Unit 3

Stimulus for Hearing

Movement of air molecules caused by vibrating sound sources carried by waves.

Sine Wave

A pure, smooth wave that represents the most basic kind of sound stimulus.

Frequency

The number of cycles per second, measured in Hertz (Hz).

Amplitude

The height of the waveform, measured in decibels (db); higher amplitude means louder sound.

Complexity

The number of pure tones combined together in a sound.

Pitch/Tone

The perceived highness or lowness of a sound, such as musical notes.

Loudness

The perception of sound intensity, typically measured around 80dB for normal speech.

Timbre

The quality of sound that distinguishes different types of sound sources.

Equal Loudness Curves

A graph showing that we are most sensitive to mid-range frequencies (500 Hz to 5000 Hz).

Interaural Time Difference (ITD)

The difference in time it takes for a sound to reach both ears, used to locate sound direction.

Interaural Intensity Difference (IID)

The difference in sound intensity reaching both ears, used to locate high-frequency sounds.

Cone of Confusion

Points in space where sound sources create identical interaural time and intensity differences.

Octave

A doubling or halving of frequency; the same note at a different pitch.

Harmonic

Extra vibrations that occur along with the main vibration of a sound.

Place Theory

Theory stating different locations along the basilar membrane respond to different pitches.

Temporal Theory

Theory suggesting pitch perception is based on the timing of neuron firing rates.

Phase Locking

When neurons fire at the same point in a sound wave cycle to match the rhythm.

Volley Principle

Groups of neurons firing in sequence to keep up with higher frequency sounds.

Fusion Effect

When two sounds that are close in time are perceived as a single sound.

Precedence Effect

The brain prioritizes the first sound heard if two identical sounds come from different places.

Echolocation

The use of reflected sound waves to perceive the environment, commonly used by some blind individuals.

Architectural Acoustics

The science of designing spaces to control sound behavior indoors.

Outer Ear

The part of the ear that collects sound waves and funnels them to the eardrum.

Middle Ear

The part of the ear that amplifies vibrations from the eardrum to the cochlea.

Inner Ear

The part of the ear converting mechanical energy to neural signals for the brain.

Cochlea

A spiral-shaped organ in the inner ear responsible for converting sound vibrations into nerve impulses.

Scala Media

The middle chamber of the cochlea that contains the Organ of Corti for sound perception.

Neural Code for Pitch Perception

The brain's method of interpreting pitch through timing and place theory.

Segmentation/Parsing

The ability to identify separate words in a continuous vocal stream.

Phoneme

The smallest unit of speech that can change the meaning of a word.

Categorical Perception

The phenomenon where phonemes are perceived as invariant within a specific range.

Broca’s Area

The brain region linked to speech production; damage results in Broca’s aphasia.

Wernicke’s Area

The brain region responsible for language comprehension; damage results in Wernicke’s aphasia.

Consonance

Notes that sound harmonious when played together.

Dissonance

Notes that sound unpleasant when played together.

Rhythm

The temporal relationship among sounds, specifically the duration of notes.

Melody

A sequence of sounds arranged in a pleasing pattern, combining pitch and rhythm.

Musician Stylistic Contributions

Techniques that enhance musical expression, including synchronization, articulation, and expressive tempo changes.

Formants

The narrow bands of sound frequency energy associated with vowels

Formant Transition

the transition from a broad energy spectrum to the narrow Formant spectrum. The transition per se appears to code for consonants

Manner of Articulation

refers to how the air stream is obstructed

Voicing

The timing and degree to which the vocal chords vibrate

Place of Articulation

where in the vocal tract the obstruction of the air stream occurs