Glossary Flashcards
Absolute Pitch (AP)
Also called perfect pitch, it is the rare (approximately 1:10,000) ability to accurately produce and identify a pitch chroma immediately, without the aid of an external or internal (e.g., long-term memory for an anchor pitch) reference.
Acoustic Reflex
An automatic nervous system response that contracts the ossicles of the middle ear, pulling them closer together to dampen vibrations at the oval window. The acoustic reflex minimizes hearing damage from high-intensity sound pressure waves with durations longer than 200ms or so.
Action Potential
The electrical signal conducted along neural axons or muscle fibers by which information is conveyed from one place to another in the nervous system.
Active Process
In cognitive psychology, referring to a process that requires attention, conscious participation, or a source of additional energy; cf. passive.
Adaptation
In psychometrics, adaptation refers to the tendency for sensory organs to adjust to the intensity or quality of stimulation. Good examples are the eyes adapting to the level of light or nose adapting to the smell in a room.
ADSR
This initialism refers to Attack, Decay, Sustain, and Release — the four primary characteristics of a sound wave’s envelope.
Afferent
An axon that conducts action potentials from the periphery toward the central nervous system.
Amplitude
The intensity of a pressure wave or electrical signal, it is measured on the y-axis graphically.
Amplitude Modulation
Amplitude modulation can refer to a technique whereby one frequency (the carrier, or fc) is combined with a much lower frequency, the modulator (fm). Amplitude modulation is used in radio broadcasting. Amplitude modulation also refers to the result of two waves with slightly different frequency (f1 and f2) combining in and out of phase, and the resultant wave rising and falling in amplitude at a frequency equal to f2 – f1. If the difference frequency is between 2 and 15 Hz, it is perceived as beating. If it is between 15 and 200 Hz, it is perceived as roughness.
Amplitude-Normalize
Loss or impairment of the ability to produce or comprehend music or musical tones. Amusia appears mainly as a deficit in pitch processing but musical memory and melody recognition are also impaired.
Analytic Listening
In music, the tendency to focus on the local details of individual pitches, chords, harmonies, timbres, and other components of a musical signal.
Anterior
Towards the front of an animal or structure. Anterior may be used as a synonym for rostral or ventral.
Aperiodic
A waveform or event that does not repeat in form or is irregular. Aperiodic sounds are not perceived as having pitch.
Apex
The top or highest part of something. In auditory science it is used to refer to the distal or far end of the basilar membrane where low frequency waves reach their peak.
Aphasia
The loss of ability to speak or understand speech caused by brain damage. Aphasia is different from aphonia which is the loss of speech due to mechanical damage in the throat.
Arcuate Fasciculus
A connective axonal tract in the temporal lobes linking regions important for speech (Broca’s area) and language (Wernicke’s area) processing.
Auditory Brainstem Response (ABR)
An electrical potential in the auditory nerve bundle from cochlear nuclei to the thalamus that is evoked by an auditory stimulus. The ABR occurs within milliseconds of stimulus onset and is measured by sensitive electrodes placed on the scalp, forehead, and/or below the ear.
Auditory Feedback
In signal processing, the return of a portion of the output signal to the input of a processing stage. Feedback is useful in controlling the output intensity of a gain stage. In behavioral tasks, auditory feedback refers to the capacity to hear one’s own performance.
Auditory Filter (also Cochlear Filter)
One of an array of bandpass filters that exist behaviorally in the peripheral auditory system, starting with the basilar membrane. Filter bandwidths are determined empirically by masking experiments.
Auditory Nerve Bundle
The auditory (or cochlear) nerve bundle is one half of the vestibulocochlear nerve, labeled cranial nerve VIII. It refers to the nerves that carry sensory information from the cochlea to the primary auditory cortex.
Auditory Pathway
Neural structures serving the auditory system from the inner ears to the primary auditory cortex in the temporal lobes.
Auditory Scene Analysis
The process by which the human auditory system organizes the sensation of sound waves into perceptually meaningful elements.
Autocorrelation
The correlation of a signal with a delayed copy of itself as a function of delay, or the similarity between observations as a function of the time lag between them. Autocorrelation is a mathematical tool for finding repeating patterns, such as the presence of a periodic
signal obscured by noise, or identifying the missing fundamental frequency in a signal implied by its harmonic frequencies.
A-Weighting
The most commonly used in a family of curves relating to the measurement of sound pressure level. It takes into account the fact that human listeners are less sensitive to low- frequency sounds. It is commonly used to measure low intensity sounds. Measurements using A-weightings are expressed in dB(A). B- and C-weightings are flatter and used to measure moderate and high-intensity sources.