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(A - C) (D - G) (H - L) (M - Q) (R - U) (V - Z)

A - C

Absolute pitch (07)

The ability to identify the pitch of any tone without the aid of a reference.

Absolute temperature (03)

The temperature (in Kelvins) on a scale that has its zero at the lowest attainable temperature (-273°)C; absolute temperature is found by adding 273 to the Celsius temperature.

Acceleration (01)

The rate of change of speed or velocity.

Accelerometer (30)

A device used to measure vibration; its electrical output indicates its acceleration (see Section 1.6).

Acoustic compiler (29)

A general-purpose computer program such as MUSIC V that translates a description of a sound written in a special language into the corresponding digital sound signal.

Acoustic feedback (24)

Sound from a loudspeaker picked up by a microphone (either in the direct field or the reverberant field) and re-amplified.

Acoustic illusion (29)

Y analogy to an optical illusion, a sound-typically synthetic-that "fools the ear into believing it is hearing something impossible or contradictory (such as a pitch that rises and falls simultaneously).

Acoustic impedance(04)

A measure of the difficulty of generating flow (in a tube, for example); it is the ration of the sound pressure to the volume velocity due to the sound wave.

Acoustic impedance(11)

The ratio of sound pressure to volume velocity. A graph of acoustic impedance of a musical instrument as a function of frequency shows peaks that correspond to the resonances of the air column.

Acoustics reflex (06)

Muscular action that reduces the sensitivity of the ear when a loud sound occurs.

ADAT (22)

Digital multi-track recording system that uses S-VHS video cassettes.

Additive synthesis (26)

Sound synthesis based on adding together many simple waveforms, such as sine waves at various frequencies, amplitudes, and phase offsets.

Additive synthesis (29)

The process of synthesizing sounds by adding together many simple components, such as sinusoids, each with typically time varying characteristics.

ADSR envelope generator (27)

A, D, S, and R refer to the parameters of an envelope: A = attack time; D = (initial) decay time; S = sustain level; R = (final) release time.

Aerodynamic (12)

Having to do with the flow of air and its interaction with other bodies.

Aerodynamic (32)

Having to do with the flow of air and its interaction with objects in its path.

Aerodynamic noise (30)

Noise generated by moving air or by the flow of air around a moving body (such as an automobile or truck).

Aftersound (14)

Second portion of a sound decay having a longer decay time.

Air-suspension speaker (19)

A loudspeaker mounted in the front of an airtight box so that the pressure of the enclosed air furnishes a major part of the force that restores the speaker cone to its equilibrium position.

Algorithm (26)

Any step-by-step instructions that solve a particular problem, such as the algorithm for performing long division.

Aliasing (21)

In a digital signal, the misrepresentation of frequencies above half the sampling rate at incorrect frequencies below half the sampling rate.

All-pass filter (24)

A filter with a constant ("flat) gain at all frequencies but with frequency-dependent phase shift.

All-pole filter (29)

A digital filter that uses feedback to create resonances but does not use anti-resonances (see Section 28.26).

Alternating current (ac) (18)

Electric current that reverses its direction of flow several times each second (120 times each second, in the case of electrical power distributed in the United States have a frequency of 60 Hz).

Ambience (25)

Spaciousness; the degree to which sound appears to come from many directions.

Ambience (25)

Spaciousness; the degree to which sound appears to come from many directions.

Amplifier (18)

A device in which a small amount of input power controls a larger amount of output power.

Amplitude (03)

The maximum displacement from equilibrium in a wave or vibrating system.

Amplitude (02)

Maximum displacement from rest.

Amplitude (04)

The height of the wave; the maximum displacement of a vibrating system from equilibrium.

Amplitude envelope (27)

The manner in which peak or average amplitude varies with time; the envelope is comprised of the attack and decay of a tone, among other things.

Analog electronics (26)

Electronic circuits in which the active elements (vacuum tubes and/or transistors) operate in their linear mode, i.e., as in amplifiers.

Analog-to-digital converter (ADC) (21)

A circuit that converts signals from an analog to a digital representation.

Analog-to-digital converter (ADC) (24)

A circuit that converts (analog) voltages to a digital or numerical representation.

Analog-to-digital converter (ADC) (26)

A circuit that converts information-typically a waveform representing a sound from analog representation (such as voltage versus time) to digital form (such as a sequence of binary numbers representing the waveform).

Analytic listening (07)

Listening to a complex tone in a way that individual components or partial tones are heard as separate entities.

Anechoic (03)

Echo free; an anechoic room is one whose walls, ceiling, and floor are covered with sound-absorbing material, usually in the shape of wedges.

Anechoic (23)

Echo-free; a tern applied to a specially designed room with highly absorbing wails.

Anisotropy (10)

The difference in some property when measured in different directions (such as the stiffness of wood along and across the grain).

Anode (26)

The positive (+) terminal in an electrical device such as a battery or vacuum tube.

