找了这么多解释，也没见到SYNC的解释
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S
70 volt line See: constant-voltage
sabin A non-metric unit of sound absorption used in acoustical engineering. One sabin is the sound absorption of one square foot (or one square meter -- a metric sabin) of a perfectly absorbing surface--such as an open window. The sound absorption of a wall or some other surface is the area of the surface, in square feet, multiplied by a coefficient that depends on the material of the surface and on the frequency of the sound. These coefficients are carefully measured and tabulated. The unit honors Wallace Sabine (see below). Sabine used this unit, which he called the open window unit (owu), as early as 1911. [From Rowlett's How Many? A Dictionary of Units of Measurement]
Sabine, Wallace Clement Ware (1868-1919) American physicist and Harvard University professor who founded the systematic study of acoustics around 1895. Regarded as the father of the science of architectural acoustics.
SACD® (Super Audio CD®) Also known as DSD® or Direct Stream Digital®, joint trademark of Sony and Philips for their proposal for the next generation CD-standard. Sony and Philips have split from the DVD ranks to jointly propose their own solution comprised of a 1-bit, 64-times oversampled direct-stream digital SACD format. The original SACD proposal was for a hybrid disc comprising two layers: a high density (HD) DSD layer in the middle, and a standard density CD layer at the bottom. The two layers are read from the same side of the disc; the CD laser reads the bottom reflective layer through the semi-transmissive HD layer, while the middle layer is read by the HD laser delivering high-quality, multichannel sound without sacrificing backward compatibility. The HD layer has three tracks: the innermost is for two-channel stereo; the middle is a six-channel mix; and the outer is for such additional information as liner notes, still images and video clips. Maximum playing time is 74 minutes. This proposal turned out to be too expensive, so the SACD first release is a single-layer SACD-only disc.
SAE (Society of Automotive Engineers) The international trade organization comprised of 80,000 engineers, business executives, educators, and students representing 100 countries that functions as the resource for technical information and expertise used in designing, building, maintaining, and operating self-propelled vehicles for use on land or sea, in air or space.
sample rate conversion The process of converting one sample rate to another, e.g. 44.1 kHz to 48 kHz. Necessary for the communication and synchronization of dissimilar digital audio devices, e.g., digital tape machines to CD mastering machines.
sample-and-hold (S/H) A circuit that captures and holds an analog signal for a finite period. The input S/H proceeds the A/D converter, allowing time for conversion. The output S/H follows the D/A converter, smoothing glitches.
Sampling (Nyquist)Theorem A theorem stating that a bandlimited continuous waveform may be represented by a series of discrete samples if the sampling frequency is at least twice the highest frequency contained in the waveform.
sampling frequency or sampling rate The frequency or rate at which an analog signal is sampled or converted into digital data. Expressed in Hertz (cycles per second). For example, compact disc sampling rate is 44,100 samples per second or 44.1 kHz, however in pro audio other rates exist: common examples being 32kHz, 48kHz, and 50kHz. [Historical note re 44.1kHz vs. 44.056kHz: Since the first commercial digital audio recorders used a standard helical scan video recorder for storage, there had to be a fixed relationship between sampling frequency and horizontal video frequency, so these frequencies could be derived from the same master clock by frequency division. For the NTSC 525-line TV system, a sampling frequency of 44,055.94 Hz was selected, whereas for the PAL 625-line system, a frequency of 44,100 Hz was chosen. The 0.1% difference shows up as an imperceptible pitch shift.]
sampling The process of representing the amplitude of a signal at a particular point in time.
SAN (storage area network) A network connecting host computers to storage servers and systems. SAN technology allows high-speed connection of multiple workstations to a centralized hard-disk network (via fiber optics interconnection), allowing each workstation to access any drive from any location (e.g., control rooms in DAW recording studios).
SAR (successive approximation register) A type of analog-to-digital converter using a digital-to-analog converter to determine the output word successively, bit by bit.
sawtooth wave A periodic waveform characterized by a 50% duty cycle and a Fourier series consisting of both even- and odd-ordered, equal phase, sinisoidal harmonic components of its fundamental frequency. The amplitudes (coefficients multiplying the magnitude of the fundamental sine wave) of the odd-ordered harmonics are the same as a square wave, while the amplitudes (re the fundamental) for the even-ordered harmonics are -1/n, where n is the even harmonic number. Therefore the first few even harmonic multipliers are -1/2, -1/4, -1/6, ... etc., and the first few odd harmonic multipliers are 1/3, 1/5, 1/7, ... etc.
