Readings Questions

Question 1

In Boothroyd’s paper on Speech Perception, what were the 4 principal factors involved in room acoustics?

Answer 1

Distance
Early Reverberation
Late Reverberation
Noise

Question 2

In Boothroyd’s paper on Speech Perception, how was the SNR described (i.e. what 2 components made up the “S” and which 2 made up the “R”)?

Answer 2

Effective Signal to Noise Ratio:
Signal = combination of direct speech and early reverberation
Noise = combination of actual noise and late reverberation
SNR = the decibel difference between signal and noise

Question 3

In Boothroyd’s paper on Speech Perception, what does “SAI” stand for? Describe it

Answer 3

SAI = Speech Audibility Index

• the proportion of the useful speech signal that is above the level of the effective noise
• developed because neither the SII or Articulation Index metrics accounted for late reverberation
• measured from -15 to +15 dB

Question 4

In Boothroyd’s paper on Speech Perception, what is a reasonable target for SAI?

Answer 4

70-75 percent (Effective SNR of 6-7 dB)

Question 5

In Boothroyd’s paper on Speech Perception, what are the ANSI standards for reverberation time in classrooms?

Answer 5

0. 6 seconds or less (small to medium sized)

0. 7 seconds or less (large sized)

Question 6

From the “Noise in Sound Rooms” reading, what does MPANLs stand for?

Answer 6

Maximum Permissible Ambient Noise Levels

Question 7

From the “Noise in Sound Rooms” reading, what was the rationale for requiring the ambient noise level to be measured for octave and 1/3 octave bands from 125-8000 Hz in the 1999 update, regardless of the test condition (ears covered or not) or test frequency range?

Answer 7

Upwards spread of masking

Question 8

From the “Noise in Sound Rooms” reading, what is RETSPLs short for?

Answer 8

Reference Equivalent Threshold Sound Pressure Levels

Question 9

From the “Noise in Sound Rooms” reading, what type of sound level meter is required by the 1999 standard to measure ambient noise?

Answer 9

Type 1 sound level meter having an octave or 1/3 octave band filter or equivalent

Question 10

From the “Noise in Sound Rooms” reading, what range of frequencies does the 1999 ANSI standard require be measured, regardless of the test condition or frequency range to be employed in the audiometric test room?

Answer 10

125-8000 Hz

Question 11

From the “Noise in Sound Rooms” reading, when should ambient noise levels be measured?

Answer 11

Annually and whenever there is a new source of noise operating within or in the vicinity of the test room

Question 12

From the ASHA Sound Field Measurement Tutorial, what are the 2 general uses of sound field?

Answer 12

• testing infants, young children, and individuals who will not tolerate earphones
• evaluating real ear characteristics of amplification systems (either with behavioural method or probe tube measures of insertion gain)

Question 13

From the ASHA Sound Field Measurement Tutorial, name 2 factors that could affect sound field testing.

Answer 13

• room acoustics
• background noise levels
• loudspeaker properties
• listener’s movements
• type of stimuli

Question 14

From the ASHA Sound Field Measurement Tutorial, what is the best location for test subjects to avoid large SPL changes?

Answer 14

Between the near/far field boundary and the direct/reverberant field boundary

Question 15

From the ASHA Sound Field Measurement Tutorial, name 2 of the 4 things that can influence the SPL at any given point in the room enclosure.

Answer 15

• source intensity
• directional characteristics of the source
• acoustic absorption of the room
• the objects within the room

Question 16

From the ASHA Sound Field Measurement Tutorial, what is the stimuli of choice for sound field measurements? Name 2 reasons why.

Answer 16

Frequency modulated tones

• ensure uniformity of the sound field
• ensure accuracy of audiogram slope measurement through frequency specificity in the signal
• good threshold measurement efficiency
• result in a more consistent sound level throughout a room than AM tones

Question 17

From the ASHA Sound Field Measurement Tutorial, the frequency of calibration measurements should be identical to that used for _____, generally once every ____ months.

Answer 17

Earphones; 3

Question 18

In Mueller and Killion’s article “Count the Dots”, what is this method used for?

Answer 18

It’s an easy method for calculating the Articulation Index

• isn’t copyrighted, so it’s accessible
• method to make routinely measured hearing thresholds meaningful regarding the understanding of speech
• e.g. used to explain to patients why high frequency hearing loss results in difficulty with speech in noise by covering the dots

Question 19

In Mueller and Killion’s article “Count the Dots”, how can their index be used for hearing aid fittings?

Answer 19

• it’s a good estimate of the audibility of speech inputs, which leads to the potential benefits of hearing aid use
• can conduct sound field- aided audiogram then count the dots that are audible to estimate hearing aid benefit for speech in quiet
• the more aided dots, the better

Question 20

In Mueller and Killion’s article “Count the Dots”, how has the new version changed from the old one?

Answer 20

• it takes high frequencies into account
• based on the SII importance function, so a few dots were removed from the lower frequencies and added to the higher frequencies (still have 100 dots total)

Question 21

In Mueller and Killion’s article “Count the Dots”, what would 65% audible dots indicate?

Answer 21

An AI of 65%

Question 22

In Mueller and Killion’s article “Count the Dots”, what speech level do the 100 dots represent?

Answer 22

60 dB SPL

Question 23

In Mueller and Killion’s article “Count the Dots”, does the theoretical relationship between AI and intelligibility apply equally to individuals of all hearing levels?

Answer 23

No - only to those with normal hearing