Arithmetic/logic unit (ALU) (21)

A circuit within the central processing unit that performs arithmetic and logic operations.

Articulation index (AI) (31)

A means of rating speech interference by noise that considers the average speech level and average noise in each of 20 bands over the frequency range 250-7000 Hz.

Articulation loss of consonants (% AL) (24)

A measure of speech intelligibility; the percentage of consonants heard incorrectly (strongly influenced by noise or excessive reverberation).

ASCII (21)

American Standard Code for Information Interchange, which assigns 8-bit codes to commonly used symbols on an English computer keyboard.

Assembler (21)

A computer program that translates symbolic written codes into internal computer (machine) instructions on a more or less one-to-one basis.

Audiogram (31)

A graph of a person's hearing threshold at several frequencies compared to thresholds for normal hearing.

Audiometer (31)

An instrument that measures hearing thresholds of an individual at several audible frequencies.

Audion (26)

De Forest's first three-element vacuum tube (also known as a triode), consisting of a cathode, an anode, and a grid in between.

Auditory canal (05)

A tube in the outer ear that transmits sound from the external pinna to the eardrum.

Auditory fatigue (06)

Change in loudness of a sound that follows a loud sound.

Aural harmonic (08)

A harmonic that is generated in the auditory system.

Autocorrelation (08)

The comparison of a signal with a previous signal in order to pick out repetitive features.

Axon (08)

The part of a neuron or nerve cell that transmits neural pulses to other neurons.

Baffle (19)

An arrangement that reduces interference between sound radiated from the front and rear of a speaker by increasing the path length from front to back.

Band limited signal (28)

An analog signal that has no frequencies higher than a known given frequency.

Band limiter signal (21)

An analog signal that has no frequencies higher than a known given frequency.

Bark (07)

An interval of frequency equal to a critical bandwidth.

Base, collector, emitter (18)

The three regions of a transistor; in the most common usage, the input signal is applied to the base, and the output is taken from the collector.

Basilar membrane (05)

A membrane in the cochlea that separates the cochlear duct from the scala tympani and to which the organ of Corti is attached.

Bass bar (10)

The wood strip that stiffens the top plate of a violin or other string instrument and distributes the vibrations of the bridge up and down the plate.

Bass traps (25)

A tuned absorber used to absorb low frequencies in a room.

Bass-reflex enclosure (19)

A speaker enclosure in which the back wave from the speaker is radiated through a port or duct in the front.

Beats (08)

Periodic variations in amplitude that result from the superposition or addition of two tones with nearly the same frequency.

Bell (11)

The flared section that terminates all brass instruments and determines their radiation characteristics.

Belly (10)

The top plate of a violin.

Belting (17)

A manner of loud singing used by female popular singers to extend their chest register above its normal range.

Bernoulli effect (11)

The pressure in a fluid is decreased when the flow velocity is increased.

Bessel functions (29)

One of a class of transcendental functions named for nineteenth century Prussian astronomer Friedrich W. Bessel that solve a particular differential equation. Bessel functions occur in many contexts, including in the theory of FM music synthesis.

Bessel horn (12)

A family of horns of different shapes, including cylindrical and conical.

Bias (22)

That which is added to the desired signal to produce a composite. In the case of magnetic tape recording, for example, the bias is generally a constant magnetic field that oscillates at a high frequency.

Binary logic (26)

Any system of logic in which all properly formed statements are either TRUE or FALSE.

Binary number (21)

A number in base 2 representation; a 1 or a 0.

Binary number (26)

A base 2 number in which the digits are limited to either zero (0) or one (1).

Binary point (21)

In base 2 (binary) arithmetic, a period symbol used to denote the boundary between whole units.

Binaural (25)

Sound reproduction using two microphones (usually in a "dummy head) feeding two headphones, so that the listener hears the sound he or she would have heard at the recording location.

Bit (21)

A binary digit, used in the sense of a minimum unit of computer memory as well as small, two-valued unit of information.

Bit (26)

A contraction of the words binary digit; one bit is a single 1 or 0 and is either a basic unit of digital memory or a basic unit of information.

Bridge (10)

The wood piece that transmits string vibrations to the sound board or top plate.

Bus (21)

A group of wires connecting the CPU with the memory and I/O (in/out).

Byte (21)

An ordered collection of 8 bits of memory.

Capacitor (18)

A device that stores energy by creating an electrical field between two conductors; ac can flow through a capacitor but dc cannot.

Cardinal vowel (15)

Eight vowel sounds that serve as a standard of comparison for the vowels of various languages.

Cardioid microphone (25)

A microphone with a heart-shaped directivity pattern designed to pick up sound in one direction preferentially.

Cathode (26)

The negative (-) terminal in an electrical device such as a battery or vacuum tube.

CD-R (22)

A recordable compact disc that can be recorded once but played back many times.

CD-RW (22)

A recordable and erasable compact disc on which you can read and write.

