GR4 User Guide
16
AP10223 Issue_2
Setting up GR4
7.1
Operating Features
The GR4 is a feature rich analogue zone mixer.
Multiple configurations are possible by means
of internal jumpers, external dip switches and
also via digital programmable pre-sets.
The below gives an overview of the various
Modes that the GR4 enters when signal is
sensed on various input connectors.
Primary Mic Mode: When audio sensed on
Mic 1 channel and/or PAGE contact closure is
sensed then music is faded to pre-set level
and Mic 2 muted for the duration of the
announcement. Mic 1 zone select LEDs flash
slowly when in primary mic mode.
Secondary Mic Mode: When audio is sensed
on Mic 2, then music is faded to pre-set level
for the duration of the announcement. Mic 2
zone select LEDs flash slowly when in
secondary mic mode.
Emergency Mic Mode: When ALARM contact
is activated all zone feeds are muted and Mic
1 is fed direct to all zones. All select LEDs
except Mic 1 LED are switched off for the
duration. Mic 1 LED will flash quickly.
Juke Box Mode: Is a priority Music feed.
When in Jukebox mode and audio is sensed
on ST3 the current music feed will ‘duck’* to
the pre-set level. If ST3 is silent for the pre-set
period, the previous Music selection will
resume. Mic volume is not affected by
Jukebox priority.
*Pre-set levels for the above modes are
achieved via a side-chain compressor or
‘
ducker
’.
A ducker is dynamic control of Input
x by input y which has a higher priority. If audio
is detected at Input y then Input x will be
‘Ducked’ by a predetermined level which can
be set by the user (see Table 1 6.4 for user
definable parameters). In addition to the
amount of attenuation is applied to the
‘Ducked’ signal the user can also
control the
hold time and release time of the compressor
to suit the application.
