Allen&Heath GL2800M USER GUIDE - Manual (Page 13)

G G G GL L L L2 2 2 28 8 8 80 0 0 00 0 0 0M M M M 13 Allen & Heath
The Mix Master
OUTPUT EQ (MIX 1-8 only) 2 band swept frequency peak/dip EQ
with in/out switch. Use this to adjust the overall sound of the mix, for
example to satisfy the preference of a performer using in-ears, or to
notch out wedge speaker feedback when an outboard EQ is not
available.
POLARITY Reverses the signal +/- polarity of the output. Start
with the switch in its up (non-inverted) position. Pressing the switch
for reversed polarity can help in situations where speaker wiring
errors, phasing effects or feedback is experienced on stage. Use the
console pink noise generator to help identify speaker polarity and
interaction problems.
HPF Swept frequency 12dB/octave high pass (low cut) filter
affecting the mix output. Adjust from off (full response) to 400Hz.
Cutting the low frequency response of wedge monitor speakers can
help clean up the stage sound and avoid wasting amplifier power on
low end sounds and bleed not needed in the monitors.
TB Enables the talkback / oscillator to the mix output. You can talk
to or route the oscillator/noise generator to any combination of mix
outputs using these switches.
MUTE Turns off the mix output. Affects the meter but does not
affect the mix AFL function.
DIM This momentary switch lets you attenuate the mix output level
by 6dB (half volume) while holding it pressed. This can help you
quickly identify and stop a monitor speaker feedback, or reduce
volume without moving the fader while you are talking to a performer
on stage.
AFL Routes the post-fade pre-mute mix output to the engineer’s
monitor system. Depending on the configuration of the GLOBAL
SETTINGS switches, AFL feeds the console headphones monitor and
either the engineer’s wedge speaker or the IEM (in-ear) monitor
output. The associated yellow LED indicates which monitor is being
fed. If two mixes are configured as a stereo pair, pressing one AFL
checks that mix in mono, and pressing both AFL together checks the
mix in stereo in the headphones and IEM monitors.
METER 12 LED bar output meter displays the signal at the mix
output XLR. Meter ‘0’ = XLR +4dBu output.
STEREO INDICATOR Green LED lights when the pair of mixes
have been configured for stereo operation using the GLOBAL
SETTINGS switches. In stereo mode, the associated channel sends
operate as level and pan controls, and AFL can provide L only, R only
or stereo LR checking of the mix.
FADER A 100mm fader provides accurate control of the mix output.
INSERT Each mix is provided with an insert socket for patching in
an outboard signal processor. When working with stage speakers this
is typically a 31 band graphic or a multi band parametric EQ used for
ringing out feedback or tuning the speaker response. When working
with in-ear systems this may be a dynamics processor with limiter to
protect the ears of the IEM user. AFL monitors the signal after the
insert so that the engineer can listen to the effect of the processor. A
single 3-pole TRS jack carries the unbalanced insert signal for each
mix output. Tip = send, Ring = return, Sleeve = common ground.
The insert is post-HPF and pre-EQ, pre-fader and operates at a
nominal -2dBu line level.
- +
EQ IN
MUTE
EQ IN
DIM
TB
POLARITY POLARITY
MUTE
DIM
TB
LM
80Hz 2k
HM
500Hz 12k
9K
6k
4k
3K 2k
1k
700
1k
700
500
400
200
100
- +
- +
LM
80Hz 2k
HM
500Hz 12k
9K
6k
4k
3K 2k
1k
700
1k
700
500
400
200
100
- +
+9
+6
+3
0
-3
-12
-16
-30
-20
-9
-6
+16
0
5
10
20
30
10
5
0 0
STEREO
10
20
30
0 0
0
10
5
5
WEDGE
IEM
AFL
WEDGE
IEM
AFL
1 2
15
50
40 100
200
HPF
off 400
15
50
40 100
200
HPF
off 400