E - Refer to Exa
Earth - European terminology often given to the electrical ground or chassis ground potential.
EBP - Refer to Efficiency Bandwidth Product
Echo - The distinct repetition of an initial sound, caused by the reflection of the sound waves upon a surface. We recognize a sound as an echo when the distance between the source and the reflection is far enough apart that we can detect the time delay between one and the other. Essentially, reverberation is the combination of many echoes occurring too rapidly to hear each individually. In the studio, echoes can be reproduced acoustically or simulated by a digital signal processor.
Echo Chamber - An enclosed room designed with reflective, non-parallel surfaces for the purpose of creating acoustic echoes (reverberation).
ECM - Refer to Engine Control Module
ECU - Refer to Electronic Control Unit
EDGE - Refer to Enhanced Data Rate for Global Evolution
Edit - To change one or more parameters of a recorded sound after the fact. This can take many forms, including “punching in” a section of the music that is re-recorded to replace the original version; altering the shape/size of waveforms graphically; changing the sequence of playback; and many others. Analog editing would typically involve splicing the magnetic tape on which the audio signals were recorded. These days, almost all editing in the studio is done via computer using a digital audio workstation (DAW).
Effect Loop - An effects loop is a series of audio effects units, connected between two points of a signal path (the route that a signal would travel from the input to the output); usually between the pre-amp and power amp stages of an amplifier circuit, although occasionally between two pre-amp stages.
Efficiency – The measurement of a loudspeaker or amplifier’s ability to convert input power to output power (work). Formula : Efficiency = (power out/ power in) X 100. Efficiency is always expressed as a percentage.
Efficiency Rating - the loudspeaker parameter that shows the level of sound output when measured at a prescribed distance with a standard level of electrical energy fed into the speaker (usually recorded as XdB @ 2.83V input signal from 1 meter of distance. However, a driver with a high efficiency rating needs a larger box to play a lower frequency than a driver with a lower efficiency rating.
Efficiency Bandwidth Product (EBP) - is a number which shows the trade-off between efficiency and bandwidth of a driver. It is useful in determining if a driver is suited for a sealed or vented box and is also used to determine suitability for horn loading.
EL Backlight - Electroluminescence Backlight is a solid state phenomenon which uses colored phosphors, not heat, to generate light. EL backlights are very thin, lightweight and provide an even light. They are available in a variety of colors, with white being the most popular for use with LCDs.
Electret -A dielectric plate that is designed with permanent polarity, allowing it to function similarly to a magnet. (“Electret” comes from the words “electricity” and “magnet.”) Used in some microphone types in place of a capacitor (condenser).
Electrical Current - a path in which electrons from a voltage or current source flow. The point where those electrons enter an electrical circuit is called the "source" of electrons.
Electronic Serial Number (ESN) - The serial number of an electronic device.
Electrolyte - The name for the mixture of diluted sulfuric acid found in standard lead-acid vehicle storage batteries.
Electrolytic Capacitor - A capacitor with a negative and positive terminal that passes only alternating current. Electrolytics are available in polarized and non-polarized configurations. Non-polarized (NP) capacitors are useful as inexpensive crossovers, blocking low frequencies from passing through to mid- or high-frequency speakers. Polarized capacitors have specific positive and negative poles. Polarized capacitors are used for storing and releasing energy.
Electromagnet - A soft metal core made into a magnet by the passage of electric current through a coil surrounding it.
Electromagnetic Field (EMF) - A field of magnetic energy put out because of current traveling through a conductor.
Electromagnetic Interference (EMI) - Also referred to as radio-frequency interference (RFI) when in the radio frequency spectrum, is a disturbance generated by and external source that affects an electrical circuit by electromagnetic induction, electrostatic coupling, or conduction.
Electromagnetic Radiation Detector (EMR Detector) - A tool used to find the source of low-frequency electromagnetic interference known as electromagnetic radiation, or EMR.
Electromotive Force (EMF) - Denoted with “E” and measured in volts. This is the voltage developed by any source of electrical energy such as a battery or dynamo. It is generally defined as the electrical potential for a source in a circuit. A device that converts other forms of energy to electrical energy supplies an EMF to a circuit.
Electron - An electron is a negatively charged component of an atom. Electrons exist outside of and surrounding the atom nucleus. Each electron one unit of negative charge and has a very small mass as compared with that of a neutron or proton.
Electronic Shock Protection (ESP) - An ESP system tries to get lean sound output while external shocks exist. ESP does not clear noises caused by scratched or dirty CD’s. This feature may also be referred to as Electronic Skip Protection.
