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USO RESTRITO
ALLEN&HEATH
GL2800
USER GUIDE
Publication AP6095
Limited One Year Warranty
This product is warranted to be free from defects in materials or workmanship for
a period of one year from the date of purchase by the original owner.
USO RESTRITO
To ensure a high level of performance and reliability for which this equipment has
been designed and manufactured, read this User Guide before operating. In the
event of a failure, notify and return the defective unit to Allen & Heath Limited or
its authorised agent as soon as possible for repair under warranty subject to the
following conditions
Conditions Of Warranty
1. The equipment has been installed and operated in accordance with the
instructions in this User Guide
2. The equipment has not been subject to misuse either intended or accidental,
neglect, or alteration other than as described in the User Guide or Service
Manual, or approved by Allen & Heath.
3. Any necessary adjustment, alteration or repair has been carried out by Allen
& Heath or its authorised agent.
4. This warranty does not cover fader wear and tear.
5. The defective unit is to be returned carriage prepaid to Allen & Heath or its
authorised agent with proof of purchase.
6. Units returned should be packed to avoid transit damage.
In certain territories the terms may vary. Check with your Allen & Heath agent for
any additional warranty which may apply.
This product complies with the European Electromagnetic
Compatibility directives 89/336/EEC & 92/31/EEC and the
European Low Voltage Directives 73/23/EEC & 93/68/EEC.
This product has been tested to EN55103 Parts 1 & 2 1996 for use in
Environments E1, E2, E3, and E4 to demonstrate compliance with the
protection requirements in the European EMC directive 89/336/EEC.
During some tests the specified performance figures of the product
were affected. This is considered permissible and the product has
been passed as acceptable for its intended use. Allen & Heath has a
strict policy of ensuring all products are tested to the latest safety and
EMC standards. Customers requiring more information about EMC
and safety issues can contact Allen & Heath.
NOTE: Any changes or modifications to the console not approved by
Allen & Heath could void the compliance of the console and therefore
the user’s authority to operate it.
GL2800 User Guide AP6095 Issue 3
Copyright © 2006 Allen & Heath Limited. All rights reserved
ALLEN&HEATH Limited
Kernick Industrial Estate, Penryn, Cornwall, TR10 9LU, UK
http://www.allen-heath.com
2
GL2800 User Guide
USO RESTRITO
Important Safety Instructions
WARNINGS -
Read the following before proceeding :
CAUTION
ATTENTION: RISQUE DE CHOC ELECTRIQUE – NE PAS OUVRIR
Read instructions:
Read and retain these safety and operating
instructions for future reference. Adhere to all warnings printed here and
on the console. Follow the operating instructions printed in this User
Guide.
Do not remove cover: Operate the console and power units with
their covers correctly fitted. Disconnect mains power by unplugging the
power cord if the cover needs to be removed for setting internal options.
Refer this work to competent technical personnel only.
Power sources: Connect the console to a mains power outlet only
of the type described in this User Guide and marked on the rear panel.
Use the power cord with sealed mains plug appropriate for your local
mains supply as provided with the console. If the provided plug does not
fit into your outlet consult your service agent for assistance.
Power cord routing:
Route the power cord so that it is not likely
to be walked on, stretched or pinched by items placed upon or against it.
Grounding:
Do not defeat the grounding and polarisation
means of the power cord plug. Do not remove or tamper with the ground
connection in the power cord.
WARNING: This equipment must be earthed.
Water and moisture:
To reduce the risk of fire or electric shock
do not expose the console or its power units to rain or moisture or use in
damp or wet conditions. Do not place containers of liquids on surfaces
where liquid may spill into any openings.
Ventilation:
Do not obstruct the power supply heatsinks and
ventilation slots or position the console where the air flow required for
ventilation is impeded. If the console is to be operated in a flight case,
plinth or other furniture ensure that it is constructed to allow adequate
ventilation.
Heat and vibration:
Do not locate the console in a place
subject to excessive heat or direct sunlight as this could be a fire hazard.
Locate the console away from any equipment which produces heat or
causes excessive vibration.
Servicing:
Switch off the equipment and unplug the power
cord immediately if it is exposed to moisture, spilled liquid, objects fallen
into the openings, the power cord or plug become damaged, during
lightning storms, or if smoke, odour or noise is noticed. Refer servicing to
qualified technical personnel only.
Installation:
Install the console in accordance with the
instructions printed in this User Guide. Do not connect the output of
power amplifiers directly to the console. Use audio connectors and plugs
only for their intended purpose.
GL2800 User Guide
3
General Precautions
Damage
To prevent damage to the controls and cosmetics avoid
placing heavy objects on the control surface, scratching the surface with
sharp objects, or rough handling and vibration.
Environment Protect from excessive dirt, dust, heat and vibration
when operating and storing. Avoid tobacco ash, smoke, drinks spillage,
and exposure to rain and moisture. If the console or its power unit
becomes wet, switch off and remove mains power immediately. Allow to
dry out thoroughly before using again.
Cleaning
USO RESTRITO
Avoid the use of chemicals, abrasives or solvents. The
control panel is best cleaned with a soft brush and dry lint-free cloth. The
faders, switches and potentiometers are lubricated for life. The use of
electrical lubricants on these parts is not recommended. The fader and
potentiometer knobs may be removed for cleaning with a warm soapy
solution. Rinse and allow to dry fully before refitting them.
Lifting To avoid injury to yourself or damage to the equipment take
care when lifting, moving or carrying the console.
Transporting
The console may be transported as a free-standing
unit or mounted in a purpose built flight case. We recommend that the
console is surrounded by shock absorbent foam to protect it from
damage during transit. Always use adequate packing if you need to ship
the unit. Protect the controls to avoid damage when moving the console.
Hearing To avoid damage to your hearing do not operate any sound
system at excessively high volume. This also applies to any close-to-ear
monitoring such as headphones and IEM transducers. Continued
exposure to high volume sound can cause frequency selective or wide
range hearing loss.
Important Mains plug wiring instructions.
The console is supplied with a moulded mains plug fitted to the AC
mains power lead. Follow the instructions below if the mains plug has
to be replaced. The wires in the mains lead are coloured in
accordance with the following code:
TERMINAL
WIRE COLOUR
European
USA/Canada
L
LIVE
BROWN
BLACK
N
NEUTRAL
BLUE
WHITE
E
EARTH GND
GREEN & YELLOW
GREEN
The wire which is coloured Green and Yellow must be connected to
the terminal in the plug which is marked with the letter E or with the
Earth symbol. This appliance must be earthed.
The wire which is coloured Blue must be connected to the terminal in
the plug which is marked with the letter N.
The wire which is coloured Brown must be connected to the terminal
in the plug which is marked with the letter L.
Ensure that these colour codes are followed carefully in the event of
the plug being changed.
4
GL2800 User Guide
USO RESTRITO
Introduction
Welcome to the Allen & Heath GL2800, the latest generation of the popular GL series of
dual function live sound mixing consoles. We have tried to keep this user guide brief and to
the point. Please read it fully before starting. Included is information on installing,
connecting and operating the console, panel drawings, system block diagram and
technical specification. For further information on the basic principles of audio system
engineering, please refer to one of the specialist publications and resources available from
bookshops, audio equipment dealers and the Internet.
Whilst we believe the information in this guide to be reliable we do not assume
responsibility for inaccuracies. We also reserve the right to make changes in the interest of
further product development.
We are able to offer further product support through our world-wide network of approved
dealers and service agents. You can also access our Web site on the Internet for
information on our full product range, resource downloads, our company pedigree, contact
details, assistance with your technical queries, or simply to chat about audio. To help us
provide the most efficient service please keep a record of your console serial number, and
date and place of purchase to be quoted in any communication regarding this product.
http://www.allen-heath.com
http://www.glseries.com
Contents
Warranty.................................................2
Important Safety Instructions ................3
General Precautions ..............................4
Introduction to this Guide......................5
Gain Structure.................................................. 25
Panel Layouts ........................................6
Using the Oscillator / Noise Generator ........... 26
Introducing the GL2800....................8
Mixing with Faders or Gain Controls............... 26
Installing the Console ..........................10
Using PFL / AFL ............................................... 27
The dB.............................................................. 27
Connecting Power ...............................11
Using Inserts .................................................... 27
Audio Connections ..............................13
Polarity ............................................................. 28
Mixing the PA in Mono or Stereo? .................. 28
The Console Connectors ....................14
Zero the console.............................................. 28
Mono Input Channel ............................16
Turning the System On or Off ......................... 28
Sound Levels ................................................... 28
Stereo Input Channel...........................18
Dual Functionality ............................................ 29
Stereo Return Channel ........................19
Applications for the Matrix............................... 30
Create IEM Mixes with Ambience ................... 31
Group/Aux Masters..............................20
Using the Matrix to Create a Recording.......... 31
Mute, Aux 9-10 and L-R-M Masters.....21
Recording with the GL2800............................. 31
Pre/Post Fade Aux Settings ............................ 31
Mix and Aux-Fed Subs .................................... 32
Other M Output Applications........................... 32
Using the Channel Direct Outputs .................. 32
Using the Stereo Channels ............................. 33
A Note about Combining Signals ................... 33
12x4 Matrix...........................................22
2-Track Replay and Console Monitor .23
Talkback and Signal Generator ..........24
Applications and Operating Tips.........25
Specifications ......................................34
System Block Diagram ........................36
User Options........................................37
Cue Sheets ..........................................40
GL2800 User Guide
5
GL2800
+48V
+48V
+48V
+48V
POLARITY
POLARITY
POLARITY
POLARITY
LINE
0
20
30
LINE
LINE
(PAD)
(PAD)
0
40
GAIN
50
20
30
LINE
(PAD)
0
40
GAIN
50
20
30
DUAL STEREO RETURN
(PAD)
0
40
GAIN
50
20
30
STEREO
GAIN -5
40
GAIN
0
5
-10
50
6
60 40
-14
60 40
6
HPF
-15
1k
HM
-15
1k
6k
500Hz
15k
500Hz
HF
-15
180
45
35Hz
1k
-15
LF
70
+15
80Hz
LM
+15
-15
+6
5
AUX
+6
OO
AUX
+6
OO
AUX
8
AUX
STEREO
+6
=
PAN
OO
L
R
L
R
EVEN
L
ODD
+6
=
AUX
0
1
5
3-4
OO
+6
10
7-8
5-6
30
M2
M1
30
M3
M4
10
5
00
M3
M4
4
AUX
0
5
AUX
0
6
AUX
0
7
AUX
9-10
AUX
8
9-10
+10
OO
+10
OO
+10
+10
OO
OO
+10
+10
OO
+10
OO
+10
OO
REV
REV
REV
AUX
GRP1
TO M
GRP2
TO M
GRP3
TO M
GRP4
TO M
GRP5
TO M
GRP6
TO M
GRP7
TO M
GRP8
TO M
STEREO
GRP1
TO LR
GRP2
TO LR
GRP3
TO LR
GRP4
TO LR
GRP5
TO LR
GRP6
TO LR
GRP7
TO LR
GRP8
TO LR
OO
MUTE
MONITOR
+10
MUTE GROUPS
REV
POST
PRE
OO
+6
=
=
=
PAN
L
R
=
PAN
L
R
=
PAN
L
R
=
PAN
L
R
=
PAN
L
R
=
PAN
L
R
L
R
L-R TO M
=
PAN
PAN
L
R
L
R
OO
WEDGE
MODE
0dB
POST
PRE
PK!
