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8 Cards in this Set
- Front
- Back
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How do magnitude estimation and magnitude production tests work?
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Magnitude estimation: person gives number as to how much louder one sound is than another.
Magnitude production: Adjust the level of one sound until it is twice as loud as the other. |
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What is the usefulness of the sone scale?
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Expresses that loudness is proportional to the power of the sound intensity. Sone scale is logarithmic, so for SPL >40dB, sone scale has constant slope: 4x loudness = difference of 4 sones
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What is the total activity model of loudness?
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The model of loudness coding that says that you sum the activities of nerves at all characteristic frequencies to get the overall loudness.
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What are two ways of quantifying the just noticeable difference (JND) in intensity discrimination experiments?
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Weber fraction: ΔI/I, I=baseline or pedestal sound intensity, and ΔI is increment added to pedestal that can just be detected.
ΔL:( I+ΔI)/I |
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How does the spread of excitation theory respond to the dynamic range problem (nerve fibers being saturated)?
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By using nerve fibers tuned to frequencies far away from the stimulus frequency, these nerves will not be saturated and can represent change in loudness by a change in firing rate.
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Why do excitation pattern plots for the basilar membrane with a particular pure-tone stimulus exhibit a sharper slope below the char freq and and shallower slope above the char frequency?
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B/c if we think of the BM as a bank of band-pass filters, due to the active mechanism, the higher-freq slopes of each filter are steeper than the lower-freq slopes. Thus filters with characteristic frequencies above the pure tone stimulus will pass more of the signal through their broader left sides, while filters with characteristic frequencies below the pure tone stimulus frequency will cut off more of the signal. Thus the excitation plot of the basilar membrane in response to a pure tone will have a steep slope at lower frequencies and a broad slope at higher frequencies, resulting in a shape that is the mirror image of a filter shape.
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How does loudness coding by phase locking work?
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Increasing the intensity of a pure tone in the presence of noise can increase the degree of regular, synchronized firing to the tone, even when the nerve fiber is saturated and cannot change its firing rate.
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Characteristics of Low SR and High SR nerve fibers, and how they may solve the dynamic range problem
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High SR fibers have more pronounced change in firing rate over change in level, more sensitive to lowest levels, but saturate at rel low levels
Low SR fibers shallower slope, less sensitive, but larger range, saturate at high levels More High SR than Low SR |
