fhs final concepts

Method of limits + issues

Determine at what intensity the stimulus is detected as the intensity is increased from a low to high level and vice versa

Issues: Participant lacks engagement and presenter may be biased

Method of adjustment + issues

The participant adjusts the stimulus until they can either no longer detect the stimulus or just begin to detect it

Issues: more complicated, participant can't follow instructions

Method of constant stimuli + issues

Determine the percentage of 'yes' responses from a stimulus at a variety of different randomly presented intensities

Issues: requires a complicated programming to randomize trials

Absolute threshold

The lowest intensity at which a stimulus can be detected (reliably hear)Intensity which can be detected 50% of the time

Discrimination threshold

Minimal amount of change in a stimulus detected

Signal detection theory

Perception in general is controlled by two basic internal processes

-Sensory impression that on the average is dependent on the intensity of the signal

-Evaluation of this sensory impression by a decision process

spectrogram

long speech, multiple distribution

spectrum

short time window

complex wave

- combo of 2 or more sine waves

frequency is measured in

Hertz (Hz)

period formula

T=1/f

frequency formula

f=1/T

This type of diagram has

x axis - freq

y axis - amp

spectrum

This type of diagram has

x axis - time

y axis - freq

spectrogram

This type of diagram has

x axis - difference in level

y axis - freq

HRFT

This type of diagram has

x axis - time

y axis - amp

time domain, shows behavior of vibration across time

This type of diagram has

x axis - physical characteristics of stimulus

y axis - % of response

psychometric function

According to signal detection theory, perception is controlled by what two processes?

Sensory impression and decision process

STIFFNESS of the BM is greatest at ___ &decrease from the ____to ____

BASE, base, apex

Fourier Transform

decomposing a complex sound into its frequency components

analyzing the frequency composition of complex sounds

illustrating the relative amplitudes of the frequency components of a complex sound

particles of medium move parallel to the direction of wave

Longitudinal wave

How long a cycle of a sound wave is in distance

Wavelength

-measured in meters, millimeters

Phases of Pressure Change

• 0 = positive zero crossing

• 90 = positive at peak

• 180 = at a negative zero crossing

• 270 = negative peak

Medium

-What the sound travels through going from source to receiver

-can be wood, metal etc

How sound travels through different mediums

Gas: Fast Liquid: Faster Solid: Fastest

two factors pitch is affected by

duration & intensity

two properties of an object that influence its resonant frequency?

Mass, stiffness

particles of medium move perpendicular to the direction of wave

Transverse wave

sound waves are longitudinal or transverse waves?

longitudinal

but plotted as transverse

Sound's properties

Period/frequency, Amplitude, Phase

dB SL is relative to

threshold

The reference for dB HL is the ________ of typical hearing listener

threshold

Loudness recruitment

Rapid growth in loudness with increases in stimulus intensity

Similar loudness at very high stimulus levels

Resonant frequency

the natural frequency of an object where it tends to vibrate at a higher amplitude

impedance mismatch

loss of30 dB

hierarchy of auditory behavior

lowest to highest

detection

discrimination

recognition

resolution

low threshold

having high sensitivity and good audibility

high threshold

having low sensitivity and poor audibility

as frequency of pure tone increases, auditory thresholds ______

increases, decrease

(Lowest pure tone frequencies have relatively high absolute threshold)

ability to detect signal (in listeners with normal hearing) depends primarily on what two methods

frequency and presentation method

Lowest absolute thresholds are generally between what frequency range?

most sensitive to sounds within range of 1k to 5k hz

MAP and MAF

map-pressure measured at ear drum (using insert earphone)

maf-pressure measured in the sound field

dB SPL

what type of scale?

decibel sound pressure level

non-linear measure of intensity

+ 6 dB is

double the sound pressure

dB SPL scale uses _____ and ______ scale to present a wide range of pressure level

ratio

logarithmic

the reference for dB SL is the __________ of a given individual

threshold

Perception variable

Psychological perception attributed to sound, such as loudness, pitch, not measured by a device unlike stimulus variable

Two methods for measuring loudness using loudness scaling

Direct Magnitude Estimation

Direct Magnitude Production

Direct Magnitude Estimation

Direct Magnitude Production

DME- listener provides estimate of loudness compared to stimulus

DMP- listener equates loudness to values set by experimenter in relation to stim.