+6
0
SIG
L
ODD
PK!
+6
0
SIG
PK!
+6
0
SIG
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
R
EVEN
MUTE
MUTE
AFL
MUTE
AFL
MUTE
AFL
GRP2
AUX1
AFL
GRP3
AUX2
MUTE
AFL
GRP4
AUX3
MUTE
AFL
GRP5
AUX4
MUTE
AFL
GRP6
AUX5
MUTE
AFL
GRP7
AUX6
MUTE
GRP8
AUX7
L
AUX8
AUX9-10
R
M
10
10
10
10
10
10
10
10
10
10
10
10
5
5
5
5
5
5
5
5
5
5
5
5
0
0
0
0
0
0
0
0
0
0
0
0
5
5
5
5
5
5
5
5
5
5
5
5
10
10
10
10
10
10
10
10
10
10
10
10
20
20
20
20
20
20
20
20
20
20
20
20
30
30
30
30
30
30
30
30
30
30
30
30
00
00
00
00
00
00
00
00
00
00
00
00
1-2
3-4
10
5-6
7-8
30
M1
M2
00
M3
M4
1
6
MTX2
L-R
M2
M2
00
M1
3
AUX
0
REV
20
20
AUX
0
REV
R
EVEN
7-8
7-8
20
MTX1
STEREO
MUTE
REV
5
5-6
2TRK
=
3-4
10
MUTE
REV
0
5
MUTE
REV
BAL
1-2
3-4
L-R
AUX
9-10
+6
OO
AFL
R
L
ODD
0
+6
OO
AFL
POST
PRE
L-R
1-2
AUX
0
2
GRP1
5
+6
OO
AFL
PFL
L-R
AUX
5-8
LATCH
AFL
PFL
5
+6
10
M
MTX4
AUX
BAL
L
M
+6
OO
LEVEL
AFL
=
10
+6
OO
LEVEL
AFL
PFL
M
+6
OO
LEVEL
+6
OO
M
AFL
PFL
10
+6
OO
LEVEL
+6
OO
M
AFL
MUTE
0
M4
+6
MUTE
1-2
M3
OO
PK!
+6
0
SIG
+6
OO
M
0
AUX
3-4
STEREO
OO
OO
MUTE
PK!
+6
0
SIG
R
STEREO
MUTE
L-R
M1
STEREO
R
EVEN
30
OO
9-10
BAL
L
ODD
+6
OO
M
MUTE
+6
OO
POST
PRE
=
PAN
R
8
POST
PRE
=
+6
MTX3
+6
OO
R
30
OO
AUX
BAL
POST
PRE
PAN
5-6
+6
=
OO
AUX
1-2
+6
OO
R
+6
+6
OO
+6
AUX
PAN
20
+6
OO
OO
L
TALK
7
9-10
STEREO
20
MTX3-4
+6
OO
L
+6
OO
AUX
POST
PRE
9-10
5
+6
OO
R
3-4
POST
PRE
+6
8
AUX
9-10
+6
OO
10
PFL/AFL
8
6
OO
+6
POST
PRE
+6
GRP
8
L
0
5
+6
OO
GRP
AUX
AUX
OO
OO
L-R
5
OO
+6
8
+6
OO
+6
7
MONITOR
L
10
+6
OO
8
+6
OO
+6
OO
7
OO
OO
GRP
7
AUX
AUX
AUX
+6
OO
GRP
GRP
+6
OO
POST
PRE
+6
OO
7
M
6
+6
OO
+6
6
AUX
7
+6
OO
+6
OO
L-R
1-2
4
OO
R
+16
+9
+6
+3
0
-3
-6
-9
-12
-16
-20
-30
+6
OO
GRP
6
L
ON
+6
OO
7
OO
5
0
AUX
AUX
6
L-R
+6
OO
+6
5
AUX
6
MAX
PINK NOISE
1kHz OSC
5
GRP
GRP
8
M
3
OO
+6
OO
+6
GRP
10
M
AUX
AUX
5
+6
6
7
PFL
5
+6
POST
PRE
+6
OO
+6
GRP
5
OO
GRP
MUTE
10
2
OO
+6
AUX
OO
+6
OO
PFL
+15
EQ IN
AUX
4
POST
PRE
AUX
+6
MTX1-2
-15
+6
AUX
OO
OO
POWER
+6
GRP
GRP
OO
1
OO
+6
OO
+6
OO
MUTE
AUX
3
4
OO
+15
2TRK
TO LR
4
OO
5
GRP
+15
EQ IN
AUX
AUX
-15
+6
+10
OO
GRP
4
GRP
6
+6
+6
OO
MAX
OSC/NOISE
+6
OO
AUX
9-10
OO
MIN
3
GRP
OO
GRP
+6
AUX
+6
OO
GRP
80Hz
-15
PRE-EQ
+6
OO
4
+15
LF
2
3
2
9-10
+15
AUX
AUX
AUX
-15
LF
+6
PRE-EQ
3
250Hz
1
OO
-15
250Hz
AUX
2
AUX
+15
+6
2TRK REPLAY
TALKBACK
MIN
+6
OO
5
LM
+15
AUX
2
2
+6
OO
4
+6
2
3
GRP
OO
GRP
GRP
OO
GRP
+6
+6
OO
AUX
OO
-15
+6
OO
1
+6
OO
AUX
LM
EQ IN
+6
OO
2k5
80Hz
-15
1
AUX
M
+15
AUX
1
2k5
400
1k
EQ IN
AUX
PK!
+6
0
SIG
250
35Hz
LF
HM
+15
+6
OO
+6
OO
OO
1
2
3
PHONES
TALKBACK MIC
GRP
GRP
GRP
4
-15
HM
+6
OO
AUX
+6
OO
2
3
+6
OO
1
GRP
GRP
16
OO
12k
+15
+15
80Hz
-15
OO
180
45
400
USO RESTRITO
LM
-15
250
10
-20
1
12k
+15
10
+6
OO
2
EXT
IN
GRP
1
GRP
-10
AUX
15k
LR
ST4
5
+6
OO
GRP
1
0
EXT
IN
+6
GRP
DIRECT TO
STEREO
GAIN -5
16
OO
HF
-15
70
LR
ST2
5
-20
16
OO
0
-10
5
-30
16
OO
6k
STEREO
GAIN -5
0
EXT
IN
OO
10
16
OO
DIRECT TO
100Hz
-20
5
-30
3k +15
4k
700
HM
0
-5
EXT
IN
ST3
5
-20
16
OO
HPF
STEREO
GAIN-10
-5
-20
3k +15
4k
700
60 40
6
100Hz
STEREO
GAIN-10
12k
-14
HPF
100Hz
HF
12k
60 40
6
HPF
100Hz
HF
-14
0
-10
10
-20
-14
DUAL STEREO RETURN
STEREO
GAIN -5
ST1
2
3
4
5
6
7
8
L
R
GL2800 User Guide
M
LISTEN
USO RESTRITO
The Range:
LAMP
OUT
OUT
R (10)
M (WEDGE)
22 mono mic/line, 2 mic/ stereo line, 2 dual stereo returns
GL2800-32
30 mono mic/line, 2 mic/ stereo line, 2 dual stereo returns
GL2800-40
38 mono mic/line, 2 mic/ stereo line, 2 dual stereo returns
GL2800-48
46 mono mic/line, 2 mic/ stereo line, 2 dual stereo returns
GL2800-56
54 mono mic/line, 2 mic/ stereo line, 2 dual stereo returns
RPS11
Power Supply
GL2800-SLV2
Sys-Link V2 console in/out expander option kit
MIC OUT
MIC OUT
(BREAKPOINT)
(BREAKPOINT)
DIRECT
OUT
DIRECT
OUT
DIRECT
OUT
DIRECT
OUT
DIRECT
OUT
DIRECT
OUT
INSERT
INSERT
INSERT
INSERT
INSERT
INSERT
LINE IN
LINE IN
LINE IN
LINE IN
LINE IN
LINE IN
MIC IN
MIC IN
MIC IN
MIC IN
MIC IN
MIC IN
MATRIX EXT IN
L
2TRK
L/M
R
R
OUT
MONITOR
OUT
R
GL2800-24
IN
ST4 IN
(COMMON)
MTX
IN
4
MTX
IN
3
MTX OUT
4
MTX
IN
2
MTX OUT
3
MTX
IN
1
MTX OUT
2
L/M
MTX OUT
1
ST3 IN
L/M
ST1 IN
ST2 IN
L/M
STEREO LINE IN
L/M
STEREO LINE IN
L/M
L/M
LAMP
R
R
R
MIC IN
L
TB/GEN
OUT
INSERT
M
INSERT
R
INSERT
L
INSERT
8
INSERT
7
INSERT
6
INSERT
5
INSERT
4
INSERT
3
INSERT
2
INSERT
1
AUX (R)
10
AUX (L)
9
AUX (GRP)
8
AUX (GRP)
7
AUX (GRP)
6
AUX (GRP)
5
AUX (GRP)
4
AUX (GRP)
3
AUX (GRP)
2
AUX (GRP)
1
MIC IN
INPUT
SEND
INSERT
(GRP/AUX REVERSE)
OUT
L (9)
GRP (AUX) 8
GRP (AUX) 7
GRP (AUX) 6
GRP (AUX) 5
GRP (AUX) 4
GRP (AUX) 3
GRP (AUX) 2
GRP (AUX) 1
RING
RETURN
DC POWER IN
DC POWER IN
B (BACKUP)
A
1
2
USE ONLY THE RECOMMENDED
ALLEN & HEATH POWER SUPPLY
TIP
3
TIP +IN
RING -IN
+IN
MIC
- IN
SERIAL NUMBER
LINE
ALLEN & HEATH LIMITED
DIRECT
OUT
DIRECT
OUT
DIRECT
OUT
DIRECT
OUT
DIRECT
OUT
DIRECT
OUT
DIRECT
OUT
DIRECT
OUT
INSERT
INSERT
INSERT
INSERT
INSERT
INSERT
INSERT
INSERT
LINE IN
LINE IN
LINE IN
LINE IN
LINE IN
LINE IN
LINE IN
LINE IN
MIC IN
MIC IN
MIC IN
MIC IN
MIC IN
MIC IN
MIC IN
MIC IN
SYS-LINK V2 CONSOLE EXPANDER INPUT ( option )
INPUT A
GL2800 User Guide
INPUT B
7
Introducing the Allen & Heath GL2800
USO RESTRITO
The GL2800 is an 8-bus dual function analogue mixing console designed for
professional audio applications. Whether mixing FOH, monitors or both, recording live or in
the studio, installed in a busy venue, out on the road touring, or earning its keep in rental
stock, the GL2800 provides the perfect solution. Engineered to the same exacting
standards as our top of the range consoles it ensures the highest reliability and finest sonic
performance. We have taken the outstanding success of our industry leading GL consoles
and provided yet more innovative capability and enhanced performance for modern mixing.
