131 final Flashcards
Frequency Selectivity
the ability of the auditory system to resolve or separate out the different frequency components of a sound wave
Iso-level curve
Basilar membrane response as a function of the frequency of a pure tone for various levels of the tone
Tuning Curve
The level of a pure tone needed to produce the same basilar membrane response
Basalward Shift
traveling wave must move toward the higher frequency regions of the basilar membrane to compensate for the shift to lower-frequency excitation
Nonlinearities
input is not equal to the output
Compression
as the value of the input increases, the same change in the input generates a smaller and smaller change in the output
Motility
outer hair cells expand and contract due to protein prestin
Two-tone Suppression
reduction in response to one frequency component when another frequency component is added
Distortion (missing fundamental)
frequency components that are not present in the input are present in the output
Masking
the obscuring of one sound by another
Critical Bandwidth (ERB)
A measure of the “effective bandwidth” of the auditory filter
Rectangular filter such that the peak transmission is the same and the total power (area under the curve) are the same -> ERB
Excitation Patterns
a plot of the output of filters as a function of center frequency
Spectral-notch Masking
can be used to estimate the shape and bandwidth of the auditory filter
Psychophysical tuning curves
the level of pure tone needed to mask a pure tone signal
Spectral excitation pattern
sine tone versus complex signal
Loudness Definition
ANSI: that attribute of auditory sensation in terms of which sounds can be ordered on a scale extending from quiet to loud
Textbook: loudness is the subjective magnitude of sound
Dynamic Range and Threshold (of loudness)
0 - 120 dB SPL
Equal loudness contours
hearing is most sensitive between 1000 and 6000 Hz
loudness level
variation flattens out at very high sound levels
Phons
hybrid measure that relates sensitivity of the auditory system to frequency and sound level on an interval scale
Sones
perceptual measure that relates soundness to a fixed standard on a ratio scale
sound A is twice as loud as sound B if its sone value is twice that of sound B
Magnitude Estimation
assign a number to each sound according to its loudness
Magnitude Production
subject adjusts the level of a test sound until it has a specified loudness
Specific loudness
a calculation of the output at each auditory filter
Just noticeable difference
the minimum levels of an acoustical change at which subjects can hear a difference
Weber’s Law
The property by which the small detectable increment in intensity is proportional to the baseline intensity means the increase in intensity required for you to notice a change
“near miss” to Weber’s Law
as sound level increases more auditory filters become active
coding of spectral amplitude
low level - formants of the acoustical spectrum are represented in the neural output
high level - the neurons are saturated and formant information is lost
Neural Synchrony
improves with increased sound level
Pitch
pitch is the aspect of auditory sensation by which sounds are ordered on the scale used for melody in music
Range for Pitch
melodic pitch: 30Hz - 5000Hz
normal hearing: 20Hz - 20,000 Hz
Rate Place Coding
basilar membrane conducts frequency analysis, different areas on basilar membrane respond to different frequency levels
Temporal Coding
due to phase locking, the time pattern of neural spikes is at a multiple integer of the period of the signal
Basilar Membrane response to resolved and unresolved harmonics
nerve fiber tunes to resolved harmonics locks to the fine structure, unresolved locks to the envelope
Pattern recognition model for pitch extraction
pitch is derived from the neural information about the frequencies of the individual, resolved partials
Temporal Model for pitch extraction
pitch is related to the time intervals between nerve spikes in the auditory nerve stemming from unresolved partials
Temporal Resolution
the ability to process fast changing stimuli, the separation of events in time
Backward Masking
masking of a tone by a sound that begins later
Forward Masking
masking of a tone by a sound that ends before the tone begins
Temporal window model
stage one: effect of the auditory filter on basilar membrane velocity, second stage: all values are squared, stage 3: sliding temporal window
Spectro-Temporal excitation pattern
represents the complete physiological transformation of the acoustical signal
Periodicity
the number of a pure tone that occur over a given length of time
Partial
a general term that can apply to any mode of vibration in a spectrum
Temporal Envelope
primary determinant in our classification of sound sources
Distortion Product
characterized by the introduction of frequency components in the output that were not present in the input
Resonant Frequencies of outer and middle ear
1.5 - 7 kHz
Basilar Membrane
separates out via traveling wave, the frequency components of a sound wave
Organ of Corti
holds inner and outer hair cells
Scala Media
a canal filled with endolymph that extends along the cochlea
Resolved harmonic
low numbered partial
Unresolved harmonic
high numbered partial