Loudness Growth Function

For sounds above 40 dB, loudness doubles when the sound level is increased by 10 dB

unit used in loudness scaling

sones

1 sone = 1000 Hz @ 40 dB SPL

the difference in level between the loudest and quietest sounds that a person hears (auditory response range)

dynamic range

LDL are also known as

uncomfortable loudness levels (UCLs) and threshold of discomfort (TDs)

what materials have high impedances

stiff and dense

Sounds transmitted to cochlea develops a ______________ pattern that always travels from base to apex

traveling wave

GRADATION OF STIFFNES

varies along length of basilar membrane

Pitch of pure tones mechanisms

-Temporal code: phase-locking

-Rate-Place code: tonotopic mapping of the BM

frequency discrimination

ability to detect changes in frequency over time

The neurons fire fastest with tones at their characteristic frequency

frequency tuning

The _____ end of basilar membrane is stiffer, narrower with less mass, and respond well to the _____ frequency sounds

base, high

Frequency difference limen is the lowest and pitch discrimination is the best for sounds ____

lower than 4kHz

The pitch of a complex periodic tone is close to the pitch of a ____ wave at the _________.

sine wave, fundamental

In the phenomenon of missing fundamental, the perception of pitch in a periodic complex tone is closest to _______

the pitch of the fundamental, even it is not presented in the complex tone

A bandpass filter _____ pure tones have frequency close to the center frequency of the filter, and _____ pure tones have frequency further away from the center frequency of the filter

passes, block

block, passes

attenuates, amplifies

amplifies, attenuates

The physiology mechanism of auditory filter is based on

basilar membrane' tonotopic mapping

middle ear's amplification effect

outer ear's resonance

none of the above

basilar membrane' tonotopic mapping

Basilar membrane' tonotopic mapping means: each location on the basilar membrane responds to a limited range of ________

frequency

notched noise method

psychoacoustic method to measure auditory filter width, done by using a noise that has a notch in the frequency band

Upward spread of masking (asymmetry of auditory filter)

Low frequencies mask high frequencies more than high mask low (not equal)

BM apex resonates w high or low freq

low freq

Upward spread of masking mechanism

BM tonotopic mapping

Which scenario below creates stronger masking?

Target speech is high frequency, noise is low frequency

Noise is high frequency, target speech is low frequency

Target speech is high frequency, noise is low frequency

Temporal integration (or summation)

he ability to combine information over time to enhance the detection or discrimination of stimuli

for signals shorter than 300ms duration and absolute threshold have _______ relationship

linear

for signals shorter than 300ms

duration decreases, absolute threshold decrease/increases ?

increases

Signals longer than 300 ms

Duration and absolute threshold have no relationship

As duration increases, audibility constant

Backward masking

the signal is presented before the masker

Forward masking

The signal is presented after the masker

Frequency resolution is the ability to separate one sound from complex sounds with multiple ________.

Temporal resolution is the ability to separate one sound from another in _______.

frequency, time

time, frequency

intensity, duration

frequency, intensity

frequency, time

If your absolute threshold for a 100-ms 1kHz tone is 10 dB SPL, your threshold for a 50-ms 1kHz tone is ____ 10 dB SPL.

higher than

lower than

higher than

How well can fluctuations in sound amplitude be detected?

Gap detection Amplitude modulation detection

How well can listeners follow rapid changes in a sound?

temporal resolution

Amplitude modulation (AM)

depth and rate

AM detection is very good up to______ Hz modulation rate

50-60 Hz

is Temporal Modulation Transfer Function (TMTF) is better with low/high frequency modulation

low freq

The perception of pitch is also affected by

duration and intensity of a sound

Frequency Difference Limen

smallest frequency difference necessary to tell that two sounds have a different pitch

how to measure Frequency Difference Limen (FDL)

what method?

Measured by a frequency discrimination task (using the method of constant stimuli)

(A listener hears two sounds with different frequency and select the sound with higher frequency)

Phase locking

the tendency of a neuron to fire action potentials at particular phases of an ongoing periodic sound waveform

Most sounds that give a sensation of pitch are ____ (that has a repetitive pattern).

periodic

Missing fundamental

the fundamental frequency of a complex sound can be heard even when this component is not presented

Lower - phase locked to the

Higher - phase locked to the

envelope, pure tone

pure tone, envelope

pure tone, envelope

what is the fundamental frequency?

lowest frequency in a complex tone

frequency resolution

The ability to separate out one component in a complex sound'

frequency resolution' = 'frequency selectivity'

Auditory filters: BM's tonotopic mapping

Each location on the basilar membrane responds to a limited range of frequencies, so each different point corresponds to a filter with a different center frequency

Spatial Dimensions

study how sounds are localized in space by using

our cue to localize the sound (HRTFs)

intensity of the sound changes as it hits our head

Two binaural cues for sound localization

Interaural Time Differences (ITDs)

Interaural Level Differences (ILDs)

Interaural level difference (ILD)

difference in sound pressure level reaching the two ears

ILDs depend on what two factors

Both the azimuth of the sound source and the frequency of the sound

Wideband (frequency band):

small/big time

window good/poor time resolution

good/poor frequency resolution

small time window

good time resolution

poor frequency resolution