8
•
24, 32, 40, 48, 56 channel frames
•
L, R and M mix buses
•
8 audio groups with pan and routing to LR and M
•
10 Auxes including a dedicated stereo send
•
12x4 matrix with full stereo capability
•
2 Stereo channels each with mic and stereo line inputs
•
2 extra dual stereos provide 4 summed or independent stereo returns
•
Proper dual functionality for FOH/monitor mixing
•
M can be used for centre, mono sum or sub, or for engineers monitor wedge
•
Recording capable with channel direct outputs
•
Matrix external inputs with level trim and common input capability
•
Stereo channel mic can cross patch into matrix for ambience
•
Dual stereo return line inputs can be independently routed to LR
•
Responsive 4 band, 2 sweep EQ
•
100Hz channel high pass filters
•
Individual phantom power and polarity switching
•
Wide angle 4 led channel meters
•
Per channel pre/post fader aux switching for unlimited flexibility
•
Recessed pre/post-EQ aux switching per channel, no internal access needed
•
Internal pluggable jumpers for pre/post-EQ aux and direct out
•
Mutes and meters on all fader masters
•
Assignable talkback to all outputs
•
1kHz oscillator / pink noise generator with external output
•
2 Track monitoring and replay to LR
•
3 Headphones sockets including 3.5mm for IEM
•
Dedicated stereo monitor meters
•
Electronically balanced XLR outputs with +26dBu drive capability
•
Preamp 74dB gain range and +34 maximum input capability
•
Ultra low noise mix head amp design
•
Uses external linear power supply
•
Built-in combiner for redundant power supply
•
Metal jacks, gold plated XLRs, sealed pots and switches
•
Individual circuit card assembly with nutted pots
•
Solid copper bus grounding
•
Sys-Link V2 console linking option
•
4-pin XLR lamp sockets
GL2800 User Guide
USO RESTRITO
Here are just a few key points we considered when specifying the GL2800:
Affordability We understand your need to work within a realistic budget and know you
want to get the very best return for your investment. We know too that even the lowest
budget shows put the same tough demands on the operator who wants the reassurance of
continued reliability and intuitive control, the satisfaction of achieving that special sound,
and the functionality to deal with the trickiest situations. We have avoided the temptation of
designing in costly plastic trims and needless external add-ons for styling only. Instead we
have invested every penny of our budget into parts that make a real difference in improving
performance, durability and flexibility of use, whether the comfortable soft feel armrest, the
practically shaped space saving steel chassis, the wide viewing angle meter design, the
exceptional feature set, or the ‘under the bonnet’ engineering such as the solid copper
grounding strip, individual cards, circuit enhancements and more. The result is a nononsense, durable mixing tool right for its application… a sensible investment.
Reliability Without doubt, the most important quality for any equipment intended for the
professional application. The GL2800 uses the well proven and long term serviceable
Allen & Heath method of individual channel card construction with every potentiometer
nutted to the front panel, a solid steel chassis with rigid beam front extrusion, 100mm
smooth travel faders with protective dust covers, metal bodied jacks and gold-plated
Neutrik XLRs, and sealed Alps pots and switches to ensure you can mix with confidence
show after show. The external linear power supply has plenty of overhead. You can even
plug in a second supply as a backup for added security.
Performance The GL2800 benefits from our latest circuit developments which have
improved the sound and responsiveness of the mic preamp and EQ, and achieved
astonishingly low residual noise from the mix head amp and output stages, crucial when
mixing into modern high powered speaker systems. The new mic preamp maintains ultra
low distortion and can accept as much as+34dBu to deal with the hottest signal you are
ever likely to plug in. The XLR outputs provide proper differential drive up to a massive
+26dBu to work with the longest and most hostile cable environments. Extensive listening
evaluation together with solid engineering practice have ensured the console achieves
accurate sound reproduction under all conditions.
Capability We know a thing or two about ‘Dual Functionality’ having pioneered this
innovative feature back in the early 90’s. The GL2800 takes this an important stage
further with its new multiple stereo mix capability. Tamperproof recessed switches
configure the console safely for optimum FOH or stage monitor operation, or for mixing
monitors from FOH. In FOH mode you get 3 main mix buses L, R and M. You can use M to
feed the C in an LCR system, to create a mono fill by summing L and R, or even drive a
sub-bass speaker system. In MONITOR mode the ‘M’ fader becomes the engineer’s
monitor wedge control, you get all 10 aux masters available on faders with mutes, inserts,
meters and electronically balanced XLR drive, and you still get the 8 subgroups to LRM,
and the groups/LRM feeding the matrix for yet more mixes. The fully featured 12x4 matrix is
a valuable addition. For example, in FOH mode you can create independent fill speaker
and acoustics compensated recording feeds, even capturing the atmosphere by cross
patching the stereo channel mic preamps into the matrix to add individual or common
mono or stereo ambience signals. In MONITOR mode the matrix gives you more monitor
outputs easily created from the groups and LR with added ‘more me’ and ambience for the
in-ear application. This compact console can feed up to 14 independent mixes, for
example 8 wedges and 3 true stereo IEM. We have also considered the RECORDING
application with direct outputs on all mono channels, 8 groups, matrix and not least the
studio quality analogue mic preamps and EQ. Whatever your application you get full
control with nothing wasted.
Attention to detail In true Allen & Heath form, every detail has been meticulously
thought through. Take for example, the compact, no frills chassis that gives you a seat
saving, flight case convenient footprint, the provision of individual channel rather than
restrictive global pre/post aux switching, comprehensive talkback, the built-in tone/pink
noise generator for system checking, full channel and main output metering, the multifunctional stereo channel and return strips, Sys-Link V2 console expansion… and much
more. We hope you enjoy being as creative using the GL2800 as our team enjoyed
creating it.
Carey Davies, Head of Design, and sound guy too…
GL2800 User Guide
9
Installing the Console
The GL2800 has a space saving, compact chassis design. This is convenient both in
saving seats for the paying audience in a busy venue, and in reducing the size, complexity
and weight of flight casing for on-the-road use. The control surface has a 10 degree slope
for optimum visibility during operation. The rear connector panel has a split angle design
for ease of plugging and unplugging the connectors.
Free Standing The console has rubber feet fitted for free standing operation on a flat
surface. Make sure the surface is well supported, stable and big enough for the console to
sit securely on all its feet. Allow enough space behind the console for access to its
connectors.
USO RESTRITO
Flight Casing The console is shaped for easy flight casing. Make sure it is supported
on all sides using suitably thick, shock absorbent foam intended for this purpose. Ensure
no part of the case or its lid touches the controls or connectors. If you include a rear
‘doghouse’ to house the connections make sure the cables can be supported in a way that
prevents putting stress on the console connectors. To prevent transit damage through
inadequate protection, we recommend you have the flight case supplied or approved by a
professional, specialist equipment case manufacturer.
Do not obstruct the heatsinks or ventilation openings on the power unit. Ensure
adequate air flow around its surfaces. To avoid audible hum, buzz or other
performance degradation, do not place equipment that radiates strong
electromagnetic fields such as the power unit, other mains power supplies, amplifiers
and computers next to or directly underneath the console.
5
9
58
640
19
62
168
634
GL2800-824 = 944
GL2800-832 = 1171
GL2800-840 = 1398
GL2800-848 = 1625
GL2800-856 = 1852
MONO
INPUTS x 8
10
MONO
INPUTS x 8
MONO
INPUTS x 8
MONO I/P x 6
ST I/P x 2
MASTER
SECTION
MONO
INPUTS x 8
MONO
INPUTS x 8
MONO
INPUTS x 8
GL2800 User Guide
650
USO RESTRITO
Connecting Power
USE ONLY THE RECOMMENDED
ALLEN & HEATH POWER SUPPLY
DC POWER IN
DC POWER IN
B (BACKUP)
A
POWER
DC FUSES
V+
ON
OFF
CAUTION: FOR CONTINUED PROTECTION AGAINST RISK OF FIRE
REPLACE FUSE WITH SAME TYPE AND RATING.
ATTENTION: REMPLACER LE FUSIBLE AVEC UN DES MEMES
CARACTERISTIQUES.
T 10A 250V 20mm
V-
Read and understand the Important Safety Instructions printed at the start of this guide,
and the warnings printed on the rear of the console. Check that your local mains supply
voltage is the same as that marked on the rear of the RPS11 power unit. Check that the
correct mains lead with moulded plug has been supplied. Make sure that the IEC mains
plug is pressed fully into the panel socket on the RPS11 before switching on.
Grounding
The connection to ground in an audio system is important for two reasons:
1.
SAFETY - To protect the operator from high voltage electric shock, and
2. AUDIO PERFORMANCE - To minimise the effect of ground (earth) loops which result in
audible hum and buzz, and to shield the audio signals from interference.
For safety it is important that all equipment grounds are connected to mains ground so that
exposed metal parts are prevented from carrying high voltage which can injure or even kill
the operator. Do not disconnect the ground connection in the mains lead. It is
recommended that the system engineer check the continuity of the safety ground from all
points in the system including microphone bodies, turntable chassis, equipment cases,
rack metalwork and so on.
