Psychoacoustics

Front 1

An effort to determine what an organ can or is capable of doing - the resolving power of the sensory mechanism.

Back 1

Psychoacoustics

Front 2

the effort to determine the minimal magnitude of a stimuli that will elicit a response (absolute threshold)

Back 2

Sensitivity area of psychoacoustics

Front 3

Has to do with descriminations (activity)

Back 3

Resolving power area of psychoacoustics

Front 4

Psychological variables are for the most part uncontrolled. This type usually takes a few subjects and trains them rather than controlling for statistics.

Back 4

Classic Psychophysics.

Front 5

This type is based on statistics and mathematical models. It includes variables such as: the person's willingness to guess or motivation.

Back 5

Modern Psychophysics.

Front 6

Label. Examples include numbers on a football jersey, a telephone number, a social security number.

Back 6

Nominal

Front 7

Rank ordering (1st, 2nd, 3rd) (grades). The numbers have relationships but aren't equal intervals.

Back 7

Ordinal

Front 8

Equal. Each step represents the addition of a constant. The lowest level of measurement for mathematic operation (add, subtract).

Back 8

Interval

Front 9

Has an absolute zero and includes things like distance, weight, speed, time, temp. in Kelvins, the number of people in a room.

Back 9

Ratio

Front 10

What the subject actually hears

Back 10

Sensory Capability

Front 11

The manner in which a person responds. This also includes biases and criteria that affect a response.

Back 11

Response proclivity

Front 12

The stimulus is under the experimenter's control and the subject simply responds after each presentation.

Back 12

Method of limits

Front 13

A dB increment

Back 13

Step size

Front 14

Reduces the accuarcy because the actual threshold may lie anywhere between two discrete stimulus levels

Back 14

Too large a step size

Front 15

Permits a more precise estimate but also may be more tedious and may have a few "wasted" presentations due to test levels well above or below the threshold.

Back 15

A smaller step size

Front 16

During this experiment, an equal number of stimuli are presented at each level. The subject states whether there was a stimulus present during each trial. You then find the point at which the subject hears 50% of the time.

Back 16

Method of constant stimuli

Front 17

Enabled by the method of constant stimuli. Includes intervals during which the subject was asked if a sound was heard when no tone was really presented. This provides an estimate of guessing and performance or real trials is often corrected to account for this affect.

Back 17

Catch trials

Front 18

Adaptation of the clinic procedures to make them more clinically applicable.

Back 18

Adaptive procedures.

Front 19

Devised a tracking method which shares features both with the classical method of limits and adjustments.

Back 19

George Von Bekesy

Front 20

This method is the most used clinically. This simple method involves increasing the stimulus level when the subject does not respond to a presentation and decreasing the intensity when there is a response.

Back 20

Up-down (staircase) model.

Front 21

A group of stimulus presentations between two response reversals.

Back 21

Run

Front 22

The problem of absolute sensitivity is essentially one for describing how much sound intensity is necessary for a typical normal hearing person to

Back 22

Just detect the presence of a stimuli

Front 23

involves testing a subjects thresholds through earphones and then actually monitoring the sound pressures in the ear canal (b/w the ear phone and ear drum) that correspond to those thresholds.

Back 23

Minimal Audible Pressure (MAP)

Front 24

the subject is in a sound field and you test his/her thresholds for sounds presented via a loud speaker. The subject then leaves the sound field and the threshold intensity is measured with a microphone placed where his head has been.

Back 24

Minimal Audible Field (MAF)

Front 26

Minimal audible pressure are often stated in terms of the sound pressure generated by a ---- in a standard -----

Back 26

earphone/6 cc coupler

Front 27

This is the approx size of the ear canal and is used as a reference to do MAP

Back 27

6 cc coupler

Front 28

Found that lower intensity is needed to reach threshold in sound field than in ear phones. They found a six decible difference. (MAF freq curves fell below MAP.)

Back 28

Sivian and White

Front 29

Found that the ear canal resonance enhances pressure of a free field signal at the eardrum.

Back 29

Killian

Front 30

This has an advantage over monoaural.

Back 30

Binaural

Front 31

Missing a sound because you breath due to the occlusion effect, or because of your heart rate, coughing, etc.

Back 31

Physiological noises.

Front 32

This is where speech is found and human hearing is most sensitive in this area. Absolute sensitivity becomes poorer above and below these freqs.

Back 32

2000-5000kHz

Front 33

For durations of which are longer than 300 msec - the ear treats these as though they are infinitely long. Increases above the level do not change threshold level.

Back 33

Temporal integration or summation.

Front 34

The smallest perceivable difference between two sounds

Back 34

DL or jnd

Front 35

smallest perceivable difference in dB b/w two intensities

Back 35

ΔI

Front 36

smallest perceivable change in Hz b/w two frequences.

Back 36

ΔF

Front 37

ΔI

Back 37

absolute difference b/w 2 sounds

Front 38

ΔF

Back 38

relative difference b/w 2 sounds.

Front 39

actual amount of change for jnd - actual size of increment.

Back 39

absolute DL (frequency)

Front 40

the ratio of the increment to the stimulus.

Back 40

Relative DL (intensity)

Front 41

Your relative DL is a constant proportion which gives a perfect ratio.

Back 41

Weber's Law

Front 42

Formula for webers law

Back 42

ΔI/I=K

Front 43

The value of ΔI/I is a constant k regardless of the

Back 43

Stimulus level

Front 44

A high pitch is different in quality from a low pitch; it is not bigger as was the case when looking at intensity.

Back 44

Qualitiative continuum

Front 45

Quality changes continuously with changes in frequencies over the

Back 45

20,000 Hz Range

Front 46

Found that 20 Hz was the lowest tonal pitch

Back 46

Stevens and Volkmann

Front 47

Two tones only a few frequencies apart causes an in phase/out-of-phase pattern and a

Back 47

Beat

Front 48

Masking that results from interactions at the cochlea

Back 48

Peripheral Masking

Front 49

Masking that results from interactions with the central auditory nervous system

Back 49

Central Masking

Front 50

The number of cycles required to equal the energy in the tone is the

Back 50

Critical Ratio

Front 51

Zwicker, Flottorp, and Stevens showed that critical bands are about

Back 51

2 1/2 times as wide as critical ratios.

Front 52

Same stimulus presented to ear identically - at same time.

Back 52

Diotic

Front 53

Different stimulus presented simultaneously to each ear.

Back 53

Dichotic

Front 54

Stimulus presented to only one ear

Back 54

Monotic

Front 55

Same signal in each ear

Back 55

Monophonic

Front 56

Different signal each ear - not always simultaneous

Back 56

Stereophonic

Front 57

Done with headphones - perceived sound in head - (stenger effect)

Back 57

Lateralization

Front 58

In sound field-find space in area of sound source.

Back 58

Localization

Front 59

A summation of the acoustic energy reaching the 2 ears

Back 59

Binaural Summation

Front 60

Refers to sounds that are usually similar but not identical when they reach the two ears. One sound heard from two separate ears.

Back 60

Binaural Fusion

Front 61

The perception of sound in the ear in which it is louder without any awareness that it is also being presented to the ear where it is softer is the

Back 61

Stenger Effect