Allen&Heath GL3800 - Manual (Page 28)

28 GL3800 User Guide
Polarity Refers to the positive (+) and negative (-) wires of a
loudspeaker or balanced audio connection. The console input
channels include POLARITY switches which reverse the + and – input
connections. Some applications include correcting for reverse wired
cables, correcting for microphone placement problems, mixing two
mics on a snare drum, one above the other below where the
diaphragms move in opposite directions, and helping to reduce comb
filtering effects as radio miked actors perform close to each other.
Polarity is sometimes labelled ‘phase’ on mixing consoles.
Technically, ‘phase’ is not the correct term as it implies a 180 degree
time shift. Polarity simply reverses the wires. It does not affect time.
Before starting your mixing, check that all the channel polarity
switches are correctly set, normally up (+).
Mixing the PA in mono or stereo? Because a console
provides an L and R output does not mean you have to mix in stereo.
It is often convenient to have separate fader control, processor inserts,
and outputs to drive two mono speaker stacks in an FOH system.
How much stereo you introduce into your mix depends on where you
position the pan controls. In most situations the size of the room and
position of the speakers makes stereo mixing an advantage only for a
small section of the audience, usually those around the sound
operator! Those listening near the speakers are likely to lose
information from the opposite stack. For this reason it is best to mix
most sources in mono (pan centred). However, it can enhance the
image by mixing some ‘ambient’ sounds in stereo, for example reverb
returns, keyboards and special effects. Where the speakers are
widely placed, you can reduce the stereo image by reducing the
amount of panning to each side. Whatever image you create it is
important that you listen to the results and consider the listeners at all
positions in the room.
Zero the console Before starting the sound check it is good
practice to ‘zero’ the console by setting all its controls to a sensible
starting condition. Check that the mode switches are correctly set for
your application. Set all GAIN, EQ and PAN controls mid, FADER, AUX
and MATRIX controls off, TALKBACK and OSC/NOISE levels off, and
all switches up. Make sure the osc/noise generator is turned off. Cue
Sheets are provided at the rear of this user guide for you to copy and
log your control settings. This can also be downloaded from our web
site.
Turning the system on and off It is good practice to:
• Turn the amplifiers on last and off first.
• Mute channels before plugging cables, unplugging
instruments and switching phantom power.
• Let equipment which has been stored in a damp or cold
place acclimatise in the venue first before powering it up.
• Power up the system in plenty of time before you start the
sound check or show.
Sound levels The ear is a delicate instrument. Do not subject
yourself or any listener to long periods of loud sound, particularly with
extreme equalisation. This may result in frequency selective or full
range hearing loss. Adhere to the sound level regulations which may
apply to the venue… and common sense!
LAMP LAMP
DUAL FUNCTION AUDIO MIXING CONSOLE
GL3800
1 2 UNDER ARMREST
PHONES
5 0 -5
16 10 -20 -10 8
5 0 -5
16 10 -20 -10 8
5 0 -5
16 10 -20 -10 8
8
8
8 8 8 8 8 8 8 8 8
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MODE WEDGE P/AFL M
PK!
+6
0
SIG PK!
+6
0
SIG PK!
+6
0
SIG PK!
+6
0
SIG PK!
+6
0
SIG PK!
+6
0
SIG PK!
+6
0
SIG PK!
+6
0
SIG PK!
+6
0
SIG PK!
+6
0
SIG PK!
+6
0
SIG
MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE
MUTE GROUPS
STEREO
STEREO
MONITOR PFL/AFL
0 10
MTX1
MTX2
MTX3
MTX4
AUX
2TRK
MONITOR 9-10
L-R
M
L
2TRK REPLAY
TO LR
R
2TRK +10
+16
-6
-9
-20
-30 -16 -12 -3 0 +3 +6 +9
POWER
TALK
M
OSC/NOISE
TALKBACK
ON
MIN MAX
MIN MAX
TALKBACK MIC
L-R
LATCH
MTX1-2
MTX3-4
AUX 9-10
AUX 5-8
AUX 3-4
AUX 1-2
PINK NOISE 1kHz OSC
TO M TO M TO M TO M TO M TO M TO M GRP8 GRP7 GRP6 GRP5 GRP3 GRP4 GRP2 TO M GRP1
= PAN
L R
TO LR GRP8 = PAN
L R
TO LR GRP7 = PAN
L R
TO LR GRP6 = PAN
L R
TO LR GRP5 = PAN
L
TO LR =
R L R
TO LR GRP3 GRP4 = TO LR
R L
PAN = TO LR
R
PAN
L
GRP1 GRP2 PAN L-R TO M
0dB
MONITOR FOH AUX MODE ROTARIES
FADERS
REV
AUX 8
+10 AFL
0 AUX 7
+10 AFL
0 AUX 6
+10 AFL
0 AUX 5
+10 AFL
0 AUX 4 0
+10 AFL +10 AFL
0 0 AUX 2
+10 AFL AFL +10
1 AUX AUX 3 AUX 9-10
+10 STEREO MUTE
REV REV REV REV REV REV REV REV
0 0
M
EXT IN
+6 GRP 1
GRP
GRP
GRP
4 GRP
3
2
GRP
GRP
5
GRP
8
7
6
L
R
LEVEL
MUTE
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
+6
M
EXT IN
GRP 1
GRP
GRP
GRP
4 GRP
3
2
GRP
GRP
5
GRP
8
7
6
L
R
LEVEL
MUTE
M
EXT IN
GRP 1
GRP
GRP
GRP
4 GRP
3
2
GRP
GRP
5
GRP
8
7
6
L
R
LEVEL
MUTE
M
EXT IN
GRP 1
GRP
GRP
GRP
4 GRP
3
2
GRP
GRP
5
GRP
8
7
6
L
R
LEVEL
MUTE
PFL
+6
+6
AUX 1
AUX 2
AUX 9-10 +6
GAIN
M
1-2
L-R
GAIN
LR DIRECT TO
MUTE
30
5
20 10
0 5
ST1
ST2 STEREO
STEREO
PFL
+6
+6
AUX 1
AUX 2
AUX 9-10 +6
GAIN
M
3-4
L-R
-5 -10 -20 5 10 16
0 GAIN
LR DIRECT TO
MUTE
ST3
ST4 STEREO
STEREO DUAL STEREO RETURN DUAL STEREO RETURN
10 10
5 0
10 20
5
30 8
10 5 0
5
10
20
30 30
20
10
5
0 5 10
30
20
10
5
0 5 10
30
20
10
5
0 5 10
30
20
10
5
0 5 10
30
20
10
5
0 5 10
30
20
10
5
0 5 10
30
20
10
5
0 5 10
30
20
10
5
0 5 10
30
20
10
5
0 5 10
30
20
10
5
0 5 10
GRP8 AUX8 GRP7 AUX7 GRP6 AUX6 GRP5 AUX5 GRP4 AUX4 GRP3 AUX3 GRP2 AUX2 AUX1 GRP1 AFL AFL AFL AFL AFL AFL AFL AFL M LISTEN R L AUX9-10
POLARITY
Think before you hit
the switch!