Connecting the power supply
Connect the DC power lead between the socket labelled “DC OUT” on the RPS11 and the
socket labelled “DC POWER IN A” on the GL2800.
Switching the console on and off
It is good practice to turn power amplifiers off before switching the console and any other
connected equipment on or off. This prevents any unexpected clicks or thumps when the
equipment is powered up.
Turn amplifiers and powered speakers on last and off first.
Turn the console on and off using the power switch on the front of the RPS11 (there is no
separate ON/OFF switch on the console itself). The blue power indicator LED on the
console front panel will illuminate to show that the console is switched on.
Connecting a backup supply
A second power socket, labelled “DC POWER IN B (BACKUP)” is included for plugging in
an optional backup power supply. This provides the reassurance of power supply dual
redundancy, a feature usually found only on expensive top end consoles. The console
uses diode combining technology so that both supplies can be powered at the same time.
One will automatically take over should the other be switched off or stop working. The
recommended backup supply for the GL2800 is a second RPS11.
Only use the recommended Allen & Heath power supply unit. Do not attempt to
modify any other power unit to work with the console. Do not attempt to modify or extend
the DC power cable that comes with the supply.
GL2800 User Guide
11
12
19 0V (CHS)
18 L+
17 R+
16 GRP 1+
15 GRP 2+
14 GRP 3+
13 GRP 4+
12 AUX 1+
11 AUX 2+
10 AUX 3+
9 AUX 4+
8 AUX 5+
7 AUX 6+
6 PFL+
5 AFL+
4 nc
3 PFL DC
2 AFL DC
1 0V (PAFL)
19 0V (CHS)
18 M+
17 nc
16 GRP 5+
15 GRP 6+
14 GRP 7+
13 GRP 8+
12 AUX 7+
11 AUX 8+
10 AUX 9+
9 AUX 10+
8 nc
7 nc
6 nc
5 nc
4 nc
3 nc
2 nc
1 nc
L- 37
R- 36
GRP 1- 35
GRP 2- 34
GRP 3- 33
GRP 4- 32
AUX 1- 31
AUX 2- 30
AUX 3- 29
AUX 4- 28
AUX 5- 27
AUX 6- 26
PFL- 25
AFL- 24
nc 23
nc 22
nc 21
nc 20
M- 37
nc 36
GRP 5- 35
GRP 6- 34
GRP 7- 33
GRP 8- 32
AUX 7- 31
AUX 8- 30
AUX 9- 29
AUX 10- 28
nc 27
nc 26
nc 25
nc 24
nc 23
nc 22
nc 21
nc 20
XLR male plug
XLR female plug
1
3
2
2
3
1
TRS jack plug
TS jack plug
Tip
Sleeve
Ring
Tip
Sleeve
USO RESTRITO
RCA phono jacks
BALANCED
Female XLR plug
BALANCED
A
OUTPUT
INPUT
XLR male socket
XLR female socket
1
2
PIN 2 = HOT
3
Sleeve=ground
Ring=cold Tip=hot +
2
1=ground 2=hot +
3=cold -
SYS-LINK V2 OPTION
1+3 = 12V
1
UNBALANCED
INPUT / OUTPUT
link Ring to Sleeve
1
2=hot + 1=ground
UNBALANCED
3
LAMP
4 = 0V
3
BALANCED
3=cold XLR male plug
UNBALANCED
HEADPHONES
Sleeve=ground
Ring=RIGHT
Tip=LEFT
INSERT
UNBALANCED
Sleeve=ground
Ring=return
Tip=send
B
GL2800 User Guide
USO RESTRITO
Audio Connections
The GL2800 uses professional grade 3 pin XLR and 1/4" TRS (3 pole) jack sockets. To
ensure best performance, we recommend that you use high quality audio cables and
connectors, and take time to check for reliable and accurate cable assembly. It is well
known that most audio system problems are due to faulty or sub standard interconnecting
leads. The following plugs may be used to connect audio to the console:
Avoid reversing + and - on balanced connections as this will result in reversed polarity (out
of phase) signals which may cause signal cancellation effects.
Where long cables runs are required, balanced interconnections should be used. However,
line level interconnections between more affordable 2-wire (signal, ground) unbalanced
equipment and the console are unlikely to cause problems if the cables are kept shorter
than 10 metres or so. Refer to the wiring diagrams on the opposite page.
Dealing with Ground Loops, Buzz and Interference
For optimum performance all audio signals should be referenced to a solid, noise-free
ground (earth) point, frequently referred to as the ‘star point’ or ‘clean earth’.
A ground loop is created when potential differences exist between grounds at different
points in the system, and the signal has more than one path to ground. In most cases
ground loops do not result in audible problems. Should you experience hum or buzz
caused by a ground loop, check first that each piece of equipment has its own separate
path to ground. If so, operate ground lift switches on connected equipment in accordance
with the instruction manuals. Alternatively disconnect the cable screen at the destination
end only. This breaks the offending loop while keeping the signal shielding down the
length of cable.
WARNING For operator safety, do not remove the ground (earth) connection
in the power lead of the console power supply unit or connected equipment.
To avoid interference pickup keep audio cables away from mains power units and cables,
lighting cables, thyristor dimmer units, computer equipment and mobile phones. Where
this cannot be avoided, cross the cables at right angles to minimise interference
A note about balanced connections
A differentially balanced connection has two signal wires, signal + (hot) and signal - (cold)
and a shield. The signal source generates positive going polarity down the + wire and
negative polarity down the – wire. The destination input stage accepts the + signal on its
non-inverting (+) input pin, but it inverts the – signal, adding it to the + signal. The result is
that the wanted signal is boosted. Now examine what happens when unwanted
interference (hum and noise) is induced into the cable. The noise is induced equally and
with the same polarity into both wires. At the destination input the – wire signal gets
inverted and added to the + signal. Because the polarity is the same on both input wires
the noise cancels itself out at this input. For this interference rejection to work it is important
that the source, the cable and the destination input are all balanced. Balancing provides
greatest advantage with low level signals such as those produced by microphones.
An impedance balanced output provides similar interference rejection, but not as much
maximum drive capability as the differentially balanced output, typically +20dBu versus
+26dBu. It does not generate a negative polarity signal at its – output. Instead, the – wire
has no signal but is held at the same impedance as the + wire. This means that both wires
pick up the noise equally resulting in the advantage of noise cancellation as described
above when connected to a balanced input stage.
GL2800 User Guide
13
The Console Connectors
MONO CHANNEL MIC / LINE IN The LINE (PAD) switch selects
either the MIC XLR or the LINE TRS jack as the input source. The XLR is
normalled through the TRS jack so that it can be used for microphone or
line level signals when nothing is plugged into the jack socket. This gives
the channel preamp a massive headroom with +34dBu maximum input
capability using XLR or jack. Both inputs are balanced but can be wired
to work with unbalanced signals when
INPUT
required. The MIC XLR can be switched to
+IN
1
2
MIC
provide +48V DC via 6k8 ohm resistors to
- IN
pins 2 and 3 for microphones such as
3
condensers which require phantom powering.
TIP +IN
DIRECT
OUT
INSERT
LINE IN
USO RESTRITO
MIC IN
RING -IN
LINE
WARNING: Do not connect unbalanced sources or cables to
the XLR input when 48V phantom power is selected. To avoid loud
clicks always turn the channel off by pressing MUTE when switching
+48V on or off, and when plugging or unplugging cables.
STEREO CHANNEL MIC IN
Each stereo channel features a
mono microphone XLR input and an independent stereo line input. The
balanced MIC input accepts a maximum +14dBu and can be switched to
provide 48V phantom power.
MIC OUT
(BREAKPOINT)
STEREO LINE IN
L/M
STEREO CHANNEL MIC OUT The output of the mic preamp is
available on the MIC OUT (BREAKPOINT) TRS jack socket. This is
impedance balanced and operates at a nominal 0dBu line level.
Plugging into this socket breaks the signal into the associated stereo
channel. This means that the mic preamp can be used independently of
the channel, for example to create an ambience mic feed for recording, or
as a preamp for an RTA measurement system.
R
MIC IN
STEREO CHANNEL LINE IN These inputs are balanced on TRS
jacks. The L input is normalled through the R socket to accept mono
signals on a single jack.
TIP
INSERT
RING
SEND
RETURN
PROCESSOR
RETURN
OUT
SEND
GROUND
RETURN
SEND
INSERT A single 3-pole TRS jack carries the unbalanced insert signal
for each mono channel and main mix output. Tip = send, Ring = return,
Sleeve = common ground. The channel inserts are post-HPF, pre-EQ
and operate at 0dBu. The group (aux) and LRM mix inserts are pre-fader
and operate at -2dBu. Use these to patch in line level signal processing
equipment such as compressors, outboard EQ, delay units and so on.
The wiring of a suitable cable is shown in the diagram.
IN
LINK RING TO SLEEVE TO UNBALANCE
DIRECT OUTPUT Each mono channel direct output is available on
an impedance balanced TRS jack providing a line level signal operating at
0dBu. The source is set using an internal option jumper for each channel.
The factory default setting is pre-fade (following the pre/post-EQ setting).
This may be changed to post-fade if preferred.
TB/GEN
OUT
TB/GEN OUTPUT
LAMP
Use this to provide an external talkback feed, or
to access the console 1kHz oscillator / pink noise generator. You can
patch this into other inputs or equipment as a test signal.
LAMP The console has two 4pin XLR sockets to plug in standard 12V
gooseneck lamps to illuminate the operating surface when working in a
dark environment. Only use lamps intended for this purpose. We
recommend the Allen & Heath LEDlamp with cool white LED illumination
and a built in dimmer.
14
GL2800 User Guide
OUT
Operating Modes
M (WEDGE)
AUX (R)
10
TB/GEN
OUT
AUX (L)
9
AUX (GRP)
8
AUX (GRP)
7
AUX (GRP)
6
AUX (GRP)
5
AUX (GRP)
4
AUX (GRP)
3
AUX (GRP)
2
AUX (GRP)
1
(GRP/AUX REVERSE)
In FOH mode, LR and M feed
the main PA. Groups outputs 18 may be used for multitrack
recording, zone feeds and so
on, or simply left unconnected
where they are used as
‘subgroups’ to LRM for level
masters
and/or
inserted
processing.
USO RESTRITO
In monitor mode Groups 1-8
and LR XLRs and inserts
become the 10 aux mix
masters. Stereo Aux 9-10 is
available on the LR XLRs. M
becomes the engineer’s listen
wedge AFL/PFL feed.
