SACD

Super Audio Compact Disc - is one of two main emerging new standards for high-resolution audio on compact discs. The other is DVD-Audio. It was developed by Sony and is based on a licensed technology called Direct Stream Digital, which was developed by Sony and Phillips and is theoretically capable of sample rates up to 2.8 MHz. The S A C D format allows for playback of multi-channel audio and a bandwidth of 100 kHz at over 120 dB dynamic range while retaining compatibility with existing compact disc technology. There are several subformats in the works (single layer, dual layer, etc.) that are optimized for different tasks, but Sony claims that all SACD discs have fully uncompromised audio quality. That is, no data compression, and no computer generated surround mixes from stereo data or vice versa. The potential success of this format in the mainstream is currently under scrutiny amidst other developments such as DVD Audio, but there are a number of titles available on the Sony label with promised support from other record labels.

Santoprene

A speaker surround material constructed of Santoprene (a manufactured rubber), offering improved resistance to stretching and deterioration over time compared to Butyl rubber.

SAT

Supervisory Audio Tone - In cellular applications, refers to the Supervisory Audio Tone.

Scanning

The popular term given to the process a thief uses to break into a remote security system by quickly and sequentially transmitting all the possible security codes of a victim's security system.

SCM

In cellular applications, refers to the Station Class Mark.

Sd

Piston area of a speaker.

Sealed Enclosure

A type of speaker enclosure with a specific internal volume of air to enhance the speaker's response.

Seat Position

A DSP parameter that correlates to the apparent location in a specific listening environment.

Seat Sensor

A pressure activated switch designed specifically for use in detecting any pressure applied to a vehicle's seat.

Second-Order

The frequency attenuation that occurs at a rate of 12 dB per octave.

Secondary

The output side of a transformer.

Segmented Display

An entry level display type that employs a number of elements which make up the display characters, e.g., digital clock display.

Selectivity

Tuner specification which defines the tuner's ability to reject adjacent station interference.

Sensitivity

A measurement of the sound output of a speaker or speaker system's output relative to the power put in. Typically measured in dB at 1 watt of input, 1 meter away.

Sensor

A device designed to detect or sense an intrusion or attack upon a vehicle by monitoring such things as motion, vibration, impact, sound, or the presence of a foreign mass.

Sensor Bypass

The ability of a security system to automatically or manually delete or bypass the triggers from all or some of the sensors tied into the security system.

Series-Parallel

A circuit where there are components wired in series and in parallel to get the desired result. This is often used in multi-woofer systems to optimize the impedance seen by an amplifier.

Series Sixth Order-Enclosure

An enclosure consisting of a vented box with its port firing into another vented box.

Series Wiring

A circuit where components are wired sequentially, dividing the voltage between them.

SFEQ Performance Chip

Allows independent control of bass and treble and for front and rear speakers, so music can be shaped to your vehicle's contours for improved sound quality.

Short Circuit

The condition that occurs when a circuit path is created between the positive and negative poles of a battery, power supply, or circuit. A short circuit will bypass any resistance in a circuit and cause it not to operate.

Shuffle Play

A feature which employs random selection from available tracks.

Signal-to Noise Ratio

A ratio which indicates how much audio signal there is in relation to noise, or a specified noise floor.

Silk Dome

Dome tweeters in which the dome is composed of a treated soft silk like material. This is a design that is much less susceptible to mechanical deformation, and yet yields a fairly smooth response over the extent of its range.

Simultaneous Stereo-Mono

The ability of an amplifier to drive three speakers from two channels, deriving either a subwoofer or center channel signal from the two other channels.

Sine Wave

The waveform of a pure alternating current or voltage. It deviates about a zero point to a positive value and a negative value. Audio signals are sine waves or combinations of sine waves. The waveform of a pure alternating current or voltage. It deviates about a zero point to a positive value and a negative value. Audio signals are sine waves or combinations of sine waves.

SLA

Source Level Adjuster - Allows you to independently adjust the volume ratio between all of the headunit sources (using the FM volume level as a reference (as this cannot be changed)), so the start-up volume of the various sources (ie. CD, Tape)will be the same.

Slew Rate

Slew rate measures the ability of a piece of audio equipment to accurately reproduce fast changes in amplitude. Measured in volts per microsecond, this spec is most commonly associated with amplifiers, but can bet applied to most types of equipment. In amplifiers, a low slew rate softens the definition of a signal, blurring transients and sounding "mushy." Slew rate is most critical in high frequencies reproduction where rapid changes in amplitude are most pronounced. An amplifier with a higher slew rate is often subjectively rated as tighter and more dynamic.

Slope

The rate of change that a frequency response curve displays, normally stated in dB per Octave. Among other things, Slope can relate to Roll Off rates in Crossover action, low-end roll off and roll on rates and other forms of increasing or decreasing response.

