E-M

The amount of movement a speaker cone is capable of.

EBP

Efficiency Bandwidth Product - A guide that helps a designer determine whether a driver is more suitable for a sealed or ported enclosure. EBP of less than 50 indicates the driver should be used in a sealed, 50 - 90 indicates flexible design options, over 90 indicates best for a ported enclosure. EBP = Fs / Qes

Edgewound Ribbon

(Voice Coil) - A practice pioneered by JBL where wire is flattened into a metal ribbon and then wrapped on edge to form a voice coil. This allows for the greatest amount of wire to be located in the gap, increasing performance.

Efficiency

The measure of loudspeaker's ability to convert power to work. Formula: Efficiency = (power out/power in) x 100. Efficiency is always expressed as a percentage.

Efficiency Rating

The loudspeaker parameter that gives the level of sound output when measured at a prescribed distance with a standard level of electrical energy fed into the speaker. The loudspeaker parameter that gives the level of sound output when measured at a prescribed distance with a standard level of electrical energy fed into the speaker.

EIA

Electronics Industries Alliance - Virginia based EIA oversees electronics manufacture, repair, service and sales throughout the U.S.

Electrolytic Capacitor

The most common form of capacitor consisting of a conductive film in an electrolyte. These are canister-shaped and come in the widest range of values. Stiffening caps are electrolytics.

Electromagnetic Field

A field of magnetic energy in the woofer's voice coil created by the audio signal passing through the wire.

Electromagnetic Wave

A wave sent through space and matter by oscillating electric and magnetic fields.

Electrostatic Driver

The Electrostatic Driver generates a motive force for its diaphragm by the interaction of electric rather than magnetic fields as is the case for the dynamic driver. The electrostatic driver is basically "hung" on a frame. It does NOT have a box enclosure, so a great deal of "coloration" (frequency response fluctuations caused by the enclosure reflections) is avoided. A large diaphragm of lightweight material is placed between two perforated (acoustically transparent) electrodes. The diaphragm is electrically polarized at a few thousand volts relative to the electrodes, which maintain a large electrostatic field. The audio signal is applied to the two electrodes in a push-pull fashion. Under these conditions, the diaphragm will vibrate in step with the audio drive signal and produce sound. Because it is a true push-pull driver (i.e. its diaphragm is driven from both front and rear), it operates in a linear fashion.


In an electrostatic driver, the driving force is uniform over the entire diaphragm surface (note that for the Dynamic Driver, the diaphragm is driven over a small portion of its overall surface) as a result, Electrostatic Drivers do not suffer drastically from "breakup" effect as dynamic drivers. Gross distortion typically results only if the driving amplifier clips into the speaker, or when, in an attempt to play the driver at a higher sound level than its design permits, its step-up transformer may reach a point of saturation. Due to the diaphragm of the electrostatic driver being of low mass (lightweight), its transient response is excellent and reproduction of subtle, low-level musical details is exceptional.

EL Backlight

Electro-Luminescent illumination for the lighted portion of a liquid crystal display. Considered to be a step-up featured display.

Emergency Override

A button or switch, possibly separate or hidden from the commonly used controls of a security system, that is used specifically to override or disarm a security system in the event that the primary means is unavailable or disabled.

EMR Detector

A tool used to find the source of low frequency tape head interference (electromagnetic radiation).

Enclosure

A box housing a speaker to separate the front sound waves from those in the rear.

Enclosure Volume

The total amount of internal airspace of an enclosure. Each woofer has an optimal airspace volume that helps it meet it's bass potential. This resonance cavity specification usually measured in cubic feet, includes the net driver and vent volumes. To find the volume of a cube multiply HxWxD in inches. divide the result be 1725 (the number of inches in a cubic foot) to get the volume in cubic feet.

EQ

(Equalizer) - A class of electronic filter circuits designed to augment or adjust electronic or acoustic systems. Equalizers can be fixed or adjustable, active or passive. Most consumer audio equalizers divide the spectrum into 3 to 12 bands, allowing each section to be either increased or decreased in amplitude without changing the response of the rest.
In the early years of telephony and cinema, the first equalizers were fixed units designed to compensate for losses in the transmission and recording of audio signals. Hence, the term equalizer described electronic circuits that corrected for these losses and attempted to make the output equal to the input. Equalizers permit the modification the frequency response spectrum of the signal passing through them; that is, they modify the amplitude versus frequency characteristics.

EQ File

A Custom File feature that allows a user to assign a equalization curve preset to a particular disc, such that when the disc is loaded, that EQ preset is selected automatically.

ESN

Electronic Serial Number - The unique identification number embedded in a wireless phone by the manufacturer. Each time a call is placed, the ESN is automatically transmitted to the base station so the wireless carrier's mobile switching office can check the call's validity. The ESN cannot be altered in the field. The ESN differs from the mobile identification number, which is the wireless carrier's identifier for a phone in the network. MINs and ESNs can be electronically checked to help prevent fraud.

ESP

Electronic Shock Protection - An electronic circuit that stores the audio data stream from a CD or MD in a memory buffer. If the laser pick-up mistracks, audio still flows from the buffer preventing an interruption.

ESR

Erythrocyte Sedimentation Rate - Capacitors have an ESR expressed in ohms or milli-ohms. This loss comes from terminal lead resistance, termination losses, and dissipation in the dielectric material.

EX-Change

A disc changer feature allowing the user to swap non-playing discs, while another disc continues to play.

Excursion

The amount of movement a speaker cone is capable of.

Excursion Limited

(SPL) - The maximum sound pressure level the system can produce given an input signal equal to the rated excursion limited power handling.

Excursion Limited Power Handling

Based on the maximum amount of power the driver can handle without appreciable distortion. All frequencies 30 Hz and above are considered in this limit.

Extended Pole Piece

A disc changer feature allowing the user to swap non-playing discs, while another disc continues to play.