Schottky, Walter (1886-1976) German physicsts whose work in solid-state physics and electronics resulted in many inventions that bear his name (Schottky effect, Schottky barrier, Schottky diode). He also invented the tetrode and (with Erwin Gerlach) the ribbon microphone and ribbon tweeter.
SCMS (pronounced "scums") (serial copy management system) The copy protection scheme applied to consumer digital recording equipment - it does not apply to professional machines. This standard allows unlimited analog-to-digital copies, but only one digital-to-digital copy. This is done by two control bits (the C and L bits) contained within the digital audio data.
screeched The longest one-syllable word in the English language.
SCSI port (pronounced "scuzzy") (small computer system interface) A standard 8-bit parallel interface used to connect up to seven peripherals, such as connecting a CD-ROM player or document scanner to a microcomputer.
SD (super density compact disc) See: DVD
SDDS® (Sony Dynamic Digital Sound) Sony's competing format for the digital soundtrack system for motion picture playback. The signal is optically printed outside the sprocket holes, along both sides of the print. Sony recently developed a single camera system that records all three digital formats (Dolby Digital, DTS & SDDS) on a single inventory print, thus setting the stage for long term coexistence of all formats.
SDIF (Sony digital interface format) Sony's professional digital audio interface utilizing two BNC-type connectors, one for each audio channel, and a separate BNC-type connector for word synchronization, common to both channels. All interconnection is done using unbalanced 75 ohm coaxial cable of the exact same length (to preserve synchronization), and is not intended for long distances.
SDMI (Secure Digital Music Initiative) A multi-industry group defining a specification to protect digital music distribution.
self-noise Microphones. Residual noise, or the inherent noise level of a microphone when no signal is present. Microphone inherent self-noise is usually specified as the equivalent SPL level which would give the same output voltage, with typical values being 15-20 dB SPL.
SEMA (Specialty Equipment Market Association ) An organization for the producers and marketers of specialty equipment products and services for the automotive aftermarket. Today's group grew out of the original SEMA started in 1963, known then as the "Speed Equipment Manufacturers Association" and includes aftermarket audio manufacturers.
semitone Music. An interval equal to a half tone in the standard diatonic scale. Also called half step, half tone. (AHD)
sensitivity 1. Audio electromechanics. The standard way to rate audio devices like microphones, headphones and loudspeakers. A standard input value is applied and the resultant output is measured and stated. Loudspeaker sensitivity: the standard is to apply one watt and measure the sound pressure level (SPL) at a distance of one meter. Headphone sensitivity: the standard is to apply one milliwatt and then measure the sound pressure level at the earpiece (using a dummy head with built-in microphones). Microphone sensitivity: the standard is to apply a 1 kHz sound source equal to 94 dB SPL (one pascal) and then measure the output level and express it in mV/PA (millivolts per pascal). 2. Audio electronics. The minimum input signal required to produce a standard output level. Power Amplifier sensitivity: The input level required to produce one watt output into a specified load impedance, usually 4 or 8 ohms. Radio receiver sensitivity: The input level required to produce a specified signal-to-noise ratio. Et cetera.
serial interface A connection which allows transmission of only one bit at a time. An example in the PC world is a RS-232 port, primarily used for modems and mice. A serial interface transmits each bit in a word in sequence over one communication link. See also: parallel interface.
serializer A parallel-to-serial data converter; used in buses and networks.
server A shared master computer on a local area network (LAN) used to store files and distribute them to clients upon demand.
servo-loop; servo-locked loop; servo-mechanism A self-regulating feedback system or mechanism. Typically a feedback system consisting of a sensing element, an amplifier, and a (servo)motor, used in the automatic control of a mechanical device (such as a loudspeaker). In audio, usually the name applies to a class of electronic control circuits comprised of an amplifier and a feedback path from the output signal that is compared with a reference signal. This topology creates an error signal that is the difference between the reference and the output signal. The error signal causes the output to do whatever is necessary to reduce the error to zero. A loudspeaker system with motional feedback is such a system. A sensor is attached to the speaker cone and provides a feedback signal that is compared against the driving signal to create more accurate control of the loudspeaker. Another example is Rane's servo-locked limiter™ which is an audio peak limiter circuit where the output is compared against a reference signal (the threshold setting) creating an error signal that reduces the gain of the circuit until the error is zero.
