
D) sound- absorbing property of a material. 
A) sound- insulating property of a material with respect to airborne sound. 
B) sound- insulating property of a material with respect to structure- borne sound. 
C) sound- reflecting property of a material. 
D) sound- absorbing property of a material. A

Question 4

In architectural acoustics, we distinguish between airborne sound and structure- borne sound. Place the followin sounds in one of the above two categories.
Sound from the speaker in an auditorium 
Sound from hailstorm on an auditorium roof
Sound from the footsteps of a person walking on the floor
 Sound from someone knocking on an entry door of a house Sound from the orchestra in a concert hall

Accepted Answer

The answer of In architectural acoustics, we distinguish between airborne...

Question 5

The NRC of a material lies between

Accepted Answer

A) 0 and 10. 
B) 1 and 100. 
C) 0 and 100. 
D) 1 and 10. 
E) none of the above. 
A) 0 and 10. 
B) 1 and 100. 
C) 0 and 100. 
D) 1 and 10. 
E) none of the above.

Question 6

What is noise reduction coefficient, NRC? What is the unit of measurement of NRC? What are the theoretical minimum and maximum values NRC?

Accepted Answer

The NRC is the average value o

Question 7

Does the sound absorption coefficient of a material, a, vary with frequency? What is the unit of measurement of
a? What are the theoretical minimum and maximum values of a?

Accepted Answer

The value of a varies with fre

Question 8

The International Building Code requires minimum STC 50 for a party wall separating two dwelling units (condominiums or apartments). With this STC value, loud speech is heard across the party wall with some effort and music is heard easily. As a consulting acoustician, what STC value would you recommend to the architect/project owner for the party walls in an upscale condominium project?

Accepted Answer

STC 60. This will ensure the i

Question 9

What is a resilient channel made of and what is its purpose?

Accepted Answer

A resilient channel

Question 10

All building materials absorb sound to some degree. So, what is a sound- absorbing material?

Accepted Answer

A material whose sound absorpt

Question 11

The noise- reduction coefficient (NRC)of a material is evaluated between the frequency range of 250 Hz and 2 kHz because

Accepted Answer

A) most of the sound energy in the noise produced in buildings lies in the given frequency range. 
B) most of the sound energy in human speech lies in the given frequency range. 
C) the human ear is insensitive to noise outside the above frequency range. 
D) it is virtually impossible to evaluate this property outside the above frequency range. 
E) none of the above. 
A) most of the sound energy in the noise produced in buildings lies in the given frequency range. 
B) most of the sound energy in human speech lies in the given frequency range. 
C) the human ear is insensitive to noise outside the above frequency range. 
D) it is virtually impossible to evaluate this property outside the above frequency range. 
E) none of the above.

Question 12

Sound that is audible to human beings has a frequency lying between

Accepted Answer

A) 20 Hz and 20 kHz. 
B) 100 Hz and 800 Hz. 
C) 2 kHz and 20 kHz. 
D) 50 Hz and 50 kHz. 
E) 200 Hz and 20 kHz. 
A) 20 Hz and 20 kHz. 
B) 100 Hz and 800 Hz. 
C) 2 kHz and 20 kHz. 
D) 50 Hz and 50 kHz. 
E) 200 Hz and 20 kHz.

Question 13

What is the typical center- to- center spacing of resilient channels?

Accepted Answer

24 in. cen

Question 14

A resilient channel is used to attenuate airborne sound, whereas a resilient clip is used to attenuate structure- borne sound.

Accepted Answer

A) True 
 B)False

Question 15

The ear's perception of the loudness of sound, commonly called sound level, is measured by the decibel (dB)scale. What is the approximate sound level in conversational speech at 1 m away from a speaker? Sound level in shouting speech at 1m from a speaker? Sound level that causes pain in the ear?

Accepted Answer

Sound level in conversational

Question 16

The three important properties of sound waves are sound frequency, f, wavelength of sound, h, and the speed of sound, c. What is the relationship between them?

Accepted Answer

The answer of The three important properties of sound waves...

Question 17

A resilient clip consists of a small light- gauge steel member with a rubber pad fastened to it.

Accepted Answer

A) True 
 B)False

Question 18

STC represents the equivalent of average transmission loss (TL)of an assembly. The unit of measurement of TL is decibel (dB). Is the unit of measurement of STC also dB or different?

Accepted Answer

STC has no

Question 19

Explain what sound transmission class (STC)is.

Accepted Answer

STC is a single- number index that measu

Question 20

The sound created by human speech is

Accepted Answer

A) structure- borne sound. 
B) airborne sound. 
C) both A and B. 
D) neither A nor B. 
A) structure- borne sound. 
B) airborne sound. 
C) both A and B. 
D) neither A nor B.

Exam 8: Acoustical Properties of Materials

Is STC related to airborne sound or structure- borne sound?

Most of the noise produced in a busy restaurant or dining hall is

Sound transmission class (STC)is a measure of the

The NRC of a material lies between

What is noise reduction coefficient, NRC? What is the unit of measurement of NRC? What are the theoretical minimum and maximum values NRC?

Does the sound absorption coefficient of a material, a, vary with frequency? What is the unit of measurement of a? What are the theoretical minimum and maximum values of a?

What is a resilient channel made of and what is its purpose?

All building materials absorb sound to some degree. So, what is a sound- absorbing material?

The noise- reduction coefficient (NRC)of a material is evaluated between the frequency range of 250 Hz and 2 kHz because

Sound that is audible to human beings has a frequency lying between

What is the typical center- to- center spacing of resilient channels?

A resilient channel is used to attenuate airborne sound, whereas a resilient clip is used to attenuate structure- borne sound.

The ear's perception of the loudness of sound, commonly called sound level, is measured by the decibel (dB)scale. What is the approximate sound level in conversational speech at 1 m away from a speaker? Sound level in shouting speech at 1m from a speaker? Sound level that causes pain in the ear?

The three important properties of sound waves are sound frequency, f, wavelength of sound, h, and the speed of sound, c. What is the relationship between them?

A resilient clip consists of a small light- gauge steel member with a rubber pad fastened to it.

STC represents the equivalent of average transmission loss (TL)of an assembly. The unit of measurement of TL is decibel (dB). Is the unit of measurement of STC also dB or different?

Explain what sound transmission class (STC)is.

The sound created by human speech is

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