SoundCraft Spirit Folio 4 - Manual (Page 8)

% For further detail
see page 18
e
AUX 3 PRE The input channels provide both Pre- and Post-Fade
AUX 3 sends which may be selected desk-wide on the Master
Section. Press the AUX 3 PRE switch to make all of the AUX 3
Sends on the channel strips PRE-FADE. This means that they will
all be unaffected by the position of the channel faders, making
them ideal for FOLDBACK or MONITORING.
Two Stereo Return sections each comprise a pair of
unbalanced inputs suitable for -10dBV or +4dBu sources. A
mono signal may be plugged into the Left socket only for
each pair to be fed equally to left and right busses. Each
section is provided with a routing switch to select between a
pair of Groups (switch released) or MIX (switch pressed).
Stereo Returns A & B feed Groups 1 and 2, while Returns C
& D feed Groups 3-4.