servo-locked limiter™ Rane Corporation trademark for their proprietary limiter circuit. See: servo-loop
SFDR (spurious free dynamic range) A testing method used in quantifying high-speed data converters and high-frequency communication integrated circuits. It is the difference in dB between the desired output signal and any undesired harmonics found in the output spectrum. See Intersil Application Note TB326 for measuring details.
Shannon, Claude E. (1916-2001) American mathematician and physicist who is credited as the father of information theory (For the mathematically advanced, see his famous paper, "A Mathematical Theory of Communication" published in 1948 in The Bell ) . In his master's thesis Shannon showed how an algebra invented by the British mathematician, George Boole in the mid-1800s could represent the workings of switches and relays in electronic circuits. His paper has been called "possibly the most important master's thesis in the century."
shaped triangular See TPDF
shelving response Term used to describe a flat (or shelf) end-band shape when applied to program equalization. Also known as bass and treble tone control responses.
show control See MIDI show control.
SI (International System of Units) The International System of Units, universally abbreviated SI (from the French Le Système International d'Unités), is the modern metric system of measurement. SI is the dominant measurement system not only in science, but also in international commerce. See link for a downloadable copy of Barry N. Taylor's Guide for the Use of the International System of Units (SI). This free 86 page document is the definitive source of SI info.
sibilant Linguistics. adj. Of, characterized by, or producing a hissing sound like that of (s) or (sh): the sibilant consonants; a sibilant bird call. A sibilant speech sound, such as English (s), (sh), (z), or (zh). (AHD)
SID (slew-induced distortion) See: DIM/TIM
side-chain In a signal processing circuit, such as one employing a VCA, a secondary signal path in parallel with the main signal path in which the condition or parameter of an audio signal that will cause a processor to begin working is sensed or detected. Typical applications use the side-chain information to control the gain of a VCA. The circuit may detect level or frequency or both. Devices utilizing side-chains for control generally fall into the classification of dynamic controllers.
sidetone Telephony. The feature of a telephone handset that allows you to hear yourself talk, acting as feedback that the phone is really working. Sidetones are actually short line echoes bled back into the earpiece. Too much sidetone sounds like an echo and too little sounds so quiet that people think the phone is broken. Sidetones are good for people but can cause acoustic feedback in teleconferencing systems if not treated properly.
sigma-delta See: delta-sigma modulation
signal levels Audio signal levels: see levels.
signal present indicator or SIG PRES An indicator found on pro audio signal processing units that lights once the input signal level exceeds a preset point. There is no standard specifying when a SIG PRES light should illuminate, although common practice makes it -20 dBu (77.5 mV), or the pro audio de facto standard line-level of +4 dBu (1.23 volts).
signal-to-noise ratio See: S/N
SIL (speech interference level) The numerical part of the RC noise rating.
Silicon Dust™ Nickname for microchips. Trademarked name first coined by National Semiconductor to describe the world's smallest op amp (as of May 5, 1999), the LMV921. Used in surface mount technology (SMT), they are about the size of a single letter on this page.
silver One of the English language words without a rhyme -- others are "month," "orange" & "purple."
SINAD (pronounced "sin-add") or S/N+D (signal-to-noise and distortion) Acronym for the ratio: (signal + noise + distortion) / (noise + distortion). Or, as Metzler explains, it is the reciprocal of THD+N stated in decibels (dB). Originally developed for measuring FM receivers, it now also appears on A/D data sheets. Generally, the term "SINAD" is favored by the communication industry, while "S/N+D" is used by the audio industry, but they both mean the same thing. It is the preferred way to specify the dynamic range, or maximum S/N, since the noise and distortion products are measured in the presence of a signal. [A signal is applied to the input, the output is passed through a notch filter to remove the signal and what remains is measured. Then the ratio of the rms value of the measured output signal to the rms value of everything else coming out (i.e., noise + distortion) is expressed in decibels.] This gives a more accurate picture of real dynamic performance. Sometimes the measurement is stated for three reference levels of 0 dBFS, -20 dBFS, and -60 dBFS.