This
configures the console with 10
main stage monitors and an
engineer’s output. The groups
and LRM mix are still available
via the matrix to provide yet
more monitor feeds from the 4
matrix outputs.
OUT
R (10)
OUT
L (9)
GRP (AUX) 8
GRP (AUX) 7
GRP (AUX) 6
GRP (AUX) 5
GRP (AUX) 4
GRP (AUX) 3
GRP (AUX) 2
GRP (AUX) 1
GROUP, L, R, M OUT The main console mix outputs are on
electronically balanced XLR. These produce the professional standard
+4dBu when the meters read ‘0’, and provide up to a maximum +26dBu.
The L, R and M outputs typically feed the house PA system in live sound
mixing, or 2-track and mono recorders in studio mixing. In monitor mode,
these outputs reverse with the Aux TRS jack connections.
AUX OUT 1-10
Each aux send is available on an impedance
balanced TRS jack operating at -2dBu line level. An internal option is
available to fit a balanced line driver IC to provide an electronically
balanced output operating at +4dBu. Note that it is not usual to require
this option as the impedance balanced standard drive provides sufficient
interference rejection when feeding balanced equipment inputs. The aux
sends are typically used to feed monitors, effects devices such as reverb
and delay, and for special mix requirements. In monitor mode, these
outputs reverse with the group and LR XLR connections.
MATRIX OUT 1-4 Each matrix output is available on an impedance
MATRIX EXT IN
MTX
IN
4
MTX OUT
4
MTX
IN
3
MTX
IN
2
MTX OUT
3
MTX
IN
1
MTX OUT
2
(COMMON)
MTX OUT
1
MATRIX EXT IN
IN1
IN2
IN3
IN4
L
OUT
2TRK
L/M
R
R
R
MONITOR
OUT
balanced TRS jack operating at -2dBu line level. An internal option is
available to fit a balanced line driver IC to provide an electronically
balanced output operating at +4dBu. The matrix outputs are typically
used for stereo or mono recording or broadcast feeds, delay and fill
speakers, zone feeds, additional monitors such as IEM, hearing assist
loops and so on.
MATRIX EXT IN 1-4 Each matrix has an unbalanced 0dBu line level
TRS jack input. An external signal such as ambience mix, additional or
sub mixer, remote source, reference tone and so on may be mixed in to
each matrix. The inputs are normalled as shown in the diagram here.
This means that you can plug in just one jack (EXT1) as a common
source to all matrix, two jacks (EXT1,2) as a common stereo source to
matrix pairs, or four independent sources. This is ideal for adding mono
or stereo ambience to recordings or in-ear monitors fed from the matrix.
2-TRACK IN and OUT
Unbalanced TRS jack outputs and TRS
inputs connect to popular recording and playback devices such as CD,
MiniDisc, computers and tape machines. Nominal line level is -2dBu.
The 2-track SEND always follows the post-fade LR mix regardless of
mode switch configuration. The 2-track RETURN can be used for
monitoring a mono or stereo recording, or as a simple input for playback
of walk-in and background music. The L input normals through the R
socket for plugging in a mono source on a single jack.
IN
L
MONITOR OUT
These impedance balanced line level TRS jack
outputs follow the post-level monitor signal. Separate sockets are
provided for the L and R signals. Use these to feed local speaker or other
monitor systems.
SYS-LINK V2 OPTION
Blank plates are fitted here as standard.
The GL2800 Sys-Link V2 (version 2) input/output option kit is available
from Allen & Heath. Refer to OPTIONS later in this guide.
GL2800 User Guide
15
The MONO Input Channel
+48V
POLARITY
LINE
(PAD)
0
20
30
40
GAIN
50
-14
60 40
6
HPF
100Hz
HF
12k
-15
1k
3k +15
4k
700
USO RESTRITO
HM
-15
15k
180
+15
250
45
400
35Hz
1k
-15
+15
-15
+15
LF
WARNING: Do not connect unbalanced sources or cables to
inputs with phantom power selected. To avoid loud clicks always
mute the channel before switching +48V on or off and when
plugging or unplugging microphones.
6k
500Hz
70
LM
+48V Switches +48VDC to the channel input XLR for powering
microphones or DI boxes that need phantom power. The power is
current limited through 6k8 ohm resistors to pins 2 and 3.
80Hz
EQ IN
AUX
1
+6
OO
AUX
2
PRE-EQ
POLARITY Reverses the polarity (+ and – connections) of the
input source. Useful when using the ‘above/below’ mic technique, for
example when miking a snare drum with two microphones, or for
correcting mic placement and cable wiring errors.
LINE (PAD) Press this switch to select the channel TRS jack LINE
input. Release the switch to select the XLR MIC input. The XLR
normals through the TRS socket. With nothing plugged into the line
input the switch therefore becomes a PAD for the mic XLR. It
attenuates the input signal by 20dB for connection to high level
microphone or line sources. This gives the mic preamp a 74dB range
and headroom of +34dB to deal with the hottest signals.
AUX
3
OO
+6
OO
+6
AUX
4
POST
PRE
AUX
5
OO
+6
OO
+6
OO
+6
OO
+6
GAIN Adjusts the input sensitivity to match the connected source to
the internal 0dBu operating level of the channel. Provides a variable
54dB range from +6 to +60dB gain (mic), or -14 to +40dB (line,
padded mic). The gain should be set so that the channel meters
average ‘0’ with loudest moments lighting ‘+6’. Reduce gain if the red
peak indicator lights.
AUX
6
AUX
7
AUX
8
POST
PRE
Important note on setting channel levels: Use PFL to set the GAIN
controls for correct signal level through each channel. The main LR
meters provide a high resolution display of the channel signal level.
Use the faders to balance each signal in the mix. To ensure optimum
gain structure we do not recommend the practice of setting the faders
to ‘0’ and mixing using the GAIN controls.
AUX
9-10
STEREO
OO
+6
=
PAN
L
R
POST
PRE
HPF Switches in the channel high pass filter. This attenuates
frequencies below 100Hz by 12dB per octave. The filter is pre-insert,
pre-EQ. Select the HPF to reduce low frequency noise such as
microphone popping, stage noise and tape transport rumble.
=
PAN
R
EVEN
L
ODD
MUTE
PFL
PK!
+6
0
SIG
M
10
5
L-R
0
1-2
5
3-4
5-6
10
7-8
20
M1
30
M2
M3
M4
16
00
EQ A responsive 4-band semi parametric EQ (equaliser) provides
independent control of four frequency bands. Use EQ IN to compare
the sound with the equaliser switched in or out of circuit.
HF and LF are shelving filters which affect high frequencies above
12kHz, and low frequencies below 80Hz respectively. HM and LM are
bell shaped peak/dip filters which affect frequencies around a centre
point which can be swept from 500Hz to 15kHz, and 35Hz to 1kHz
respectively. These have a width (Q) of 1.8 which provides effective
control for both creative and corrective equalisation. The EQ curves
shown opposite display the signal level response at maximum boost
and cut as the frequency varies from low (20Hz) to high (20kHz).
All bands can be boosted or cut by up to 15dB and have a centre
detent 0dB position. The overlapping frequency ranges let you deal
with challenging source problems easily using combinations of bands.
Check that you are using the best microphone type and placement
before using the EQ. Start with the EQ set flat and apply only as much
boost or cut as is really needed. When dealing with problem
frequencies cut rather than boost where possible.
GL2800 User Guide
AUX SENDS
These rotary controls adjust how much channel
signal is mixed to each of the aux outputs. They adjusts from fully off
to +6dB boost. Unity gain 0dB is marked at 3 o’clock position.
HPF
+5
0dB
-5
AUX SENDS 1-8 Mono aux sends with independent control.
-10
-15
AUX SENDS 9-10
A dedicated stereo aux send with level and
pan controls. Set pre-fade to create stereo monitor mixes such as IEM.
Set post-fade to create stereo recording feeds or to balance between
two effects devices such as reverb.
-20
-25
-30
-35
-40
USO RESTRITO
10
20
50
100
200
500
1k
2k
5k
10k
fader. Auxes 1 to 4, 5 to 8 and stereo aux 9-10 are grouped for
pre/post switching. Pre-fade aux sends are not affected by the channel
fader movements. These are typically used to feed stage monitors.
Post-fade aux sends follow the channel faders and are typically used
to send a proportion of the channel signal to an effects device such as
reverb or delay. Note that post-fade sends may be preferred when the
console is configured in monitor mode so that the faders become
channel ‘masters’ affecting all monitor mixes.
LF / HF
+20
+15
+10
+5
0dB
-5
-10
PRE-EQ Changes the pre-fade aux source from post-EQ (switch up)
to pre-insert, pre-EQ (switch pressed) so that inserted compressors
and the EQ do not affect the sends when mixing monitors from FOH.
This affects all auxes set pre-fader for the channel. The switch is
recessed to prevent accidental operation once set. Use a pointed
object to change the setting.
-15
-20
20
50
100 200
500
1k
2k
5k
10k
HM
+20
+15
PAN
Positions the channel signal between L/R in the stereo mix,
and odd/even if routed to the groups. The centre position (mono
image) is detented for quick resetting.
+10
+5
0dB
MUTE When pressed, the channel signal is turned off. This affects
-5
-10
-15
-20
20
50
100 200
500
1k
2k
5k
10k
20k
LM
the feed to the LRM mix, pre and post-fade aux sends and direct
output, but does not affect the insert send. The red indicator lights
when the channel is muted. Always mute the channel when switching
phantom power or plugging the cables and sources.
PFL Press PFL to listen to the pre-fade channel signal in the
headphones and local monitor without affecting the main outputs.
The console PFL/AFL active red indicator lights and the monitor LR
meters display the channel signal. Selecting more than one PFL at
the same time mixes those signals together in the monitor.
+20
+15
+10
+5
0dB
METER A 4 LED channel meter displays the pre-fader signal level.
-5
-10
+20
+16
+12
+9
+6
+3
+1
0
-1
-3
-6
-9
-12
-16
-20
-30
-40
-50
-60
-70
200
500
1k
2k
5k
10k
CLIPPING
SIGNAL
DYNAMIC RANGE
100
HEADROOM
50
SIGNAL-TO-NOISE RATIO
20
NORMAL OPERATING RANGE
-15
-20
PRE Press to select the channel pre-fader source, release for post-
ROUTING Press to route to the required combination of L-R, M
and the 8 groups. Use PAN to position the signal between L/R or the
odd/even group pairs. To route to a single group set PAN fully to one
side. Check that you have set these switches correctly before you start
mixing.
