STEREO INPUT CHANNELS 13-20
STEREO INPUT L & R
These inputs accept 3-pole ‘A’ gauge (TRS) jacks. Use these inputs
for sources such as keyboards, drum machines, synths, tape
machines or as returns from processing units. The inputs are
BALANCED for low noise and immunity from interference, but you can
use UNBALANCED sources by wiring up the jacks as shown, although
you should then keep cable lengths as short as possible to minimise
interference pick-up.
INPUT +4/-10
Most professional equipment uses input and output levels of +4dBu,
but semi-professional tape machines or hi-fi systems use a lower level
of -10dBV. This switch allows you to match the sources connected to the Stereo input jacks to either standard,
which is important to ensure the best possible sound quality. If you are not sure what input level is appropriate,
start with the switch UP to 4dBu. If you are unable to achieve an adequate signal level, press the switch
in for -10dBV.
HF EQ
Turn to the right to boost high (treble) frequencies, adding crispness to percussion from drum machines, synths
and electronic instruments. Turn to the left to cut these frequencies, reducing hiss or excessive brilliance. Set the
knob in the centre-detented position when not required. The control has a shelving response giving 15dB of boost
or cut at 12kHz.
LF EQ
Turn to the right to boost low (bass) frequencies, adding extra punch to synths, guitars and drums. Turn to the left
to reduce hum, boominess or improve a mushy sound. Set the knob to the centre-detented position when not
required. The control has a shelving response giving 15dB of boost or cut at 60Hz.
EQ Switch
The EQ switch disables the equaliser when released and activates it when pressed. It would typically be used for
simple comparison of the equalised and unequalised signal.
AUXILIARY SENDS
These controls route the input channel signal to any one or more of eight Auxiliary busses. These combine the
sends from each channel, mixing them to separate outputs on the rear of the mixer. Since they are independent
of the main outputs they can provide additional sources for foldback, echo units or extra loudspeaker ‘fills’. The
controls are specially chosen to give a particularly smooth control range at the lower end of the scale where it is
most needed - quite unique on a mixer of this type. Leave the knobs turned anticlockwise when not in use.
AUX SEND 1 & 2
These sends are always PRE-FADE, POST EQ and are not affected by the ON switch. They would typically be
used for Foldback or Monitor feeds, for which it is important that the send should be independent of the fader so
that, for instance, the mix to artists headphones or monitor wedges is not affected by changes in fader level. They
are fed from a mono sum of the channel Left and Right signals.
AUX SEND 3
Hot (+ve)
Cold (-ve)
Gnd/Screen
Signal
Gnd/Screen
Gnd/Screen
Tip
Ring
Sleeve
Unbalanced
Balanced
16
SPIRIT FOLIO 4