sine Abbr. sin Mathematics. 1. The ordinate of the endpoint of an arc of a unit circle centered at the origin of a Cartesian coordinate system, the arc being of length x and measured counterclockwise from the point (1, 0) if x is positive or clockwise if x is negative. 2. In a right triangle, the ratio of the length of the side opposite an acute angle to the length of the hypotenuse. (AHD)
sine curve Mathematics. The graph of the equation y = sin x. Also called sinusoid. (AHD)
sine wave Physics. A waveform with deviation that can be graphically expressed as the sine curve. (AHD)
sinusoid Mathematics. See: sine curve
skin effect 1. Electrical cable. The tendency of high frequency (RF and higher) current to be concentrated at the surface of the conductor. 2. Induction heating. Tendency of an alternating current to concentrate in the areas of lowest impedance.
slapback See slap echo below.
slap echo also called slapback 1. Acoustics. A single echo resulting from parallel non-absorbing (i.e., reflective) walls, characterized by lots of high frequency content. So-called because you can test for slap echo by sharply clapping your hands and listening for the characteristic sound of the echo in the mid-range. Slap echo smears a stereo soundfield by destroying the critcal phase relationships necessary to form an accurate sound stage. 2. Recording. Devices that simulate slap echo are popular in recording. One distinct repeat echo is added to an instrument sound resulting in a very live sound similar to what you would hear in an auditorium.
slew rate 1. The term used to define the maximum rate of change of an amplifier's output voltage with respect to its input voltage. In essence, slew rate is a measure of an amplifier's ability to follow its input signal. It is measured by applying a large amplitude step function (a signal starting at 0 volts and "instantaneously" jumping to some large level [without overshoot or ringing], creating a step-like look on an oscilloscope) to the amplifier under test and measuring the slope of the output waveform. For a "perfect" step input (i.e., one with a rise time at least 100 times faster than the amplifier under test), the output will not be vertical; it will exhibit a pronounced slope. The slope is caused by the amplifier having a finite amount of current available to charge and discharge its internal compensation capacitor. 2. Mathematics. Slew rate is defined to be the maximum derivative of the output voltage with respect to time. That is, it is a measure of the worst case delta change of voltage over a delta change in time, or the rate-of-change of the voltage vs. time. For sinusoidal signals (audio), this equals 2 pi times the maximum frequency, times the maximum peak output voltage: SR = (2 pi) (Fmax) (Vpeak).
smoke From the phlogiston theory of electronics, it is smoke that makes ICs and transistors work. The proof of this is self-evident because everytime you let the smoke out of an IC or transistor it stops working -- elementary. This has been verified through exhaustive testing, particularly regarding power amplifier ICs and transistors. (Incidentally, wires carry smoke from one device to another.) [Origin unknown but classic.]
smoothing filter See: anti-imaging filter
SMPTE (pronounced "simty") (Society of Motion Picture and Television Engineers) A professional engineering society that establishes standards, including a time code standard used for synchronization.
SMT (surface mounting technology) The science of attaching and interconnecting electronic devices, whose entire body projects in front of the mounting surface, as opposed to through-hole devices found on the earliest printed circuit boards. With surface mount technology all components sit on the surface of printed circuit boards and are soldered to conductive pads. With through-hole parts, component leaads are placed through holes in the boards and then solderered from the back side. SMT is more cost-effective and allows far greater density of parts.
S/N or SNR (signal-to-noise ratio) An audio measurement of the residual noise of a unit, stated as the ratio of signal level (or power) to noise level (or power), normally expressed in decibels. The "signal" reference level must be stated. Typically this is either the expected nominal operating level, say, +4 dBu for professional audio, or the maximum output level, usually around +20 dBu. The noise is measured using a true RMS type voltmeter over a specified bandwidth, and sometimes using weighting filters. All these thing must be stated for a S/N spec to have meaning. Simply saying a unit has a SNR of 90 dB means nothing, without giving the reference level, measurement bandwidth, and any weighting filers. A system's maximum S/N is called the dynamic range.
