Physics

Front 1

Method-Method of limits

Back 1

The sound is presented -> the subject replies they heard it -> the sound is dropped a discrete amount and presented again-> repeated until the subject no longer perceives the sound and the run is terminated. Ascending series stimuli begins below threshold and increased until response is obtained. The threshold for each series is an average between ascending and descending.

Front 2

Method of limits disadvantages

Back 2

bias from anticipation of where response should change.
Limited in terms of step size and inefficiently placed trials. Large step sizes are inaccurate and small ones are inefficient

Front 3

Method of limits advantages

Back 3

descending and ascending runs possible, average of two minimizes bias. Less bias if ascending and descending are randomized.

Front 4

Method of adjustments-Method

Back 4

the stimulus is controlled by the subject, not discrete step size (varied continously), both ascending and descending, threshold is average of audible and inaudible threshold.

Front 5

Method of adjustments-advantages

Back 5

Listeners enjoy most

Front 6

Method of adjustments-Disadvantages

Back 6

Contaminated by stimulus persistence (preservation of the response) bias, harder for investigator to have same degree of control

Front 7

Method of limits disadvantages

Back 7

bias from anticipation of where response should change.
Limited in terms of step size and inefficiently placed trials. Large step sizes are inaccurate and small ones are inefficient

Front 8

Method of constant stimuli-Method

Back 8

various stimulus levels are presented in random order (a range of intensities based on a previous experiment that encompass the threshold), a step size is selected and the intensities are presented at random. The threshold is the 50% point.

Front 9

Method of constant stimuli- disadvantages

Back 9

1. Not used in clinic
2. requires many trials (inefficient)
3.no certainty if have liberal or conservative responder

Front 10

Method of limits advantages

Back 10

descending and ascending runs possible, average of two minimizes bias. Less bias if ascending and descending are randomized.

Front 11

Method of constant stimuli- advantages

Back 11

1. can include catch trials
2. greater precision of measurement
3.allows direct estimation of guessing behavior

Front 12

Psychometric Function

Back 12

shows the probability (percentage) of responses for different stimulus levels

Front 13

two-alternative forced choice procedure-

Back 13

presented with two noises in succession, one of which has the tone. After listening to both stimuli, must decide whether the tone was present for first one or the second. Similarly in a 4AFC the subject must decide which contains the tone of 4 stimuli. often called interval forced choice.

Front 14

Adaptive procedure

Back 14

the level at which the stimulus is presented depends upon how the subject responded to the previous stimuli.

Front 15

BUDTIF

Back 15

Block up down temporal interval forced choice procedure- Subject is presented with two stimulus intervals during each trial an must indicate which interval contains the stimulus

Front 16

Miss

Back 16

Signal present, no response

Front 17

Correct Rejection, true negative

Back 17

No signal, no response

Front 18

False positive

Back 18

response, no signal

Front 19

hit

Back 19

response, signal present

Front 20

minimum audible pressure

Back 20

Subject's thresholds are tested through earphones and the spl is monitored in the ear canal

Front 21

Minimum audible field

Back 21

Subject is seated in a soundfield and the threshold intensity is then measured with a microphone placed where his head had been

Front 22

The missing 6 dB! Why?????

Back 22

Bianaural advantage, pinna cues, head noise, ear canal resonances, head defraction effects

Front 23

Weber's Law- Frequency
Δf/f= K

Back 23

Predictive DL =.002 (Weber’s law is true for 400-2k)
Duration matters especially with short duration < 200 msec, task become more difficult, JND increases
Short duration <250 msec/10 (decade change) harder to detect by about 10 dB
If stimulus is 25 dB SL (clearly audible), performance of frequency stimulation will not change

Front 24

Weber's Law- Intensity
ΔI/I= K

Back 24

(slight slope, near miss to Weber’s law)
Fairly constant, not exactly constant, improves slightly as starting intensity increases

Front 25

Weber's law- Duration
Δt/t= k

Back 25

Weber’s law is not true for duration- partially true for range depending on starting value, if T is between 50 & 500 msec any T value between will be 10% or .10 for stimulus silence interval

Front 26

Critical band (masking)

Back 26

Bandwidth where abrupt changes occur

Front 27

Informational masking

Back 27

Tones will interfere when outside critical band, neural phenomena, central masking.

Front 28

Energetic masking

Back 28

Masking caused by tones

Front 29

Sone

Back 29

is equal to the loudness of a 1,000 Hz tone presented at 40 dB SPL.

Front 30

Phon

Back 30

unit of loudness level. all sounds that are equal in phons have the same loudness even though their physical magnitude may be different..

Front 31

backward masking or pre-masking

Back 31

masker is preceded by signal, greater threshold shifts than forward masking, decreases dramatically as delayed is lengthened from 15-20 msecs.

Front 32

forward masking or post-masking

Back 32

masker is followed by signal,

Front 33

K= Δs/s

Back 33

· Constant % of the starting frequency
· Difference needed for detection is a proportion of the starting value

Front 34

specific Weber values

Back 34

· Freq= value K= .002 = Δf/f
· Intensity= ΔI/I= .5 -1 dB
· Duration= ΔT/T= .1 for 50-500 msec

Front 35

masking

Back 35

presence of one sound elevate your hearing of another sound

Front 36

Upward spread of masking

Back 36

next most masking in higher frequency relative to the low frequency direction

Front 37

masking takeaways

Back 37

1. Most masking at masking frequency
2. Upward spread- next most high
3. Ear non-linear- little dips in masking fx show multiples (harmonics)

Front 38

critical ratio

Back 38

The tone needs to be 10 dB greater than the spectrum level of the background noise

Front 39

Ratio

Back 39

Ratio levels are similar to interval levels but allow for the specification of ratios between numbers, which requires the presence of a true zero. Most physical measures are ratio level measurements (e.g., length, velocity, etc.) where zero represents the absence of that quantity. This allows us to say that some unit on a scale is so many times greater or less than another unit.

Front 40

Magnitude Estimation

Back 40

without matching or comparing- 1 sound listen to loudness of pitch, 1st sound assign a # to it (if assign 50, 2nd sound 2x loud= 100), then have own personal system, quality of ratio scale, some have baseline

Front 41

Loudness Recruitment

Back 41

loudness growth curve, rate of growth is much faster after threshold is reached, eventually catches up to normal ear

Front 42

Temporal integration of loudness

Back 42

short duration increase duration, loudness grows up to 250 msec

Front 43

Duplex Theory

Back 43

explains localization on the basis of time differences between the ears at lower frequencies and level differences between the ears at higher frequencies

Front 44

interaural time differences

Back 44

provide localization cues for the lower frequencies

Front 45

interaural level differences or interaural intensity differences

Back 45

Provide localization cues for the higher frequencies

Front 46

horizontal directions are expressed as angles of azimuth

Back 46

yep

Front 47

weber fraction

Back 47

absolute DL divided by the value of the starting level