Sound

A type of physical kinetic energy called acoustical energy (Also see Acoustical Energy) generally accepted to be between 20 and 20,000 cycles per second.

Soundstage

The position (front/back and high/low) that music or sound appears to be originating from, as well as the apparent depth of the stage. A car with speakers only in the front will likely have a forward soundstage, but may not have enough rear fill to make the music seem live. A car with both front and rear speakers may have anything from a forward to a rear soundstage, with an accompanying fill from the softer drivers depending on the relative power levels and the frequencies reproduced. The high/low position of the soundstage is generally only obvious in a car with a distinctly forward soundstage. The music may seem to be originating in the footwells, the dash, or out on the hood, depending on the car's design.

Sound Discriminator

A device designed to listen to, evaluate, and discriminate between the sounds that may be heard within the interior of a vehicle, and then trigger the security system should the sound fit within the parameters of what the sensor is designed to react.

Sound Pressure Level

Acoustic measurement for sound output. Measured in dB, the readings are often "weighted" to reflect how human ears work.

Sound Waves

Fluctuating waves of pressure that travel through a physical medium such as air. An acoustic wave consists of a traveling vibration of alternate compressions and rarefactions, whereby sound is transmitted through air or other media.

Source Impedance

A parameter of an audio component referring to the output impedance. A low output impedance is preferred.

Source Tone Memory

A Custom File feature which allows the user to assign a collection of tone control settings to a particular source, such that anytime that source is selected, those tone control settings are automatically recalled.

SPDT

Single Pole Double Throw - A relay that has only one pole or contact but whose contact can throw or make electrical contact with two separate stationary contacts. This is the most commonly used relay in the mobile electronics industry.

Spectrum Analyzer

A device that displays a frequency response curve, in real time, as the curve, changes.

Spider

A flat, round, springy device that holds the vibrating cone of a dynamic loudspeaker. The spider is where the diaphragm meets the voice coil.

SPL

Sound Pressure Level - An acoustic measurement for the ratios of sound energy. Rated in decibels (dBA).

Spontaneous Twin Drive

Amplifier power supply technology which employs separate voltage rails for different amplifier stages. This methods provides greater headroom and helps prevent clipping.

SPST

Single Pole Single Throw - A relay that has only one pole or contact and can only throw or make electrical contact with one stationary contact.

SSIR

Sony Super Interference Rejection - Sony's proprietary FM front end enabling both excellent sound quality and clear reception.

SSIR-EX

An improved version of the SSIR FM front end which offer better sensitivity, selectivity, capture ratio and stereo separation specifications.

Station Memo

A Custom File feature that allows the user to assign an eight character name to a tuner frequency.

Status

The state that a system is in at any given time.

Stray Field Containment Geometry

A speaker motor assembly designed to reduce stray magnetic fields around the speaker and focus the energy in the voice coil gap. Proprietary to JBL, this method is used in high-end products such as the GTi competition series.

Stroke-Audio

The distance that the speaker cone or voice coil can travel in both directions.

Strontium Magnet

A magnetic material with superior magnetic strength characteristics to that of ferrite.

Subwoofer

A loudspeaker made specifically to reproduce the lowest of audio frequencies, approximately between 45 Hz and 125 Hz .Generally used only below 80Hz.

Subwoofer Preamp Outputs

Individual number of RCA outputs that are coupled with a built-in low-pass crossover for connection to a dedicated subwoofer amplifier.

Sub Output

A separate output connection specifically designed to drive a sub woofer system.

Supertuner III

Pioneer's tuner technology that features strong resistance to three-signal intermodulation and multipath interference , for stronger, cleaner AM and FM reception even in areas with weak signals.

Supertuner IIID

Pioneer's Digital Tuner technology for 2003.

Supertuner IIID features new digital AM/FM tuner circuitry for audibly better FM and AM sound.

Super Nemonic Twist

A passive matrix display type which offers 100ms response times, a 140 degree viewing angle, and high-quality color. Approaches active matrix types at about half the cost.

Super Suspension System

A shock isolation system employing silicon filled shock absorbers, for increased resistance to road vibrations and other shocks.

Super Tweeter

A Driver constructed to reproduce the highest possible frequencies from roughly 13 kHz to 25 kHz. While most standard Tweeters can do an excellent job right up to 16 or 20 kHz, these units deliver the most extreme parts of the upper range for those fortunate (or not) few who can actually hear them.

Surface Mounting

A method of mounting speakers in which the external parts of the upper speaker protrude above the surface on which it is mounted.

Switch

A switch is any form of mechanical, electronic, electromechanical, magnetic, or mercury device that either opens or closes a circuit.

Symmetrical Field Geometry

A speaker motor assembly design that maintains equal magnetic force throughout the travel of the voice coil. This improves bass response and substantially reduces distortion.

System Reset

Resets the audio system to defaults (as programmed by factory)