S/N+D or S/(N+D) See SINAD
SNMP (Simple Network Management Protocol) The most common method by which network management applications can query a management agent using a supported MIB (Management Information Base). SNMP operates at the OSI Application layer. The IP (Internet Protocol)-based SNMP is the basis of most network management software, to the extent that today the phrase "managed device" implies SNMP compliance.
snollygoster Defined in 1895 as "a fellow who wants office, regardless of party, platform or principles and who ... gets there by the sheer force of monumental talknophical assumancy". [McQuain, Never Enough Words]
soft clipping See: clipping
solo A term used in recording and live-sound mixing to describe monitoring (via headphones) a single channel without affecting the main outputs (see: PFL) -- same as cueing; however, it can also refer to certain console designs where it replaces the main mix with the soloed channel (called destructive solo).
sone A subjective unit of loudness, as perceived by a person with normal hearing, equal to the loudness of a pure tone having a frequency of 1,000 hertz at 40 decibels sound pressure level. (AHD)
sonorous 1. Having or producing sound. 2. Having or producing a full, deep, or rich sound. (AHD)
sound 1.a. Vibrations transmitted through an elastic material or a solid, liquid, or gas, with frequencies in the approximate range of 20 to 20,000 hertz, capable of being detected by human ears. Sound (in air) at a particular point is a rapid variation in the air pressure around a steady-state value (atmospheric pressure) - that is, sound is a disturbance in the surrounding medium. b. Transmitted vibrations of any frequency. c. The sensation stimulated in the ears by such vibrations in the air or other medium. d. Such sensations considered as a group. 2. Auditory material that is recorded, as for a movie. 3. Meaningless noise. 4. Music. A distinctive style, as of an orchestra or a singer. (AHD) See sound.
sound absorption See absorption.
sound off To express one's views vigorously: He was always sounding off about his boss. (AHD)
sound pressure The value of the rapid variation in air pressure due to a sound wave, measured in pascals, microbars, or dynes - all used interchangeable, but pascals is now the preferred term. Instantaneous sound pressure is the peak value of the air pressure, often used in noise control measurements. Effective sound pressure is the RMS value of the instantaneous sound pressure taken at a point over a period of time.
sound pressure level or SPL 1. The RMS sound pressure expressed in dB re 20 microPa (the lowest threshold of hearing for 1 kHz). [As points of reference, 0 dB-SPL equals the threshold of hearing, while 140 dB-SPL equals irreparable hearing damage.] See: inverse square law 2. Blue whales, the largest living animals, also make the loudest sounds by any living source. Their low-frequency pulses have been measured at 188 dB-SPL and detected 530 miles away according to The Guinness Book of World Records®.
Sound Recording History Fantastic site put together by David Morton.
SPARS (Society of Professional Audio Recording Services) Founded in 1979, a professional trade organization that unites the manufacturers of audio recording equipment and providers of services, with the users. Their goal is worldwide promotion of communication, education and service among all those who make and use recording equipment. Often confused with NARAS.
spatial Of, relating to, involving, or having the nature of space. (AHD)
Spatializer A single-ended spatial enhancement technique developed by Desper Products, Inc., a subsidiary of Spatializer Audio Labs, Inc. Widely licensed in both the consumer audio and multimedia computing markets, the Desper, or Spatializer process is normally used as a postprocessor. The Spatializer technology manipulates the original signal in a way that causes the listener to perceive a stereo image beyond the boundaries of the two loudspeakers. It claims to place sounds in front of the listener in an arc of 180 degrees, with excellent imaging and fidelity.
S/PDIF (Sony/Philips digital interface format, also seen w/o slash as SPDIF) A consumer version of the AES3 (old AES/EBU) digital audio interconnection standard based on coaxial cable and RCA connectors.
speech interference level (SIL) The numerical part of the RC noise rating.
Speakon® See connectors
spectra A plural of spectrum. In pro audio use, the distribution of frequency of a sound signal, especially: the distribution of sound energy, arranged in order of frequency wavelengths.
spell checker A software program used by word processors to tell you that the following truism has no spelling errors: "Dew knot trussed yore spell chequer two fined awl mistakes."