FADER A 100mm smooth travel fader with protective dust cover
controls the channel level feeding the main mix, groups and post-fade
aux sends. It also affects the direct output if this has been set to postfade using the internal option jumpers. The fader provides +10dB
maximum boost above its normal unity gain 0dB position.
-80
-90
!
20k
‘SIG’ lights when a signal level of -12dBu is detected. ‘0’ lights when
the nominal 0dBu level is reached, and ‘+6’ at +6dBu. ‘PK’ lights
when the channel pre-fade signal is within 5dB of clipping. This gives
you enough warning to reduce GAIN before you hear signal distortion.
NOISE
GL2800 User Guide
MUTE GROUPS
Press these switches to add the channel to
Mute Groups 1 to 4 as required. Pressing the master mute switch
mutes all channels assigned to that group.
17
The STEREO Input Channel
+48V
POLARITY
LINE
(PAD)
0
20
30
40
GAIN
50
-14
6
60 40
HPF
100Hz
STEREO
GAIN-10
-5
0
-20
5
-30
OO
16
-15
+15
-15
+15
Each GL2800 stereo channel features a mono microphone preamp
as well as a stereo line input. These sources can be mixed together
into the channel or split using the mic breakpoint, so providing a
unique flexibility. For example, you could patch the mic stage as an
independent preamp for an ambience microphone feeding a
recording, or for a system calibration microphone, while the stereo line
input returns an external effects processor to the mix. Two stereo
channels could be linked so that the mic preamps cross patch to
provide one stereo mic and one stereo line channel.
HF
USO RESTRITO
12k
HM
2k5
LM
250Hz
-15
+15
MIC INPUT Similar to the mono channel microphone preamplifier.
A rear panel MIC OUT breakpoint socket is provided so that the mic
stage can be used independently. Plugging a jack into the MIC OUT
socket breaks its signal path to the stereo channel.
LF
80Hz
-15
+15
EQ IN
AUX
1
OO
+6
OO
+6
OO
+6
OO
+6
AUX
WARNING: Do not connect unbalanced sources or cables to
inputs with phantom power selected. To avoid loud clicks always
mute the channel before switching +48V on or off and when
plugging or unplugging microphones.
2
AUX
3
AUX
4
POST
PRE
AUX
STEREO LINE INPUT A level control adjusts from fully off to
+16dB gain. The L input signal is normalled through the R input
socket so that a mono source may be plugged in to feed both left and
right sides of the stereo channel.
5
OO
+6
OO
+6
OO
+6
OO
+6
AUX
AUX
7
AUX
8
POST
PRE
AUX
9-10
STEREO
OO
+6
=
BAL
L
L
ODD
R
EVEN
MUTE
PFL
PFL Press PFL to display the summed L+R pre-fade channel signal
on the monitor meters and listen to it in the headphones and local
monitor without affecting the main outputs.
METER
As the mono channel, but the left and right signals are
summed to display in mono.
5
ROUTING As the mono channel, but routes the left signal to L and
0
1-2
5
3-4
10
7-8
20
M1
MUTE When pressed, all the channel pre and post-fade signals are
10
L-R
5-6
BAL Balances the level of the L signal against the R signal to
compensate for differences in the source, or to position the signal
within the stereo image.
turned off except the MIC OUT and any stereo routed direct to LR.
=
BAL
M
AUX SENDS These work as described for the mono channel, but
the L and R sides of the stereo signal sum together to feed Auxes 1 to
8 in mono. Aux 9-10 is fed with the stereo signal. The auxes can be
switched pre or post-fader but are always sourced post-EQ.
R
POST
PRE
PK!
+6
0
SIG
EQ Similar to the mono channel, but the two peak/dip mid bands
are fixed at 250Hz and 2.5kHz centre frequencies.
6
odd groups, right signal to R and even groups, and sums L and R to
feed the M mix in mono.
FADER The stereo fader provides +10dB maximum boost above
its normal unity gain 0dB position
MUTE GROUPS Assign the stereo channel to any combination of
the 4 mute groups by pressing these switches.
30
M2
M3
00
M4
18
GL2800 User Guide
USO RESTRITO
The STEREO Return Channel
Two additional dual stereo return channels are provided. Each has
two stereo line inputs which can be mixed together or used
separately. ST1 and ST3 can be routed directly to LR instead of the
return channels. This gives you the flexibility of mixing in four more
stereo sources in a small panel space.
ST1 INPUT
DUAL STEREO RETURN
STEREO
GAIN -5
0
5
-10
ST3
10
-20
16
OO
DIRECT TO
STEREO
GAIN -5
0
5
-10
LR
ST4
10
-20
OO
16
OO
+6
OO
+6
AUX
1
AUX
2
AUX
9-10
+6
OO
MUTE
PFL
10
M
5
L-R
0
3-4
5
10
20
30
OO
A level control adjusts from fully off to +16dB gain.
The L input signal is normalled through the R input socket so that a
mono source may be plugged in to feed both left and right sides of the
stereo channel. A recessed switch can be set to route the source
directly to the L-R mix instead of the return channel. Use a pointed
object to change the switch setting.
ST2 INPUT
A level control adjusts from fully off to +16dB gain.
The L input signal is normalled through the R input socket so that a
mono source may be plugged in to feed both left and right sides of the
stereo channel.
AUX SENDS Use these controls to feed the return signal to a
combination of the auxes. The stereo signal is summed to feed Aux 1
and Aux 2 in mono. The signal feeds aux 9-10 in stereo. Internal
jumper options are provided to set the auxes pre or post-fader. Default
setting is post-fade so that the fader provides master control for all the
sends.
MUTE When pressed, all the channel pre and post-fade signals are
turned off except ST1 or ST3 if routed direct to LR.
PFL Press PFL to display the summed L+R pre-fade channel signal
on the monitor meters and listen to it in the headphones and local
monitor without affecting the main outputs.
ROUTING Routes the left signal to L and odd group 1 or 3, and the
right signal to R and even group 2 or 4, and sums L and R to feed the
M mix in mono. Return channel ST1-2 can be routed to Groups 1-2,
and ST3-4 can be routed to Groups 3-4.
FADER
A 60mm stereo fader provides +10dB maximum boost
above its normal unity gain 0dB position.
Applications for the stereo channels and returns are described later in
this user guide.
GL2800 User Guide
19
The GROUP / AUX Masters
AUX 1-8 MASTERS Each aux mix has a master level control that
AUX
0
1
OO
+10
AFL
USO RESTRITO
REV
GRP1
TO M
GRP1
TO LR
=
PAN
L
R
PK!
+6
0
SIG
MUTE
AFL
GRP1
AUX1
adjusts the output level to match external equipment, or trims the
monitor, effect or other send without affecting the mix balance. Up to
+10dB boost is available above the normal 0dB position. Note that
this becomes the group master in monitor mode.
AUX AFL
Press AFL to listen to the post-level aux mix in the
headphones and local monitor without affecting the main outputs.
The console monitor meters are interrupted with the aux (group)
signal. The yellow indicator lights to show that AFL has been selected
on the master. Use AFL to check the signal being sent to the
monitors, effects or other destination. AFL is pre-mute so that you can
check the signal before sending it to its destination.
REV mode switch These switches reverse the function of the
group and aux masters, the heart of the dual functionality pioneered
by Allen & Heath. They are recessed to prevent accidental operation.
Use a pen or pointed object to set their position. In the up position
(flush with the panel), the group is controlled by the fader and the aux
by the rotary master. This is typical for FOH mode where the faders
are used for subgroups feeding the main stereo mix. When pressed,
the aux uses the fader as the master and the group is moved to the
rotary control. The aux mix is now presented to rear Group XLR
complete with insert. The group mix appears at the Aux TRS jack.
This is used for monitor mode where the auxes are the main mix
feeding the stage monitors. You can select any combination for the
FOH and monitor mode, for example, just four giving you 4 fader
subgroups for level control, 4 groups on rotaries for inserting effects,
4 monitor sends on faders, 4 effects sends on rotaries and main mix.
10
Note: The groups always feed the matrix and the subgroup controls
regardless of mode. This means the group mix can still perform a
useful function when the console is configured in monitor mode.
5
GRP to LR/M
Press to route the post-fade group signal to L-R
and/or M. These provide sub grouping to the main mix for grouped
level control and inserted processing.
0
PAN Positions the group signal between L and R in the stereo mix
5
when the GRP TO LR switch is pressed. Using pan you can create
mono or stereo groups positioned as you require in the main mix. For
stereo grouping, set the odd group pan fully to the left, and the even
group pan fully to the right. Note that the group mix always feeds
these subgroup controls regardless of FOH or monitor mode selected.
10
METER
20
A 4 LED bar meter displays the post-fade group signal
(FOH mode), or aux signal (monitor mode, REV pressed).
30
MUTE When pressed the group (aux) signal is turned off. This
affects the feed to the output XLR, LR, M and matrix. The red indicator
lights when the channel is muted. Mute does not affect the AFL
monitoring.
00
GROUP AFL Press AFL to listen to the post-fade, pre-mute group
1
mix in the headphones and local monitor without affecting the main
outputs. Note that this becomes the aux mix in monitor mode. The
console monitor meters are interrupted with the group (aux) signal.
GROUP FADER A 100mm smooth travel fader controls the group
mix output level. Note that it becomes the aux mix master in monitor
mode (REV pressed). The fader provides +10dB maximum boost
above its normal unity gain 0dB position.
20
GL2800 User Guide
USO RESTRITO
The MUTE, AUX 9-10 and L-R-M Masters
MUTE MASTERS 1-4 Press to mute all the input channels
assigned to the mute group. Any combination of masters may be
active at any time. The red LED indicates that the master is active.
AUX 9-10 MASTER Controls the master level of stereo Aux 9-10.
AUX
9-10
AUX
9-10
STEREO
OO
MUTE
MONITOR
+10
MUTE GROUPS
REV
WEDGE
MODE
0dB
PK!
+6
0
SIG
PK!
+6
0
SIG
AUX9-10
M
R
AUX MUTE When pressed the stereo aux (LR) signal is turned off.
The red indicator lights when the channel is muted.
PK!
+6
0
SIG
MUTE
L
REV mode switch Reverses Aux 9-10 rotary master with the L-R
faders, inserts and XLR outputs. Recessed to prevent accidental
operation. Use a pen or pointed object to set the position. In monitor
mode (switch pressed) the stereo aux is controlled by the main faders,
for example to provide a stereo in-ear monitor mix.
