Audio Terminology And Definitions Dictionary

 

Early Reflection   These are the first sounds that reach the listener's ears after the direct sounds from the loudspeaker. Typically, early reflections come from the walls closest to the front speakers.

 

Earth   Sometimes called ground, earth is the zero reference point for electrical circuits including the mains electricity supply. 

 

Earth Loop  A source of hum audible through the loudspeakers, at mains frequency (or multiple thereof), and caused by failure to find a common single earth. Incorrect earthing of tonearms and turntables is perhaps the most common source of earth loops.

 

Echoic  Literally prone to echo. Hard surfaces in listening rooms will result in a lot of high frequency reflections and a generally echoic sounding acoustic. The technical term for this is a long reverberation time. It is to be avoided if possible. 

 

EDTV     EDTV stands for Enhanced Definition Television, or those sets with a native resolution of 852 x 480 pixels. Although this resolution is higher than the standard TV, it is not HDTV. True HDTV resolution requires a display with resolution of 1280 x 720 pixels or higher.

 

Effects     Literally speaking, any special effect other than dialog and music that occurs in a film's soundtrack.

 

Efficiency  A measure of the percentage of electrical input that a loudspeaker converts into acoustic output. Most conventional home audio speakers are roughly 1 to 3 percent efficient. (See also: sensitivity.)

 

EIA   Electronic Industries Association. The United States national organization of electronic manufacturers. It is responsible for the development and maintenance of industry standards for the interference between data processing machines and data communication equipment.

 

Eigentone   A standing wave set up between two parallel room surfaces. The frequency of a standing wave is determined by the distance apart of the parallel surfaces. A listening room where the long axis is double that of the short axis is likely to have acoustics problems since the first standing wave will be augmented by one at twice the frequency. This second harmonic will be difficult for the ear to differentiate and the effect will be a pronounced and audibly intrusive bass resonance easily excited by music signals.

 

Electromagnetic Induction  The process whereby an 
electrical current is induced in one of two ways. Either 
a magnet moves within a structure of coiled wires, or 
vice versa. It is the foundation stone or underlying
principle of all moving coil loudspeaker drive units, 
moving coil cartridges and moving magnet cartridges.

 

Electrostatic  The electrical force induced when friction is applied between two nonconductive materials (eg plastic and paper). The principle has been applied to loudspeaker design. The Electrostatic loudspeaker works by applying a fixed or polarizing voltage to an electrostatically charged flat diaphragm mounted between two transformer coupled plates fed anti-phase signal. 

 

EMI   Electromagnetic Interference. External signals that disrupt the data being transmitted on the local area network or electronic device being operated.

 

Encoding/Decoding     Converting information from one form into another, and then back into its original form. All digital audio technologies use some form of encoding to store and transmit audio information as number codes, and decoding to convert the number codes back into audio information.

 

Envelopment The characteristic of a listening space that implies the listener is surrounded ("enveloped") by sound. Proper surround-channel envelopment of the audience is considered a very important characteristic of high-quality home and commercial theaters.

 

Equalization   A correction made on playback of tape recordings to restore correct linear frequency balance 

 

Ethernet Connection   Ethernet or LAN (local area network) connections are increasingly common in home entertainment components. They allow direct access to the Internet, usually through a router. Common uses include streaming media, firmware updates, etc.

 

Excursion    A measurement of how far a driver diaphragm can move. Look for "peak to peak" measurements. Some dynamic woofer diaphragms move more than a ½" when they're really pumping out the bass.

 

Equalization (EQ)   Deliberate electronic alteration of frequency response with the goal of attaining a specific final result, either better sound or an altered response better suited for a special effect. Powered subwoofers often use EQ to augment their natural bass output.