Vocabulary Terms for Chapter 12

Vocab terms to study for Exam #4 in Chapter 12.

Location

Location

We consider the mechanisms that enable us to determine where sound is coming from & the mechanisms that enable us not to be confused by sound waves that are bouncing off the walls of a room. A single sound tends to come from one location & to move continuously.

Organization

We consider how we can separate individual sounds when many sounds are occurring simultaneously.

Auditory Space

Perception of where sounds are located in space. Surrounds a listener’s head in all directions, existing wherever there is sound.

Auditory Localization

The locating of sound sources in auditory space.

Binaural Cues

A location cue that depends on BOTH ears. Based on the comparison of the signals received by the left & right ears.

Monaural Cues

A location cue that depends on just ONE ear. Needed to locate sounds along the elevation coordinate. Primary monoaural cue for localization is called spectral cue.

Azimuth Coordinates

Specifies locations that vary from left to right relative to the listener.

Elevation Coordinates

Sound locations that are up & down relative to the listener.

Distance Coordinates

How far the sound source is from the listener.

Interaural Level Difference (ILD)

The difference in sound pressure level reaching the two ears.

Acoustic Shadow

Shadow created by the head that decreases the level of high-frequency sounds on the opposite side of the head. This is the localization cue of interaural level difference.

Interaural Time Difference (ITD)

Difference between the times that sounds reach the two ears.

Cone of Confusion

A surface in the shape of a cone that extends out from the ear. Sounds originating from different locations on this surface all have the same interaural level difference & interaural time difference. So location information provided by these cues is ambiguous.

Spectral Cue

The distribution of frequencies reaching the ear that are associated with specific locations of a sound.

Direct Sound

Sound that reaches the listener’s ears straight from the source.

Indirect Sound

Sound that is reflected off of environmental surfaces & then to the listener.

Precedence Effect

We perceive the sound as coming from the source that reaches our ears first. Governs most of our indoor listening experience.

Auditory Scene

The array of all sound sources at different locations in the environment.

Auditory Scene Analysis

Process by which sound sources in the auditory scene are separated into individual perceptions.

Onset Time

Sounds that start at different times are likely to come from different sources.

Similarity of Timbre & Pitch

Sounds that have the same timbre or pitch range are often produced by the same source.

Auditory Stream Segregation

The effect that occurs when a series of sounds that differ in pitch or timbre are played so that the tones become perceptually separated into simultaneously occurring independent streams of sound.

Proximity in Time

Sounds that occur in rapid succession usually come from the same source.

Auditory Continuity

Sounds that stay constant or change smoothly are usually from the same source.

Effect of Past Experience

An example demonstrating the effect of past experience is from an experiment by Dowling & Hardwood (1986).

• The melody “Three Blind Mice” was played with notes alternating between octaves.

• Listeners found it difficult to identify the song.

• But after they heard the normal melody, they could hear it in the modified version using melody schema.

Multisensory Interactions

Use of a combination of senses. They usually complement each other.

Ventriloquism Effect (AKA, Visual Capture)

When sound is heard coming from a seen location, even though it is actually originating somewhere else.

Two-Flash Illusion

An illusion that occurs when one flash of light is presented, accompanied by two rapidly presented tones. Presentation of the two tones causes the observer to perceive two flashes of light instead of one. S

Sound & Motion

They interact!

Echolocation

Locating objects by sending out high-frequency pulses & sensing the echo created when these pulses are reflected from objects in the environment. (EX: Echolocation is used by bats, dolphins, & some blind people too).