Note: LR always feeds the matrix and LR to M controls regardless of
mode. This means the LR mix can still perform a useful function when
the console is configured in monitor mode. The Aux mix is always
monitored by selecting the nearby monitor select AUX 9-10 switch.
L-R TO M
OO
Up to +10dB boost is available above the normal 0dB position. Note
that this becomes the LR master in monitor mode.
LISTEN
LR to M Dials the sum of L and R into the M mix to create a mono
output from the stereo mix. You can use this to create a starting point
for a fill or centre mix, and then add selected channels using their M
routing switches. This control always routes the LR signal to M
regardless of mode.
METERS
4 LED bar meters display the post-fade LRM master
signals (FOH mode), or aux 9-10 and engineer’s wedge signal
(monitor mode, REV pressed)
10
10
10
5
5
5
0
0
0
5
5
5
Separate 100mm faders control the main mix L
and R output levels. They provide +10dB maximum boost. Each
master includes a 4 LED bar meter and a MUTE switch so that L and R
can be separately muted. This is also useful in monitor mode where
these masters carry the Aux 9-10 signals.
10
10
10
M MASTER A 100mm fader adjusts the level of the M mix. The
LR MASTERS
master is fully featured and includes a 4 LED bar meter and a MUTE
switch.
20
20
20
30
30
30
00
00
00
L
R
WEDGE mode switch This switch is recessed to protect it from
accidental operation during the show. Use a pointed object to set its
position.
FOH mode – In the up position (flush with the panel), the fader is the
master for the main M mix, typically used to feed a mono fill or C
(centre) mix.
M
GL2800 User Guide
Monitor mode - Press to create an engineer’s monitor listen wedge
feed from the AFL/PFL mix. It is common to use a wedge speaker of
the same type used on stage to listen to and check the various
monitor mixes being sent to the performers. Together with the
group/aux REV function, the GL2800 can be configured as a
compact yet fully featured monitor console.
21
12x4 MATRIX
EXT
IN
OO
+6
GRP
USO RESTRITO
1
OO
+6
OO
+6
OO
+6
OO
+6
GRP
2
GRP
3
GRP
The matrix adds to the powerful multi-tasking capability of the
GL2800. It provides a set of 4 additional console outputs. It is a
‘mixer within a mixer’ creating its output from any combination of the
groups, main LR mix and external inputs. It can be used to provide
duplicate main outputs or to create new mixes from these outputs.
The matrix controls are positioned conveniently away from the live
performance controls to avoid accidental operation.
Use the matrix to create special mixes for delay fill and zone speakers,
recording and broadcast feeds, IEM (in-ear monitors), hearing assist
loops and so on. Mono and stereo feeds can be created. For
example, mix L and R to create a mono sum output to feed an
additional zone, or use two matrix outputs with L fed to one, R to the
other to create an independent stereo main output. Mix in an external
source such as an ambience microphone preamp to add atmosphere
and audience reaction to a recording or monitor. Compensate for an
acoustically loud backline by boosting selected groups in a live
recording. For more information, refer to ‘Operating Tips’ later in this
guide.
4
GRP
5
OO
+6
OO
+6
GRP
6
EXT IN Mixes in an external nominal 0dBu line level source. The
rotary provides +6dB boost. Note that EXT IN jack sockets are
normalled (linked) in a way that lets you plug in a mono or stereo
common source to feed all the matrices, or an independent source to
each. Plug into EXT1 only to feed one source to all four matrix EXT IN
controls. Plug L into EXT1 and R into EXT2 only to feed a stereo
source to matrix 1-2 and 3-4.
MATRIX EXT IN
GRP
IN1
IN2
IN3
IN4
7
OO
+6
OO
+6
OO
+6
GRP
8
L
R
Some examples include adding ambience sources to recordings and
in-ear monitoring, adding a direct output or an aux mix to quickly
create a monitor from the main mix plus selected channel/s, and
linking in another console to feed the same PA in a festival or other
dual console situation.
GRP 1-8 Mixes in the post-fader, post-mute group mix. The rotary
provides +6dB boost.
OO
+6
OO
+6
M
LEVEL
L,R,M Mixes in the post-fader, post-mute main LR mix. The rotary
provides +6dB boost. Turn up both L and R to create a mono sum
from the stereo LR mix. Turn up L in one matrix, R in another to create
a stereo output from two matrices.
LEVEL
OO
MUTE
+6
The master level control (fader) for the matrix. Provides
+6dB boost above the normal ‘0’ setting.
MUTE
When pressed the matrix output is turned off. The red
indicator lights when the matrix is muted. Mute does not affect the
matrix AFL monitoring.
Note that the matrix mix can be checked using the meters and
headphones by selecting the related monitor select switches. These
provide both mono and stereo monitoring of the matrix.
22
GL2800 User Guide
USO RESTRITO
2-TRACK REPLAY and CONSOLE MONITOR
2TRK REPLAY A stereo source such as a recording playback or
PHONES
walk-in CD can be routed directly to the main LR mix. Adjust its level
from fully off to +10dB gain using the rotary control. You can check
the source on the meters and in the headphones before bringing it
into the mix by selecting the 2TRK monitor switch.
Console Monitor
2TRK REPLAY
TALKBACK
MIN
MAX
+10
OO
2TRK
TO LR
OSC/NOISE
POWER
MIN
MAX
PINK NOISE
1kHz OSC
L
R
+16
+9
+6
+3
0
-3
-6
-9
-12
-16
-20
-30
ON
M
L-R
PFL/AFL
MTX3-4
MONITOR
0
10
AUX
3-4
M
AUX
5-8
L-R
AUX
9-10
2TRK
LATCH
TALK
The console monitor meters provide 12 LED indicators to accurately
display the signal level of the selected monitor source. Reduce the
gain or level if the red ‘+16’ peak indicator lights. For optimum
performance the signals should be adjusted to read an average ‘0’
with loudest peaks reaching around ‘+6’.
Use the MONITOR level control to adjust the level in the headphones
and local speaker monitor. We recommend you use closed ear
headphones in the range 30 to 600 ohms designed for live sound
monitoring. 100 ohm headphones are a popular choice.
MTX1-2
AUX
1-2
Comprehensive engineer’s headphones and
local monitoring is provided. Select the source from the monitor
select switch bank. Pressing PFL or AFL elsewhere on the console
automatically overrides the current monitor source with the signal from
the channel or master selection. The red PFL/AFL active indicator
illuminates and the console meters display the active signal.
Three headphones sockets are provided for convenience. One ¼”
standard TRS is at the front under the armrest, a second at the top
near the talkback mic. A small 3.5mm socket is also provided for
plugging in headphones or earpieces fitted with a mini jack. It is useful
to monitor an in-ear mix using the same type of earpiece as used by
the performers.
WARNING:
To avoid damage to your hearing do not
operate any close-to-ear monitoring such as headphones for long
periods at high volume. Continued exposure to high volume
sound can cause frequency selective or wide range hearing loss.
MTX1
STEREO
MTX2
MTX3
STEREO
MTX4
AUX
9-10
AUX
9-10
Stereo Monitoring The GL2800 has been designed to offer
maximum capability for working with multiple stereo mixes such as
IEM and recording feeds. It is important to be able to hear exactly
what you are sending from the console. Press AUX 9-10 to check the
stereo aux mix. Press one switch to check a matrix in mono, two to
check a related pair in stereo. For example, press MTX1 to listen to a
mono fill mix, or press MTX1 and MTX2 together to listen to a stereo
recording mix.
STEREO
OO
+10
MONITOR
Monitor Selection With all select switches in the up position, no
source is monitored unless PFL or AFL is activated. Press a switch to
select the required monitor source. Press two together to select stereo
as described above. Switches nearer the faders take priority. For
example, press L-R to listen to the main mix. Then press 2TRK to
override the L-R source until it is released.
GL2800 User Guide
23
USO RESTRITO
TALKBACK and SIGNAL GENERATOR
TALKBACK Individually assignable talkback is available to all the
PHONES
2TRK REPLAY
TALKBACK
MIN
MAX
2TRK
TO LR
POWER
MAX
PINK NOISE
1kHz OSC
L
R
+16
+9
+6
+3
0
-3
-6
-9
-12
-16
-20
-30
ON
M
L-R
MTX1-2
PFL/AFL
MTX3-4
MONITOR
AUX
1-2
0
10
AUX
3-4
M
AUX
5-8
L-R
AUX
9-10
2TRK
LATCH
TALK
MTX1
STEREO
MTX2
MTX3
STEREO
MTX4
AUX
9-10
AUX
9-10
STEREO
OO
24
+10
WARNING: Do not connect unbalanced sources or cables to
inputs with phantom power selected. To avoid loud clicks do not
press the TALK switch when plugging or unplugging the talkback
microphone.
+10
OO
OSC/NOISE
MIN
main outputs. Plug in a suitable cable or gooseneck microphone. A
good quality dynamic or condenser vocal microphone is
recommended. Note that +48V phantom power is available at the
XLR as standard. If you prefer, this can be disabled by repositioning
an internal jumper link.
MONITOR
TALKBACK enable First select the source you wish to talk to.
You can select the auxes in logical groups, useful for communicating
with the performers on stage. The matrix can be enabled in pairs,
ideal for working with stereo in-ear monitors or communicating with an
outside broadcast facility. You can also talk to LR and M, typically
used for announcements to the audience. Once selected, press and
hold TALK to route the mic to the required destination. Adjust the
talkback level using the TRIM control below the TB mic XLR. Pressing
TALK automatically dims the level of the signal generator if it is turned
on.
TALK latch mode Press this switch to permanently activate the
TALK switch. This is useful when using a handheld microphone with
built-in switch for talkback. It means you do not need to press the
TALK switch to talk to your enabled destinations. Simply use the
switch on the microphone. The latch switch is recessed to prevent
accidental operation. Use a pointed object to change its setting.
SIGNAL GENERATOR / PINK NOISE Press to select either
pink noise (up position) or a 1kHz sine wave tone as the test source.
Start with the trim control turned fully down. The generator ON switch
is recessed to prevent accidental operation. Press this with a pen or
pointed object. The green indicator lights to warn that the generator is
enabled.
The generator signal is routed to any source selected on the switch
bank above the TALK switch. Use the signal to test the loudspeaker
system and line up connected equipment. Pink noise is useful for
quickly testing the full range frequency operation and phasing/polarity
of loudspeakers. The 1kHz tone is better suited to lining up
equipment with its steady reading on the meters.
WARNING: We recommend you turn off the signal generator
once you have finished using it to test and line up your system.
This will prevent accidental operation during the show.
