A - Refer to Attenuation
A2DP - Refer to Advanced Audio Distribution Profile
AAC - Refer to Advanced Audio Compression
Abrasives - Substances used to wear away a surface by friction. Common abrasives in mobile electronics fabrication include sandpaper, 3M Roloc discs, foam sanding pads and even lighter duty scrub pads to slightly remove surface finish top coats.
Absorbed Glass Mat (AGM) - As opposed to Lead Acid batteries, AGM batteries utilize woven strands of fiberglass to hold the electrolytes to the plates for the lifetime of the battery. These batteries good to use when leaving a vehicle or boat without being started for long periods of time.
Accessories - Comfort, convenience and safety products not essential to the performance of a vehicle, such as audio, security products, floor mats and seat covers. In the business of automotive, anything not supplied with the basic vehicle in all instances for a given trim level or package is an accessory. Those accessories can be available from the vehicle manufacturer (OEM), from the vehicle dealer or from the aftermarket suppliers and retailers.
Accessory Power - Also called Accessory Power, refers to the position of the key in the ignition switched; wire showing 12 volts (+) when in the ignition switched position. Some newer vehicles do not offer a dedicated ignition switch. Also shows +12 volts in ACC and RUN positions, but no power in START position. Controlled by a positive switching non MUX ignition switch.
Acoustic Absorption - Measured in sabine units, Acoustic Absorption is the sound deadening property of any given dampening substance.
Acoustical Energy - Energy consisting of fluctuating waves of pressure referred to as sound waves.
Acoustic Feedback - A high pitched “squealing” sound when the output of an audio circuit is fed back in phase into the circuit’s input.
Acoustics - A science in dealing with the production, effects, and transition of sound waves through various mediums.
Acoustic Suspension - The inner air pressure of a closed or sealed subwoofer enclosure provides a sort of suspension that allows the diaphragm or cone to easily return to its resting position. This affect caused by the given characteristics under the optimal circumstances, can allow for greater power handling of the driver and is often referred to as acoustic suspension.
Active Arming - A method of arming a security system that requires some action, such as pressing a button on a remote transmitter or entering a code on a keypad.
Active Display - A step-up display feature that generates animated patterns for both segment and dot matrix LCDs that proceed the sequential display of information such as clock, Custom File titles and radio station frequencies.
Actuator - A type of motor for moving or controlling a mechanism or system. It is operated by a source of energy, usually in the form of an electric current, hydraulic fluid pressure or pneumatic pressure, and converts that energy into some kind of motion.
ADSR - An acronym that stands for Attack, Decay, Sustain, Release and is a means to replicate those respective elements of a sound. It is especially used in sound designing with electronic music instruments.
Advanced Audio Compression (AAC) - An encoding and variable compression scheme for digital music. AAC is the default compression scheme for iTunes when “ripping” music to the program or purchased music from the iTunes service. Also referred to as Advanced Audio Coding.
Advanced Audio Distribution Profile (A2DP) - Advanced Audio Distribution Profile – A Bluetooth profile for streaming 2 channels of 20Hz-20kHz audio from one Bluetooth device to another.
Advanced Television Systems Committee (ATSC) - A committee for digital television. The ATSC standards describe the way digital “over the air” television is broadcast to compatible digital television (DTV) receivers.
Advanced Television Systems Committee M/H (ATSC M/H) – ATSC digital television signals intended for mobile or handheld devices. To receive an ATSC M/H signals, the device must have an ATSC M/H tuner and the broadcaster must send ATSC M/H signals, which are often in addition ot their normal ATSC broadcast. The availability of ATSC M/H signals varies by city and region on broadcast support.
Aesthetics - A branch of philosophy dealing with the nature of art, beauty, and taste, with the creation and appreciation of beauty. It’s more scientifically defined as the study of sensory or sensori-emotional values, sometimes called judgments of sentiment and taste. More broadly, scholars in the field define aesthetics as "critical reflection on art, culture and nature.
AGM - Refer to Absorbed Glass Mat
Ah - Refer to Ampere Hour
Air Gap - The space between the top plate and the pole piece. This is where the voice coil sits.
Air Horns - A type of horn that uses compressed air instead of an electric diaphragm or voice coil to produce sound. These horns are usually driven by an electric air pump that receives its trigger from a host security system.
Air Interface - The operating system of a wireless network. Underlying technologies include AMPS, TDMA, CDMA, GSM, and iDEN with a host of derivatives built on the basis of those technologies. The air interface type(s) are often one or the other based on service provider.
Alarm Reset - The property of an alarm system that resets the alarm to an alarmed state after a preset period of time.
Aliasing Noise - The result of the sampling frequency not being at least double the highest analog frequency during the digital encoding of an analog signal.
Alignment - A class of enclosure parameters that provides optimum performance for a woofer with a given value of Q. In audio this typically refers to the different types and designs of subwoofer enclosures.