SPICE (simulation program with integrated circuit emphasis) A computer circuit analysis program first developed and written by L. W. Nagel and D. O. Pederson of the EECS (Electrical Engineering and Computer Sciences) Department of UC Berkeley¹. This was not the first simulation program by members of UC Berkeley's EECS Department. SPICE evolved from forerunners BIAS² and CANCER³. The SPICE program was used extensively for classroom instruction and graduate research. As such, each year it was refined and expanded by each new batch of graduate students (yes, even I worked on SPICE, developing op amp models during by graduate years at UC Berkeley) until it expanded beyond Berkeley's domain through licensing and the advent of mini and personal computers beginning in 1981. Indeed, PSPICE (Personal SPICE) developed in 1984 by Wolfram Blume (first doing business as Blume Engineering, then MicroSim, acquired by OrCAD, now owned by Cadence), the first version of SPICE for personal computers, is now the industry standard for circuit-simulation.
References
1. L.W. Nagel and D.O. Pederson, "Simulation Program with Integrated Circuit Emphasis (SPICE)," presented at the 16th Midwest Symposium on Circuit Theory, Waterloo, Ontario, April 12, 1973.
2. W.J. McCalla and W.G. Howard, Jr., "BIAS-3 -- A Program for the Nonlinear DC analysis of Bipolar Transistor Circuits," IEEE J. Solid-State Circuits, vol. SC-6, Feb. 1971, PP. 14-19.
3. L. Nagel and R. Rohrer, "Computer Analysis of Nonlinear Circuits, Excluding Radiation (CANCER)," IEEE J. Solid-State Circuits, vol. SC-6, Aug. 1971, pp. 166-182.
SPIF (sales promotion incentive fund) Same as no. 3 following.
spiff 1. To make attractive, stylish, or up-to-date: spiffed up the the old storefront. 2. Attractiveness or charm in appearance, dress, or manners: “He may need more than spiff to get him through the bad patches ahead ” James Wolcott [Possibly from dialectal spiff well-dressed] (AHD) 3. Giveaways (usually in the form of money) by manufacturers as added incentive ("make attractive") to personnel selling their goods. Compare with swag
spiral quad Same as star quad; see cables.
SPL controller See: leveler
SPL See: sound pressure level
splitter An audio device used to divide one input signal into two or more outputs. Typically this type of unit has one input with 6-16 (or more) outputs, each with a level control and often is unbalanced. See: distribution amplifier
spooler Comes from the acronym SPOOL derived from simultaneous peripheral operation on-line (also sequential peripheral operations on-line). A program or piece of hardware that controls a buffer of data going to some output device, including a printer or a screen. Spooling temporarily stores programs or program outputs on magnetic tape, RAM or disks for output or processing. (Newton) ... and you thought you were done learning for the day -- Ha!
SQ Columbia's (CBS - now Sony Music) name for their quadraphonic sound system using a proprietary matrixing algorithm for encoding four-channel sound down to two-channels. See Matrix Quad Compare with QS
SQNR (signal to quantization noise ratio A measure of the quality of the quantization, or digital conversion of an analog signal. Defined as normalized signal power divided by normalized quantization noise power. The SQNR in dB is approximately equal to 6 times the number of bits of the ADC, for example, the maximum SQNR for 16 bits is approximately 96 dB.
square wave A periodic waveform characterized by a 50% duty cycle and a Fourier series consisting of odd-ordered, equal phase, sinisoidal harmonic components of its fundamental frequency with amplitudes (coefficients multiplying the magnitude of the fundamental sine wave) equal to 1/n, where n equals the harmonic number. Therefore the first few harmonic amplitudes are 1/3, 1/5, 1/7, 1/9, etc. For a very cool pictorial, see Fourier Series: Square Wave Tool. And if you are missing the math, see Cuthbert Nyack's Fourier Series of Square Wave
SRS (Sound Retrieval System) A stereo image enhancement scheme invented by Arnold Klayman in the early '80s while working for Hughes Aircraft, and since 1993, marketed by SRS Labs, Inc. A standalone spatial enhancement scheme, SRS benefits from not requiring encoding of the signal, but thus prevents the audio producer from determining the location of individual sound effects. The results vary, being heavily dependent upon the original stereo mix. The goal is to extend the sound field well beyond the limitations of the loudspeakers, and make the overall sound seem more expansive. The elimination of the sweet spot is claimed.
standing wave See room mode.
star quad mic cable See cables.