Cent (09)

1/100 of a semitone.

Central processing unit (CPU) (21)

The portion of the computer that performs arithmetic, logic, and program sequencing operations.

Chest (modal) voice (17)

Mode of singing associated with a heavy mechanism or active vocalis muscles.

Chiff (14)

A chirp-like sound that occurs during attack, especially in flue pipes on an organ.

Chladni patterns (10)

A means for studying vibrational modes of a plate by making nodal lines visible with powder.

Chromatic scale (09)

An ascending or descending sequence of twelve tones, each separated by a semitone.

Clavichord (14)

A small portable instrument that produces a soft, delicate sound by means of struck strings.

Coarticulation (16)

Modification of speech sounds when they are connected to other sounds in a spoken sequence.

Cochlea (05)

The spiral organ of the inner ear containing the sound-sensing mechanism.

Codec (21)

A hardware or software device capable of both encoding and decoding digital signals.

Coercivity (22)

The magnetic field that must be applied in the reverse direction to reduce the magnetization to zero.

Comb filter (24)

A filter with amplitude minima regularly spaced in frequency.

Comb filters (25)

Filters that reject regularly spaced frequencies through interference.

Combination tone (08)

A secondary tone heard when two primary tones are received. Combination tones are usually difference tones.

Compact Disc Digital Audio (CD) (22)

An efficient means for digital sound recording that uses an optical pickup to read the recorded information.

Compander (21)

A device capable of both compressing and expanding the dynamic range of a signal.

Compensation (string) (10)

An extra length of string added because tension changes when a string is pressed against a fret.

Compiler (21)

A computer program that translates statements written in a high-level language (such as C or Pascal) into either low-level symbolic assembler code or directly into internal computer (machine) instructions.

Compliance (19)

A measure of flexibility; it is expressed in units of distance divided by force (m/N or cm/dyne).

Computer music (29)

The field of inquiry surrounding the application of computers and related technology to the synthesis, processing, and analysis of musical scores and sounds.

Concatenative synthesis (16)

Uses an inventory of natural speech pieces as building blocks from which an arbitrary utterance can be constructed.

Consonance (08)

Tones presented together with a minimum of roughness (opposite of dissonance).

Control room (25)

The important part of a recording studio in which the mixing, processing, and recording equipment, and listening monitors are located.

Convolution (28)

A process for combining two functions, consisting of replacing each instant in one function with a scaled copy of the other function.

Convolution (29)

A way of combining two mathematical functions that substitutes the entirety of one function for each point of the other function. Convolution occurs in many contexts, including the theory of waveforms and spectra as well as digital filtering.

Coordinates (01)

A set of numbers used to locate a point along a line or space.

Cricoarytenoids (17)

The muscles of the larynx that help to apply tension to the vocal folds.

Cricoid (17)

Lower cartilage of the larynx.

Cricothyroids (17)

The muscles of the larynx that determine the relative position of cricoid and thyroid cartilages and thus affect the vocal fold tension.

Critical band (05)

Frequency band within which two or more tones excite many of the same hair cells on the basilar membrane and thus are difficult to distinguish as separate tones.

Critical band (07)

The frequency bandwidth at which subjective response (to loudness, pitch, etc.) changes rather abruptly.

Critical band (08)

The range of frequencies over which tones simply add in loudness; the critical bandwidth appears to determine consonance or dissonance.

Critical bandwidth (06)

The frequency bandwidth beyond which subjective loudness increases with bandwidth.

Critical frequency (32)

The frequency of bending (flexural) waves in a panel that can be excited by sound waves traveling at the same speed.

Cross-correlation (08)

The comparison of two signals to pick out common features.

Crossover network (19)

A network designed to send high frequencies to the tweeter and low frequencies to the woofer. The crossover frequency is the appropriate point of division between high and low frequencies determined by the values of components in the circuit.

Cues (16)

Characteristics of speech sounds that help us to recognize them.

Current (18)

The flow of electrical charge. Current is measured in Amperes.

Current gain (18)

The ratio of output current to input current.

Cutoff frequency (11)

The frequency above which an instrument radiates so efficiently that standing waves inside the instrument are weak. In brass instruments the cutoff frequency is determined mainly by the shape of the bell.

Cutoff frequency (12)

The frequency above which the sound loss due to radiation through a lattice of tone holes is large, so that the resonances of an air column are weak.

Cut-up (14)

Height of the mouth opening in an organ pipe; distance from the lower lip to the upper lip.

(A - C) (D - G) (H - L) (M - Q) (R - U) (V - Z)

Copyright 2008, by the Contributing Authors. Cite/attribute Resource . admin. (2005, January 25). Glossary. Retrieved January 07, 2011, from Free Online Course Materials — USU OpenCourseWare Web site: http://ocw.usu.edu/Electrical_and_Computer_Engineering/Science_of_Sound/Glossary_5.htm. This work is licensed under a Creative Commons License Creative Commons License