Specifications

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AFL (After Fade Listen)
A solo function that sends the post-fade
signal of a channel to the monitor output.
Attenuate
Another way of saying ‘reduce in level’.
Auxiliary output
An output consisting of a mix of signals
(from channels and sub-groups) derived
independently of the main stereo and
sub-group mixes. Auxiliary sends can be
used for foldback and for effects sends.
Balance
On a stereo channel, the balance control
is used to vary the relative levels of the
left and right signals into the stereo
mix bus.
Balanced
A method of audio connection which
balances the sound signal between two
wires and a screen which carries no
signal. Any interference is picked up
equally by the two wires, but the signal
on one wire is out of phase with the
other, which means that when they are
recombined the interference is rejected.
Condenser Mic
A microphone that uses a capacitor to
convert air movements into electrical
signals. They require power, which can be
supplied by the Phantom Power found on
Folio desks.
DAT (Digital Audio Tape)
A cassette-based digital recording format.
dB (decibel)
A ratio of two voltages or signal levels. A
change in level of 3dB corresponds to a
perceived doubling of volume to the
human ear. 0dB means no level change.
DI box
A device that enables an instrument with
a low-level output, such as a guitar or
bass, to be connected directly to the line
level input of a mixer.
Dynamic Range
The ability of equipment (such as a Spirit
console) to reproduce very quiet and
very loud sounds – the greater the range,
the better.
Equaliser
A device that allows selected bands within
the audio spectrum to be boosted or cut.
FX Unit
Slang term for effects unit, either a
dedicated processor such as a digital
reverb or delay, or a multi-effects
processor which can produce many
different effects. Effects are usually
connected so that the processed sound
can be mixed back in with the
unprocessed sound in the mixer.
See also ‘outboard’.
Foldback
On stage or in the studio, a feed sent
back to an artist via loudspeakers,
headphones or in-ear monitors, to
enable them to hear the sound they are
producing. A foldback mix is usually
similar to the main mix, but with more
vocals or a particular instrument
as appropriate.
Front Of House (FOH)
In live sound, FOH refers to the sound
and parts of the sound system provided
for the audience – the main system, in
other words. See ‘Monitoring’.
Gain
Amplitude above a given level. Negative
gain means a signal reduction.
Gate
Short for noise gate. An electronic device
that mutes the signal path when the input
signal drops below a threshold level. They
are used to maintain silence in pauses in
the signal, such as in between vocal
phrases or drum hits, when noise might
otherwise become noticeable.
Graphic equaliser.
An equaliser with small faders (or
programmable ‘virtual’ faders in software)
that cut or boost the level of narrow
bands of the audio spectrum. Mainly used
to compensate for imperfect room
acoustics, especially live.
High Pass Filter (HPF)
An electronic circuit designed to filter out
frequencies below the filter’s cut-off
point. If this is set just above deep bass
frequencies, it removes only these from a
signal, and is useful for stopping low-
frequency rumble from on-stage mics
from muddying a mix.
Impedance
For good audio performance, the
impedance of audio outputs should be
low, and input impedances should be
very high.
Line level
A nominal standard signal level used when
connecting one piece of audio equipment
to another. There are two line levels in
use: +4dBu, the ‘professional’ level, and
-10dBV, which is more commonly used in
semi-professional and consumer audio
equipment.
Monitoring
The act of listening to an audio signal over
loudspeakers or via headphones. In live
sound, monitoring also refers to any
separate mix for speakers placed on-stage
so that the musicians can hear themselves
properly (see FOH).
Monitor loudspeakers
Or monitors. Accurate loudspeakers used
to make critical judgements about a mix.
Multicore
A cable with multiple cores, allowing
several signals to be carried independently
but within the same physical casing. Used
extensively in live sound to carry signals to
and from the stage, and in studios for
linking multitrack recorders to mixing
consoles.
Near-field monitor
A compact monitor speaker designed to
be used at a distance of three or four
feet. By listening in the near field (hence
the name), any effects of poor room
acoustics are minimised.
Outboard processors
Strictly speaking, any effect or other
processor – but the term more usually
refers to processors such as compressors,
equalisers or exciters, through which a
channel or mix bus signal passes.
Compressors and equalisers are usually
connected to a mixer via insert points,
which break the internal signal path so
that it can be routed out and back via
the outboard.
Pan
Short for panorama. Controls the levels
sent to the right and left outputs or bus.
Phantom power
This is a way of adding voltage to a
condensor microphone or active DI box,
to power the internal amplifier circuits
without the need for batteries.
Phase
A term used to describe the relationship
of two signals. In phase signals reinforce
each other, out of phase signals produce
cancellation.
Unbalanced
A method of audio connection which uses
a single wire and the cable screen as the
signal return. This method does not
provide the noise immunity of a balanced
connection (see Balanced above).
Unity Gain
A level where a signal is neither boosted
nor cut.
GLOSSARY