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.

Earth

The British version of the term Ground (In electronics, a place that has zero volts).

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.

Edit

A switch that does different things depending on the operational mode that the machine is in:

1. If a computer-controlled transport is in “Stop,” pushing the “Edit” switch deactivates the computer-controlled tension system and allows the reels to be moved by hand to find the exact spot desired on the tape.
2. If the machine is in “Play”, the “Edit” switch makes the take-up reel cease taking up the tape and it falls to the floor.
3. If the machine is in a fast-wind mode, the tape lifters are defeated so the tape is in contact with the reproduce head and the engineer can hear where the selections begin and end.

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. Electronic boxes (usually rack mounted) added to a PA system to subtly change and enhance the signals going through it. Examples include; Reverb, Delay, Compressor, Chorus.
2. Various ways an audio signal can be modified by adding something to the signal to change the sound.
3. Short for the term Sound Effects (sounds other than dialogue, narration or music like door closings, wind, etc. added to film or video shots).

Efficiency

The acoustic power delivered for a given electrical input. Often expressed as decibels/watt/meter (dB/w/m).

Electret Mic

A condenser microphone where the capacitor plates are given a charge during manufacture which they retain, therefore requiring no external power supply.

Electret Condenser

A condenser microphone that has a permanently polarised (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).

Electric Instrument

Any musical instrument that puts out an electrical signal rather than an acoustic sound.

Electricity

Electrical current (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 travelling 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.

Electronics

1. On a tape machine, the housing for and the channel circuitry which processes the signal to be fed to the heads, provide bias, and playback.
2. The branch of science dealing with the behaviour of electrons/charges in vacuums, gases, semiconductors and special conductors.

Electrons

Negatively charged particles, which revolve around the centre of atoms. The movement of such electrons down a conductor causes electrical current.

Electrostatic Charge

The excess or deficiency of electrons in a given area.

Engineer

1. A technician in charge of a recording session; Also called Recording Engineer.
2. A person with an engineering degree.
3. A person with sufficient experience in the field to be equivalent to the education one would receive earning an engineering degree.

Envelope

1. How a sound or audio signal varies in intensity over a time span.
2. How a control voltage varies in level over time controlling a parameter of something other than gain or audio level.

Equaliser (Parametric, Graphic)

This is used to filter out and adjust specific frequencies in the PA. This is the part of the PA where you have the most control over the band’s overall sound. It is also the number one weapon against feedback.

Equalisation

1. The process of adjusting the tonal quality of a sound. A graphic equaliser provides adjustment for a wide range of frequency bands, and is normally inserted in the signal path after the mixing desk, before the amplifier. See Feedback.
2. Any time the amplitude of audio signals at specific set of frequencies are increased or decreased more than the signals at other audio frequencies.

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.

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 but can make a good guess by comparing the known bits that were close in position to the lost bits.

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.

Error Message

A prompt on a computer screen telling the operator that an error has occurred.

ESL

Abbreviation for electrostatic loudspeaker.

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 is increased by 1 dB.