Hearing Science Flashcards
Define psychoacoustics
relationship between acoustic world and our auditory image of this word
or.. how is sound perceived?
Weber’s Law
sensory perception; just noticeable difference is proportional to stimulus
Fechner
developed experimental methods to measure perception.
- basis of audiogram measurement
Helmholtz
physiology is the basis of perception
- invented a resonator that synthesized sound
- he showed that the of musical notes and vowel sounds is a result of their complexity
Bell
developing technologies for the telephone
- tools to control & manipulate sound
- masking
- threshold testing
describe how history of psychoacoustics has influenced the field of audiology
connection between psychoacoustics and audiology/the audiogram
concept of threshold in psychoacoustics
absolute threshold
softest sound you can hear for a threshold
terminal threshold
moment when changes from a perceived as sound to pain (the end point)
- gets so loud it is perceived as pain
difference threshold
smallest perceptible different (just noticeable difference), intensity and frequency that you can hear (perceive)
dynamic range
area in between
- no hearing loss
-sensorineural hearing loss (age related) the dynamic range would be narrow
method of adjustment
opposite of constant stimuli
-give the participant the control, change the limits themselves
- realistic, what the participant experiments in daily life
- barely audible, depending on the experiment
- unreliable; all in the patients hands
method of constant stimuli
decide in the beginning; present all of the tones
- levels in random order
- need to have some idea of in general of what there threshold is
- selected values ahead of time
-less biased
method of limits
presents a tone where the patient can hear it
- decrease the volume to where they cannot hear it
- cons: patients can learn the pattern really well
- motivated to pass a hearing test
modified hughson-westlake down 10 - 5 up
YES - decrease by 10 dB
NO - increase by 5 dB
record level when listener responds to 2 out of 3 beeps at the same level on an ascending run
- quicker improvement of method of limits
psychometric function and why is it used
an example of psychometric function for detecting a pure tone in quiet, which illustrates that performance increases with increasing signal level
define auditory masking
sounds are more difficult to hear by other sounds
the threshold of one sound is elevated by another sound
- intensity: frequency selectivity worsens with greater intensities
- fluctuations in timing: a fluctuating masker has dips with high SNRs
- frequency: upward spread of masking: low frequency sounds mask high frequency sounds better than the reverse
informational masking
presence of other sounds that compete for a listener’s cognitive processing or attention
- confusions (uncertainty) between the signal and masker that originate more centrally in the auditory system
e.g., speech, music, complex auditory scenes
energetic masking
traditional peripheral masking
released from forward masking
occurs when a sound (the signal) cannot be perceived due to the presence of a preceding sound (the masker)
masking relate to the critical band phenomenon
reduced audibility of a sound signal when in the presence of a second signal of higher intensity within the same critical band
how is masking used in audiology
introduction to noise to the non-test ear during a pure tone audiogram
-aims to ensure that the test ear hears the presented tone and is not ‘cross-heard’ by the non-test ear
define loudness
