Flashcards in Lecture 7 'Auditory Displays' Deck (27):
Sound amplitude is experienced as __________ whereas sound frequency is experienced as _______.
Decibel scale is___________, meaning +3 db (approx) is a ________ of sound power and + 10 db
(Q 60) The ossicles of the middle ear are which?
Pinna, tympanic membrane, and cochlea
Masking or Temporary (TSS) is defined as what?
relative recovery of sensitivity of hearing at 2mins after noise stimulus ceases
At old age, maximum hearing loss occurs at ______ Hz
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?
(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?
Adding two identical sources of sound = increase by 3 db so:
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?
Adding ten identical sources of sound = increase by 10 dB so:
(Q 59). At approximately which sound pressure level do hearing protection measures have to start?
(Q 61.) The phon scale does what?
(Q 64) At what sound frequency range do we have the lowest threshold of audibility (hearing)?
What two ways might noise (at the right level) focus attention on work?
- Masks mild distractors
- Promotes alertness and vigilance
How might too much noise threaten performance?
- Masks important auditory cues
- "Funnels" attention narrowly
Higher sounds can be masked by lower ones. What increase in dB level is needed to ensure a target sound is hear in nise?
+10db to +15db
What are three ways to protect yourself from noise?
control at SOURCE (less vibration)
control of PATH (baffling)
control at EAR (plugs/muffs)
A-weighted scale is used to measure what?
C-weighted scale is used to measure what?
Flat-weighted scale is used to measure what?
A = intensity of sound as ear hears it
B= intensity of sound as (almost) physically measured
C = intensity as physically measured
(Q 63) If you wish to measure physical sound energy alone, which decibel scale would you use?
What is the difference between auditory icons and earcons?
> 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)
(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?
What is audification?
Taking the natural sound and amplifying it (e.g. a stethoscope amplifies heart rate)
What is parameter sonification?
A signal from the world interpreted as sound (e.g. alarming of more radiation by more cackling noise)
(Q 62.) Which is the best example of “control at the source” when considering noise control in the
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.
B - REDUCE VIBRATION
What are Patterson's four criteria for alarms?
1. Audible, but not dangerous to ears
2. Not startling (rise time)
3. No interference with other signals
What is the "Cry Wolf" effect?
People distrust alarms and assume they are false
(Q 66). How does the “Cry Wolf” syndrome manifest itself?
Automated alarms produce more false alarms and misses so people lose trust in the automation.
According to Bliss et al (1995) how do humans respond to alarms?
"human probability matching" = most people match their response rate to the expected probability of true alarms