Operation Manual
31
insert a break point in the signal path to allow the connection of external
devices, for instance signal processors or other mixers at line level
signals. Nominal levels can be anywhere between -10dBu to +6dBu,
usually coming from a low impedance source.
pan (pot) abbreviation of ‘panorama’: controls levels sent to left and right
outputs.
peaking the point at which a signal rises to its maximum instantaneous
level, before falling back down again. It can also describe an
equaliser response curve affecting only a band of frequencies, (like
on a graphic equaliser), “peaking” at the centre of that band.
peak LED a visual indication of the signal peaking just before the onset of
clipping.
PFL a function that allows the operator to monitor the pre-fade signal
(pre-fade listen) in a channel independently of the main mix.
phase a term used to describe the relationship of two audio signals.
In-phase signals reinforce each other, out-of-phase signals result in
cancellation.
polarity a term used to describe the orientation of the positive and negative
poles of an audio connection. Normally connections are made with
positive to positive, negative to negative. If this is reversed, the
result will be out-of-phase signals (see ‘phase’ above).
post-fade the point in the signal path after the monitor or master fader and
therefore affected by fader position.
pre-fade the point in the signal path before the monitor or master fader
position and therefore unaffected by the fader position.
rolloff a fall in gain at the extremes of the frequency response.
shelving an equaliser response affecting all frequencies above or below the
break frequency i.e. a highpass or lowpass derived response.
spill acoustic interference from other sources.
transient a momentary rise in the signal level.
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 input (see above).
+48V the phantom power supply, available at the channel mic inputs, for
condenser microphones and active DI boxes.