Chapter 10: Hearing in the Environment

Question 1

interaural time difference (ITD)

Answer 1

The difference in time between a sound arriving at one ear verses the other.

Question 2

azimuth

Answer 2

The angle of a sound source on the horizontal plane relative to a point in the center of the head between the ears. It is measured in degrees, with 0 degrees being straight ahead. The angle increases clockwise toward the right, with 180 degrees being directly behind.

Question 3

medial superior olive (MSO)

Answer 3

A relay station in the brain stem where inputs from both ears contribute to detection of the interaural time difference.

Question 4

interaural level difference (ILD)

Answer 4

The difference in level (intensity) between a sound arriving at one ear verses the other. (Better for higher frequency, best for sound source location)

Question 5

lateral superior olive (LSO)

Answer 5

A relay station in the brain stem where inputs from both ears contribute to detection of the ILD.

Question 6

cone of confusion

Answer 6

A region of positions in space where all sounds produce the same time and level (intensity) differences (ITDs and ILDs)

Question 7

directional transfer function (DTF)

Answer 7

A measure that describes how the pinna, ear canal, head, and torso change the intensity of sounds with different frequencies that arrive at each ear from different locations in space (azimuth and elevation).

Question 8

inverse square law

Answer 8

A principle stating that as distance from a source increases, intensity initially decreases much faster than distance increases, such that the decrease in intensity is equal to the increase in distance squared. This general law also applies to optics and other forms of energy.

Question 9

spectral composition

Answer 9

farther away, higher frequencies decrease in energy more than lower frequencies . Farther away sounds muddy.

Question 10

relative amounts of direct versus reverbant energy

Answer 10

Cue to tell sound distance. Based on direct energy like whisper, and reverbant taking longer like singers voice.

Question 11

fundamental frequency

Answer 11

the lowest frequency component of a complex periodic sound.

Question 12

timbre

Answer 12

The psychological sensation by which a listener can judge that two sounds with the same loudness and pitch are dissimilar. Timbre quality is conveyed by harmonics and other high frequencies.

Question 13

attack

Answer 13

The part of a sound during which amplitude decreases (offset).

Question 14

decay

Answer 14

The part of a sound during which amplitude decreases (offest).

Question 15

source segregation/ auditory scene analysis

Answer 15

Processing an auditory scene consisting of multiple sound sources into separate sound images.

Question 16

auditory stream segregation

Answer 16

The perceptual organization of a complex acoustic signal into separate auditory events for which each stream is heard as a separate event.