Mackie SR24•4 Owner's Manual page 46

echo
face such as a wall or a floor. Reverberation and
echo are terms which can be used interchange-
ably, but in audio parlance a distinction is
usually made: echo is considered to be a dis-
tinct, recognizable repetition (or series of
repetitions) of a word, note, phrase or sound,
whereas reverberation is a diffuse, continuously
smooth decay of sound. Echo and reverberation
can be added in sound mixing by sending the
original sound to an electronic (or electronic/
acoustic) system which mimics natural echoes,
and then some. The added echo is returned to
the blend through additional mixer inputs.
Highly echoic rooms are called live; rooms with
very little echo are called dead. A sound source
without added echo is dry; one with reverb or
echo added is wet.
effects devices
verb, delay, spatial or psychoacoustic effects
to an audio signal. An effects processor may
be used as an insert processor on a particular
input or subgroup, or it may be used via the
aux send/return system. See also echo, reverb.
Appendices
EQ
EQ curve
frequency on the x (horizontal) axis and ampli-
tude (level) on the y (vertical) axis. Equalizer
types and effects are often named after the
shape of the graphed response curve, such as
peak, dip, shelf, notch, knee and so on.
equalization
changing the frequency response of a circuit,
sometimes to correct for previous unequal re-
sponse (hence the term, equalization), and
more often to add or subtract level at certain
frequencies for sound enhancement, to re-
move extraneous sounds, or to create
completely new and different sounds.
EQ; so are the units called parametrics and
graphics and notch filters.
to do with what a graph of the frequency re-
sponse would look like. A flat response (no EQ)
is a straight line; a peak looks like a hill, a dip
is a valley, a notch is a really skinny valley, and
a shelf looks like a plateau (or a shelf). The
slope is the grade of the hill on the graph.
44
Echo is the reflection of sound from a sur-
External signal processors used to add re-
See equalization
A graph of the response of an equalizer, with
Equalization (EQ) refers to purposefully
Bass and treble controls on your stereo are
[A lot of] how we refer to equalization has
Graphic equalizers have enough frequency
slider controls to form a graph of the EQ right
on the front panel. Parametric EQs let you
vary several EQ parameters at once. And a fil-
ter is simply a form of equalizer which allows
certain frequencies through unmolested and
other frequencies reduced or not at all.
Aside from the volume control, EQs are prob-
ably the second most powerful controls on any
mixer (no, the power switch doesn't count!).
fader
Another name for an audio level control.
Today, the term refers to a straight-line slide
fader rather than a rotary control.
family of curves
A composite graph, showing on one chart
several examples of possible EQ curves for a
given equalizer or equalizer section.
filter
A simple equalizer designed to remove cer-
tain ranges of frequencies. A low cut filter
(also called a high pass filter) reduces or
eliminates frequencies below its cutoff fre-
quency. There are also high cut (low pass)
filters, bandpass filters, which cut both high
and low frequencies but leave a band of fre-
quencies in the middle untouched, and notch
filters, which remove a narrow band but leave
the high and low frequencies alone.
flanging
A term for phasing. Before digital delay ef-
fects units, phasing could be accomplished by
playing two tape machines in synchronization,
then delaying one slightly by rubbing a finger
on the reel flange. Get it?
FOH
An acronym for Front Of House. See house
and main house speakers.
frequency
Frequency is the number of times an event
repeats itself in a given period. Sound waves
and the electrical signals which represent
sound waves in an audio circuit have repeti-
tive patterns which range from a frequency of
about 20 repetitions per second to about
20,000 repetitions per second. Sound is the vi-
bration or combination of vibrations in this
range of 20 to 20,000 repetitions per second
which gives us the sensation of pitch, harmon-
ics, tone and overtones. Frequency is
measured in units called Hertz (Hz). One
Hertz is one repetition or cycle per second.
fully balanced
See balanced.