Electrostatic Loudspeaker (ESL) - An electrostatic loudspeaker is a loudspeaker design in which sound is generated by the force exerted on a membrane suspended in an electrostatic field.
EMF - Refer to Electromagnetic Field or Electromotive Force
EMI - Refer to Electromagnetic Interference
Emergency Override - A button or switch installed in the vehicle is used specially to override or disarm a security system in the event that the primary means is unavailable or disabled.
EMR Detector - Refer to Electromagnetic Radiation Detector
Enclosure - An artificial or natural barrier that seals off an area. In car audio an enclosure is typically a cabinet constructed for a subwoofer or speaker. Subwoofer enclosures are typically made from wood such as, Medium Density Fiber (MDF) board and Birch wood for the most air tight seal, you may also see different types of acrylics used in marine applications. Prefabricated enclosures are made to fit generally any subwoofer of the size offered in an amount of air space that is fairly universal for subs of that size and can come in many different general alignments. A custom subwoofer enclosure is typically constructed to the specifications of the component being used in the application or to fit the area given for the subwoofer placement.
Enhanced Data Rate for Global Evolution (EDGE) - A GSM-development path for delivery of data, delivered at rates up to384 Kps. The standard is based on the GSM technology platform and uses the TDMA approach.
Engine Disable - A means, either electrical or mechanical, of preventing the vehicle’s engine from either starting or running. The most common variety of engine disable uses a simple automotive relay to inhibit either the starter or the ignition.
Entry Delay - The time interval a security system waits before sounding the alarm after a vehicle’s door has been opened.
Environmental Protection Agency (EPA) – The federal agency that regulates motor vehicle emissions compliance standards in the United States. Also refer to CARB.
Envelope - The collective term for the four elements of the lifespan of a sound: Attack, Decay, Sustain and Release (ASDR). The envelope of a sound describes how a sound or audio signal varies in intensity over a period of time.
EPA - Refer to Environmental Protection Agency
Equalization - The act of making equal or uniform. Equalisation, leveling. Human action, human activity, act, deed - something that people do or cause to happen. The process of balancing, reconciliation. Getting two things to correspond
Equalizer - A built-in EQ lets you tailor the sound to your listening tastes and to your vehicle's acoustics. Receivers with built-in EQs will have one or more equalizer "bands" in addition to standard bass and treble controls. These equalizer "bands" usually have fixed center frequencies and bandwidths (although some may be adjustable).
More sophisticated built-in EQs offer parametric equalization, which allows you to set the amount (in dB) by which a certain frequency band is boosted or cut — and determine the width and/or center frequency of this band. This gives you extremely precise control of the tonal balance in your vehicle.
Equalized Presets - Preset EQ curves are stored tone settings — boosting and cutting different frequencies can make big changes in the way your music sounds. Preset EQ curves are stored in memory, and are easily activated. If you listen to a wide variety of music, these presets are useful for making dramatic tonal changes instantly. (For example, you could use one EQ preset with heavy bass boost for rap or reggae, and a second preset with flat bass and a slight midrange/treble boost for jazz. This saves you from constant readjustment of the tone controls.)
Equal Loudness Contours - A drawing of several curves showing how loud the tones of different frequencies would have to be played for a person to say they were of equal loudness. Refer to Fletcher-Muson Curves
ESN - Refer to Electronic Serial Number
ESL - Refer to Electrostatic Loudspeaker
European Tuning - The European tuning interval of .05 MHz is different from the US tuning interval of .2 MHz. If a CD receiver also has European tuning, it is compatible with the European scale and can be used in many European countries.
EV-DO - Refer to Evolution-Data Optimized
Evolution-Data Optimized (EV-DO) - Also known as Evolution-Data Only. EV-DO is a wireless air interface standard based on CDMA technologies and is part of the CDMA 2000 family. The primary use for an EV-DO capable network is delivering wireless internet access to mobile users.
Evolved High Speed Packet Access (HPSA+) – A CDMA based air interface in late 3G/ early 4G applications. HPSA+ also uses MIMO multi-antenna transmission technology.
Exa (E) - A prefix meaning 1018 or 1,000,000,000,000,000,000
Exit Delay - The name given to the amount of time a security system waits once it’s given a command to arm. Exit delays are usually found on non-remote security systems that rely on keypads or the ignition switch to arm. This delay gives the operator time to exit the vehicle before the system arms.
Expertise - Expert skill or knowledge in a particular field.
External Regulator - Also referred to as a voltage regulator, it is designed to automatically or sometimes manually maintain a constant voltage level. A voltage regulator may be a simple feed-forward design or may include negative feedback. It may use an electromechanical mechanism, or electronic components. An external regulator is typically used in car audio to regulate the voltage of the engine alternator.