Alpha - Term used in sealed enclosure designs to mean the ratio of Vas to Vb, where Vb is the volume of the box you will build.
Alternating Current (AC) - The movement of a current that periodically switches polarity. As opposed to a direct current (DC), this flows in one direction.
Alternator - An electromechanical device that converts mechanical energy into electrical energy in the form of alternating current. Usually driven be by automotive internal combustion engine, and uses a magnetic field to produce the alternating current.
Alternator Whine - A siren like whining that occurs when engine RPM’s increase. The noise is often the result of a voltage differential created by more than one ground path between the audio system components or fatigued charging system components such as the alternator or battery.
Aluminum (Al) - Is a silvery white metal and the most abundant naturally occurring metal found beneath the Earths crust. Aluminum is nonmagnetic and does not easily ignite. The properties of aluminum that provide the most advantage to the audio world are it’s light weight, durable, electrical conduction, thermal conduction, and ability to resist corrosion. Aluminum has 59% electrical and thermal conductivity of Copper, which the two metals may be compounded to create a cheaper and less efficient conductor. Because it has one-third the density and stiffness of Iron and Steel, aluminum is used in making driver baskets, screws and bolts. It may also be found in use as outer casing to external filters, some amplifiers, terminals, and butt-connectors.
Ambience Synthesizer - A unit that produces an artificial ambience pattern; one that is used to create the impression of the listener and/or performer being in a particular performance space. Also known as an “effects processor.”
American Wiring Gauge (AWG) - Is a standardized wiring system also referred to as Brown & Sharpe wiring gauge, used since 1857 predominantly in the U.S. and Canada for the diameters of round, solid, nonferrous, electrically conducting wire. The cross section of the wire is important for determining its current-carrying capacity.
Ammeter - An instrument used for measuring the amount of current flowing in a circuit.
Amperage - A unit of electrical current; the force through which the energy is pushed through a conductor. Measured in Amperes, or Amps for short. Ohm’s Law symbol for Amperes is “I.”
Ampere (A) - Often referred to as Amps, is a unit of current named after French Mathematician and Physicist Andre-Marie Ampere whom is considered the father of electrodynamics. The measures of a constant current will be defined in amperes and the flow of charge through a circuit over a period of time will be defined in coulombs. In this way, amperes can be view as a flow rate, i.e. number of particles (charge) transiting per unit time, and coulombs simply as the number of particles.
Ampere Hour (Ah) - Also referred to as Amp Hour, this is a unit of electric charge, having dimensions of electric current multiplied by time, equal to the charge transferred by a steady current of one ampere flowing for one hour, or 3,600 coulombs. The commonly seen milliampere hour is one-thousandth of an ampere hour.
Amp Hour - Refer to Ampere Hour
Amplification - An increase in signal level, amplitude, or magnitude.
Amplifier - Is a device for increasing the power of a signal by use of an external signal source. The input and output current of an amplifier is typically measureable in voltage.
Amplitude - The maximum value of a periodically varying quantity. The measure of how much signal is contained in an alternating signal. Amplitude is typically expressed in units of Volts or decibels (dB).
Amplitude Modulation (AM) - Also known as AM Stereo, the encoding of a carrier wave by variation of it's amplitude in accordance with an input signal.
Analog - A way to represent data by means of continuously variable quantities. A control or circuit which continuously changes the level of a signal in direct relationship to the control setting. An electrical signal whose frequency and level vary continuously in direct relationship to the original acoustical sound waves (something that is analogous).
Analog Switch - A hardwire-oriented switch that only passes signals that are faithful analogs of transducer parameters.
Analog to Digital Convertor (ADC) - A circuit that converts an analog signal into a digital signal. With a continuous input signal the ADC will check the signal several time per second (sampling), assign values to the samples and represent it as a binary number (quantization and encoding).
Analogous - Alike in certain ways. Similar in function but not in origin or structure.
Anode - The electrically positive pole of an electronic device such as a semiconductor. A diode, for instance, has a positive and a negative pole; these are known as the anode and the cathode.
Antenna - An apparatus used for sending and receiving radio waves, usually constructed of metal. The best performance from an satellite, analog, or digital antenna will be when installed in line of sight with the sky.
Antenna Trimmer - An adjustment found on analog radios used to maximize AM reception. Turning this trimmer to the point where the sound is the loudest increases the sets signal to noise ratio optimizing performance.
Anti-theft Protection - Some stereos give you the option of setting up a security code. This is usually in addition to having a detachable faceplate. The security code is a three or four button combination, usually using the radio preset buttons, that has to be entered before the stereo will function. These anti-theft stereo security codes can be found on some manufacturer source units as well. A detachable faceplate lets you remove the control panel of your receiver easily, and take it with you when you leave the car. The stereo is useless to thieves without the faceplate, so the temptation to break in your car is greatly reduced. All but a handful of the receivers we offer come with a detachable face.