Star-Spangled Banner The flag of the United States.
star topology 1. A set of three or more branches with one terminal of each connected at a common node. 2. A communications network based on a star pattern where all equipment is connected to a central location with a single path.
star-wired ring See token ring.
steganography The science of communicating in a way that hides the existence of the actual communication. The practice of hiding information in a wider bandwidth carrier. This field covers the techniques used in digital watermarking schemes.
stereo or stereophonic sound Term applied to any system of recording (or transmission) using multiple microphones for capturing and multiple loudspeakers for reproduction the sound. Stereo as the term has become popularly used restricts the number of playback loudspeakers to two, but strictly speaking the term can apply to any number of loudspeakers. Although stereo was first demonstrated at the Paris Opera in 1881 (really) using carbon microphones and earphones, it would not become widespread until the work of Blumlein in the 1930s.
stereo 2-way or stereo 3-way, etc. See: active crossover
stewardesses Longest English word typed using only the left hand.
stiction Physics. In positioning, the friction that prevents immediate motion when force is first applied to a body or surface at rest.
stopband The range of frequencies substantially attenuated by a filter as opposed to the range of frequences unaffected by the filter. The opposite of passband.
STP (shielded twisted-pair) See cables; also Scientifically Treated Petroleum, but that's another time and another story.
streaming media Internet. A process in which audio, video, and other multimedia is delivered “just in time” over the Internet or company intranet. Pioneered and named by Netscape, as a smarter way to deliver data, their browser immediately loaded text and then followed with graphics in real time as it arrived (streamed in), then RealNetworks came along and applied this technology to audio and video.
structured audio See MPEG-4
subcode Non-audio digital data encoded on a CD that contains definable information such as track number, times, copy inhibit, copyright, etc.
subgroups See: groups
submix See: groups
subsonic Having a speed less than that of sound in a designated medium. (AHD) [Use infrasonic if referring to frequencies below human hearing range.]
subtend 1. Mathematics. To be opposite to and delimit: The side of a triangle subtends the opposite angle. 2. To underlie so as to enclose or surround: flowers subtended by leafy bracts.(AHD)
supersonic Having, caused by, or relating to a speed greater than the speed of sound in a given medium, especially air. (AHD) [Use ultrasonic if referring to frequencies above human hearing range.]
suppression also gain suppression In teleconferencing the term used to describe the technique of instantaneous reduction of a sound system's overall gain to control acoustic feedback, and thus reduce echoes.
S-video Also called Y/C video, a two-channel video channel that transmits black and white, or luminance (Y), and color portions, or chrominance (C), separately using multiple wires. This avoids composite video encoding, such as NTSC, thus providing better picture quality. Found mostly on S-VHS and Hi8 products, and some Laserdisc and DVD players.
swag 1. Slang Stolen property; loot. [According to Mercenary Audio: (pirate term) Stolen without a gun, but I can find no collaboration.] 2. Slang Herbal tea in a plastic sandwich bag sold as marijuana to an unsuspecting customer. 3. Australian To travel about with a pack or swag. (AHD) 4. Slang Acronym for scientific (or silly or sophisticated) wild ass guess. 5. Slang Giveaways (usually in the form of merchandise "loot") by manufacturers as added incentive to personnel either selling or buying their goods. Compare with spiff
sweet spot Any location in a two loudspeaker stereo playback system where the listener is positioned equidistant from each loudspeaker. The apex of all possible isosceles (two equal sides) triangles formed by the loudspeakers and the listener. In this sense, the sweet spot lies anywhere on the sweet plane extending forward from the midpoint between the speakers.
SWG (standard wire gauge) British or Imperial standard. See AWG.
symmetrical (reciprocal) response Term used to describe the comparative shapes of the boost/cut curves for variable equalizers. The cut curve exactly mirrors the boost curve.
synchronous A transmission process where the bit rate of the signal is fixed and synchronized to a master clock.
Syn-Aud-Con (Synergetic Audio Concepts) A private organization conducting audio seminars and workshops, sponsored by several pro audio companies.
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