Glossary of Audio, Recording and Music Terms "E"

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E

Early Reflections –The first echoes in a room, caused by the sound from the sound source reflecting off one surface before reaching the listener.

Echo – 1) One distinct repeat of a sound because of the sound reflecting off a surface. 2) Loosely, used to mean reverberation (the continuing of a sound after the source stops emitting it, caused by many discrete echoes closely spaced in time). 

Echo Chamber – 1) A room designed with very hard, non-parallel surfaces and equipped with a speaker and microphone. 2) Any artificial or electronic device that simulates the reverberation created in a room. 

Echo Return –An input of the console, which brings back the echo (reverberation) signal from the echo chamber or other echo effects device. 

Echo Send –The output of a console used to send a signal to an echo chamber or delay effects device. 

Echo Send Control –A control to send the signal from the input module to the echo chamber or effects device via the echo buss.

Editing – 1) Changing the sequence of a recording by cutting the recording tape and putting the pieces together in the new sequence with splicing tape. 2) Punching in and then punching out on one or more tracks of a multitrack tape recorder to replace previously recorded performances. 3) Changing the sequence of a digital recording's playback by computer program.

Effects – 1) Various ways an audio signal can be modified by adding something to the signal to change the sound. 2) Short for the term Sound Effects (sounds other than dialogue, narration or music like door closings, wind, etc. added to film or video shots). 

Effects Track – 1) In film production audio, a recording of the mixdown of all the sound effects for the film ready to be mixed with the dialogue and music. 2) In music recording, one track with a recording of effects to be added to another track of a multitrack recording. 

Electret - A type of microphone design, similar to the condenser. Instead of using a polarizing plate, which requires an external power supply to operate, there is a permanently charged plate made with an electret, an acronym for "electricity" and "magnet

Electret Condenser –  A condenser microphone that has a permanently polarized (charged) variable capacitor as its sound pressure level sensor. 

Electric Current – A more formal term meaning the same as the term Current (the amount of electron charge passing a point in a conductor per unit of time).

Electricity –  Electrical current or the amount of electron charge passing a point in a conductor per unit of time or voltage - the force pushing electrons to obtain electrical current.

Electromagnetic Field – Magnetic energy put out because of current traveling through a conductor.

Electromagnetic Induction or Pick Up – The generation of electrical signal in a conductor moving in a magnetic field or being close to a changing magnetic field.

Electromagnetic Theory – A statement of the principles behind electromagnetic induction: When a conductor cuts magnetic lines of force, current is induced in that conductor. 

Electrons – Negatively charged particles, which revolve around the center of atoms. The movement of such electrons down a conductor is what causes electrical current.

Electrostatic Charge – The excess or deficiency of electrons in any given area.

Electro-Magnetic Interference (EMI) - A type of audible interference caused by large power current flowing through cables in close proximity to audio equipment or cables. The magnetic field around the power cables permeates the audio cables, resulting in undesirable hums or buzzes. Switching dimmers, fluorescent light ballasts, neon lights, flicker lights, computers, and RF transmitters are all generators of EMI. Careful routing of audio cables and adherence to EMC standards can alleviate the problem. [Audio cables are not the only cables susceptible to EMI; data cables, often a source of EMI, can also be adversely affected by EMI.]

Engineer – A technician in charge of a recording session, often called a Recording Engineer, is  a person with an engineering degree and/or with sufficient experience in the field to be equivalent to the education one would receive earning an engineering degree.

Envelope – How a sound or audio signal varies in intensity over a time span. It can also refer to how a control voltage varies in level over time controlling a parameter of something other than gain or audio level.

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.

Equalization – When the amplitude of audio signals at specific set of frequencies are increased or decreased more than the signals at other audio frequencies.

Equipment Rack - A cabinet with rails (or free standing rails) that have holes to accept screws at standard spaces and used to house outboard gear.

Error Concealment – Putting replacement information bits into a digital audio signal to replace lost bits when the digital recording or processing system cannot verify whether the lost bits were l's or 0's.

Error Correct – Exact replacement of lost information bits in digital audio.

Error Detection –The process of discovery that sonic information bits have been lost in digital audio.

Expander –- A device that causes expansion of the audio signal. 

Expansion – The opposite of compression; for example, an expander may allow the signal to increase 2 dB every time the signal input increased by 1 dB.

Expansion Ratio – How many dB the output signal will drop for every 1dB fall in the input signal below the threshold.