Aperiodic - Refers to a type of bass-cabinet loading. An aperiodic enclosure type usually features a very restrictive, (damped), port. The purpose of this restrictive port is not to extend bass response, but lower the Q of the system and reduce the impedance peak at resonance. Most restrictive ports are heavily stuffed with fiberglass, dacron or foam.
Arm - The term used to describe the act of causing a security system to reach a state in which it will protect the vehicle.
Armature - Generally refers to one of the two principal electrical components of an electromechanical machine–generally in a motor or generator, but it may also mean the pole piece of a permanent magnet or electromagnet, or the moving iron part of a solenoid or relay. The other component is the field winding or field magnet. The role of the "field" component is simply to create a magnetic field (magnetic flux) for the armature to interact with, so this component can comprise either permanent magnets, or electromagnets formed by a conducting coil.
Arming Delay - A term used to describe the elapsed time between the moment a security system is first told to arm and the moment it is actually armed. This normally applies only to systems that are passively armed, but it can apply to actively armed systems, as well.
Atom - A unit of matter, the smallest unit of an element, having all the characteristics of that element and consisting of a dense, central, positively charged nucleus surrounded by a system of electrons. The entire structure has an approximate diameter of 10*8 centimeter and characteristically remains undivided in chemical reactions except for limited removal, transfer, or exchange of certain electrons. Atoms with 1-3 electrons on the outer “shell” are considered conductors when the electrons break free.
Atomic Nucleus - Refer to “Nucleus”
Attenuate - To lessen the amount of force, magnitude, or value of something.
Attenuator - A device to decrease or increase the strength of a signal.
Audio Frequency (AF) - Also known as audible frequency, is characterized as a periodic vibration whose frequency is audible to the average human. It is the property of sound that most determines pitch and is measured in hertz (Hz).
Audio Frequency Spectrum - The band of frequencies extending roughly from 20 Hz to 20 kHz.
Audio Oscillator - A device that produces tones at specific frequencies for testing either equipment or entire systems.
Auto Electric - Automotive repair business specializing in electrical and lighting products for commercial and passenger vehicles, as well as in the repair/ replacement of failing electrical parts. Many retailers selling and installing car audio and security products can also perform these Auto Electric services because of their ability to troubleshoot vehicle electrical systems.
Audio Spectrum - The audible frequency range at which humans can hear. The audio spectrum spans from 20 Hz to 20 kHz and can be effectively broken down into 7 different frequency bands, with each having a different impact on the total sound. The break down of these 7 frequency bands is as follows; Sub-bass 20-60 Hz, Bass 60-250 Hz, Low Midrange 250-500 Hz, Midrange 500-2 kHz, Upper Midrange 2-4 kHz, Presence 4-6 kHz and Brilliance 6-20 kHz.
Audio/Video (AV) - AV is the abbreviation for audio/video and is frequently used as a generic term for the audio and video components and capabilities in vehicle, and home entertainment systems and related product descriptions and reviews.
Audio Video Remote Control Profile (AVRCP) - This profile allows for Bluetooth control and compatibility beyond that of the HP and HFP profiles. It allows the user control to play/pause and skip track without having to use the portable device or phone and may also display artist, title and album on the aftermarket stereo. Bluetooth media streaming and control via aftermarket stereo.
Auto Eject - Feature of a cassette player that ejects the tape when it has finished playing one side.
Auto Loud - Automatically provides low frequency boost for listening at low levels.
Auto Memory - Is a tuner feature that automatically finds the strongest stations in the local area, and places them in preset memories.
Automotive Aftermarket - Replacement or add-on purchases for a vehicle after its original sale, including parts, accessories, lubricants, fuel, appearance products and repairs. The Mobile Electronics Aftermarket (also referred to as “Car Audio”) is but one segment of the larger overall Automotive Aftermarket industry.
Auto Replay - Feature of a cassette player that automatically rewinds a tape when it has reached the end of one side, then begins to replay.
Auto Reverse - Feature of a cassette player that automatically plays the reverse side of a tape when one side has reached the end.
Auto Reset - The ability of a security system to automatically reset itself after being triggered.
Auto Stop - Feature of a cassette player that automatically shuts off power when a tape has reached the end of either side in any mode.
Automatic Gain Control (AGC) - A circuit that continuously adjust the recording amplifier gain to maintain a relatively constant recording level.
AUX - Refer to Auxiliary Input
Auxiliary Input (AUX) - An input on the face or rear of the receiver that enables you to connect a plug-and-play satellite radio tuner or portable music player (CD, MP3, or cassette) to the receiver. The input jack can be either Mini or RCA.
AV - Refer to Audio/Video