Lecture 7 'Auditory Displays'

Question 1

Sound amplitude is experienced as __________ whereas sound frequency is experienced as _______.

Answer 1

amplitude (db)

pitch (Hz)

Question 2

Decibel scale is___________, meaning +3 db (approx) is a ________ of sound power and + 10 db

Answer 2

logarithmic

doubling

Question 3

(Q 60) The ossicles of the middle ear are which?

Answer 3

Pinna, tympanic membrane, and cochlea

Question 4

Masking or Temporary (TSS) is defined as what?

Answer 4

relative recovery of sensitivity of hearing at 2mins after noise stimulus ceases

Question 5

At old age, maximum hearing loss occurs at ______ Hz

Answer 5

4000

Question 6

What db is considered the action level where planning an education of the effect of work noise on hearing is implemented?

What db is does the need for protection and rest periods come about?

Answer 6

85db

90 db

Question 7

(Q 58) I play a sound at 40 dB. I then add another sound at the same frequency, and play it at 40 dB. What is the nearest approximation to the total sound power I now have, when I play the two sounds together?

Answer 7

Adding two identical sources of sound = increase by 3 db so:

43

Question 8

I play a sound at 4 dB, and add another nine sounds at 4 dB to that sound, what is the nearest approximation to the total sound power I now have when I play all the sounds together?

Answer 8

Adding ten identical sources of sound = increase by 10 dB so:

14

Question 9

(Q 59). At approximately which sound pressure level do hearing protection measures have to start?

Answer 9

85 dB

Question 10

(Q 61.) The phon scale does what?

Answer 10

+++++++

Question 11

(Q 64) At what sound frequency range do we have the lowest threshold of audibility (hearing)?

Answer 11

1000-3000 Hz

Question 12

What two ways might noise (at the right level) focus attention on work?

Answer 12

• Masks mild distractors

- Promotes alertness and vigilance

Question 13

How might too much noise threaten performance?

Answer 13

• Masks important auditory cues

- “Funnels” attention narrowly

Question 14

Higher sounds can be masked by lower ones. What increase in dB level is needed to ensure a target sound is hear in nise?

Answer 14

+10db to +15db

Question 15

What are three ways to protect yourself from noise?

Answer 15

control at SOURCE (less vibration)
control of PATH (baffling)
control at EAR (plugs/muffs)

Question 16

A-weighted scale is used to measure what?

C-weighted scale is used to measure what?

Flat-weighted scale is used to measure what?

Answer 16

A = intensity of sound as ear hears it

B= intensity of sound as (almost) physically measured

C = intensity as physically measured

Question 17

(Q 63) If you wish to measure physical sound energy alone, which decibel scale would you use?

Answer 17

dB(Flat)-weighted scale

Question 18

What is the difference between auditory icons and earcons?

Answer 18

> Auditory Icon makes use of natural everyday sounds

> Earcon is a structured audio message based on musical sounds (abstract representation of what they are referring to)

Question 19

(Q 65) A medical device plays different five-note melodies in the key of C major for different kinds of
medical alarm states. What kind of auditory displays are these?

Answer 19

An Earcon

Question 20

What is audification?

Answer 20

Taking the natural sound and amplifying it (e.g. a stethoscope amplifies heart rate)

Question 21

What is parameter sonification?

Answer 21

A signal from the world interpreted as sound (e.g. alarming of more radiation by more cackling noise)

Question 22

(Q 62.) Which is the best example of “control at the source” when considering noise control in the
workplace?

a. Providing barriers between workers and sound sources.
b. Reducing vibration of equipment and tools.
c. Providing baffling around equipment and tools.
d. Giving people scheduled rest periods out of noise environments.

Answer 22

B - REDUCE VIBRATION

Question 23

What are Patterson’s four criteria for alarms?

Answer 23

1. Audible, but not dangerous to ears
2. Not startling (rise time)
3. No interference with other signals
4. Informative

Question 24

What is the “Cry Wolf” effect?

Answer 24

People distrust alarms and assume they are false

Question 25

(Q 66). How does the “Cry Wolf” syndrome manifest itself?

Answer 25

Automated alarms produce more false alarms and misses so people lose trust in the automation.

Question 26

According to Bliss et al (1995) how do humans respond to alarms?

Answer 26

“human probability matching” = most people match their response rate to the expected probability of true alarms

Question 27

(Q 69) What did the Sanderson et al. (2008) study of HMDs and respiratory sonification show?

Answer 27

Anesthetists’ median ACCURACY to detect patient events is highest with respiratory SONIFICATION