GL2800 User Guide
The following is a collection of brief descriptions, application notes,
hints and tips to help the operator understand some of the technical
terms referred to, and to get the most out of the uniquely capable
GL2800 live sound mixing console. They are written as a concise
reference to spark your imagination to creatively and effectively deal
with the many challenges now faced in modern day mixing.
Gain Structure
-40
-50
-60
-70
SIGNAL
DYNAMIC RANGE
-30
CLIPPING
HEADROOM
+20
+16
+12
+9
+6
+3
+1
0
-1
-3
-6
-9
-12
-16
-20
SIGNAL-TO-NOISE RATIO
NORMAL OPERATING RANGE
USO RESTRITO
GL2800 Applications and Operating Tips
-80
-90
NOISE
☺
A search on the Internet
can reveal a host of additional
information on setting correct
gain structure and many other
audio topics and educational
resources.
!
The term used to describe the gain (level)
matching of the signal through the audio system chain. Each item in
the equipment chain has its own optimum (‘nominal’) operating level
determined by its electrical circuits. If you overload it with a signal that
is too high then its output tries to produce more voltage than its power
rails can provide resulting in harsh sounding distortion as the audio
signal is ‘clipped’. If you work with a signal that is too low then you
are likely to hear the residual hiss of the circuits as the ‘noise floor’ is
amplified along with the signal. The optimum operating level is the
point at which the signal is high enough above the noise floor so that
the hiss is not heard (good ‘signal-to-noise’ ratio, the SNR), yet
provides enough space (‘headroom’) before clipping to allow for the
louder, dynamic musical moments without distortion. ‘Dynamic range’
specifies the maximum range between noise floor and clipping. It is
the sum of the SNR and headroom. The larger the figure the better…
less noise, more headroom, more forgiving to wide ranging signals.
A microphone produces a very tiny signal, for example -50dBu (a few
millivolts). This should be amplified by the channel preamp to the
optimum operating level of the console circuits, around 0dBu
(0.775V), well clear of the noise floor (typically less than -90dBu), and
with good headroom (typically clipping at greater than +20dBu). With
a channel routed at unity gain from preamp input to main output, the
GL2800 boasts a massive 116dB dynamic range. The signal can
pass through many stages which affect its level within the console; the
channel, its EQ, fader, pan, a group mix and its fader, on to the main
LR mix with its master fader, through the matrix, and of course any
inserted equipment. The output XLR provides the professional
standard +4dBu (1.23V) nominal level to the next stage in the audio
chain, typically a speaker processor such as limiter or crossover, or
straight to the amplifier. The amp boosts this signal to tens of volts to
move the speaker cones so producing the audible sound.
To get the best performance from your system, it is important that you
set up the gain structure correctly within the console and also within
and between the connected equipment. Ideally, each circuit should
be set to clip at the same time if the signal became too hot, in other
words each would have similar headroom relative to its nominal
operating level. The resulting dynamic range is the difference
between the highest noise floor and the lowest headroom through the
system. The performance is only as good as the weakest link.
The GL2800 provides comprehensive metering to check every
point within the console signal path. Use the channel meters and
PFL/AFL system to set the gains and mix levels to average around ‘0’
meter reading with usual peaks around ‘+6’. Reduce the gain if the
red ‘+16’ or ‘PK’ indicator lights.
Use the equipment meters to set each item within the system path to
operate at its nominal level. We advise that the speaker processor or
amplifier trims are set so that the console outputs can drive up to their
nominal ‘0’ level. It is a common mistake to set amplifier trims to
maximum sensitivity when this results in the console master faders
being operated at very low positions, with low meter readings, and
reduced dynamic range and therefore audible residual system hiss.
GL2800 User Guide
25
Using the Oscillator / Noise Generator The GL2800
includes a useful signal generator able to produce a pure 1kHz sine
wave tone, or a pink noise test source. This is invaluable in testing the
system components and setting up correct gain structure. The
generator can be routed independently to the various console outputs.
OSC/NOISE
MIN
MAX
PINK NOISE
1kHz OSC
ON
USO RESTRITO
M
L-R
MTX1-2
MTX3-4
AUX
1-2
AUX
3-4
AUX
5-8
AUX
9-10
LATCH
TALK
0
20
GAIN
-14
26
30
40
50
6
60 40
Use the 1kHz tone to line up the connected equipment. For example,
a recorder, video camera or broadcast feed from the matrix. Route the
tone to the matrix. Set the matrix LEVEL control to its 3 o’clock ‘0’
position. Press the matrix AFL and adjust the oscillator level until the
console monitor meters read ‘0’. Next, adjust the recorder input trim
so that its meters also read ‘0’. The recorder is now correctly aligned
to the operating level of the console. Similarly, you could match the
console LR output to a DSP speaker processor by sending the tone to
LR, setting the faders for output meters reading ‘0’, and then trimming
the processor input for ‘0’ on its meters. To prevent a loud tone
through the speakers it is best to do this with the amplifiers turned off.
Use the Pink Noise generator to check the signal routing and
loudspeaker response. ‘Pink noise’ is a random signal that contains
all audio frequencies and is therefore a very good test source. Unlike
‘white noise’ which has equal energy per Hz and sounds like system
or inter-band tuner hiss, pink noise has equal energy per octave, a
response that matches the logarithmic way our ears perceive sound.
You can hear all the frequencies clearly from deep bass, through mid
to treble. This means you can route the noise to a speaker system
and quickly hear if one of the sub, mid or HF drivers is faulty. With the
noise sent to several speakers at the same time you can listen for
comb filtering effects, and the severe phasing effect which indicates
that one of the speakers may have its wires reversed. Pink noise is
also used with an RTA (real time analyser) when measuring room
frequency response. Testing a system with pink noise through the
speakers is often referred to as ‘pinking the room’.
The GL2800 signal generator is an invaluable tool for calibrating
and testing the system during setup. To prevent any unexpected
mishaps during the sound check or show, remember to disable it by
releasing the recessed ON switch once you have finished the testing.
We also advise that you always start the calibration with the
OSC/NOISE trim turned fully off so that you can bring it up gradually
without the risk of overloading the destination.
Mixing with faders or gain controls? There is a technique
used by some operators where they set all the faders to ‘0’ position
and balance the mix using the channel gain controls. We do not
advise this method as the signal to noise ratio and control resolution
can be severely degraded. In addition, it is impossible to mix monitors
from FOH in this way as changes to the gain settings affect the
monitors too.
The correct method is to use GAIN to match the source to the
operating level of the channel for optimum dynamic range, and then
use the FADERS to balance each source into the mix. With correct
system gain structure, prime sources such as vocals would have their
faders operated around ‘0’ while sources low in the mix such as
backing vocals and acoustically loud brass and drums would display
their true contribution with their lower fader positions. This is a much
more visual and accurate way of mixing.
GL2800 User Guide
USO RESTRITO
AFL
Note: The stereo Aux 9-10
and matrix 1-4 outputs can
be monitored using the
monitor select switch bank.
This provides true stereo
monitoring of these mixes.
PFL/AFL automatically
overrides any source
selected on this
switchbank.
dB
Tech talk…
For an audio circuit stage:
Pi = Input signal power
Po = Output signal power
The Decibel is defined as:
dB = 10 log (Po / Pi)
= 10 log (Vo2/Ro / Vi2/Ri)
If input and output impedances
Ri and R0 are the same, then:
dB = 20 log (Vo / Vi)
dBm is defined as 1mW into
600 ohms = 0.775V
dBu = 0.775V ignoring the
600 ohms as we assume high
input and low output
impedance and therefore
maximum voltage transfer
between stages, appropriate
for modern audio.
☺
If you suspect the insert
socket to be faulty or
intermittent through excessive
wear or contamination, test for
this by plugging in a jack with
its tip shorted to its ring
contact. This bypasses the
contact in the socket. Clean
using
suitable
electrical
contact cleaner.
GL2800 User Guide
Using PFL / AFL Allen & Heath are renowned for bringing you
the most comprehensive engineer’s monitoring system in consoles at
this price point. We recognise the importance of correct gain structure
and signal handling. The GL2800 includes LED meters for every
input channel and main output, as well as a pair of high resolution
meters dedicated to monitor duty only. In monitor mode the M fader
and associated controls become a full featured PFL/AFL monitor feed
for the engineer’s listen wedge.
The input channels provide PFL (pre-fade listen) so that each source
can be checked using the meters and headphones before you bring
the fader up. You can even use PFL while the channel is muted to
prevent the signal reaching the house and monitor speakers until you
have checked it and are ready.
All the main and aux outputs provide AFL (after-fade listen) so that you
can check the exact level leaving the console. Once again, the AFL
switch gets its source before the output mute switch so that you can
check the signal before you send it to its destination. This can be very
important when you are feeding remote destinations such as
broadcast and recording.
The Decibel the ‘Bell’ is the unit of sound level. Decibel is 1/10
Bell, a more conveniently sized unit. dB = 20 log (Vo / Vi) where Vi
and Vo are two signal voltages, in and out (ignoring the impedances).
The dB is used to express the relationship between two levels, chosen
because of the logarithmic way our ears respond to sound. The ‘dB’
relates one level to another. For example, a preamp with a gain of
40dB (100x) would produce an output of +10dBu for an input of 30dBu. Several audio standards exist to relate a signal level to a
known reference. Audio engineers need to deal with a variety of
equipment standards, for example, a -10dBV CD player plugged into a
console with +4dBu outputs connected to a 0dBu input DSP speaker
manager, or an operator using an SPL (sound pressure level) meter to
measure sound intensity.
dBu
Relative to 0.775Vrms – professional standard
0dBu = 0.775V
+4dBu = 1.228V
dBV
Relative to 1Vrms - consumer audio standard
dB-A
Sound pressure with a filter contour to approximate
the response of the human ear. Three curves A, B,
C exist for different loudness.
dBfs
Relative to signal maximum before clip (full scale)
0dBV = 1V
-10dBV = 316mV = -8dBu
Using Inserts The GL2800 channel inserts operate at 0dBu,
the output inserts operate at -2dBu. In practice this makes little
difference as long as the inserted equipment is intended for line level
operation (-6 to +4dBu). Simply set the gain through the device to
unity (0dB) with the bypass switch pressed (if available). With the
effect switched in, use the console channel gain control to make any
further adjustments needed. This keeps the gain structure correct
through the channel signal path.
INSERT
SEND
TIP
RING
RETURN
With nothing plugged into the insert, the channel signal is routed
through a switching (‘normalling’) contact in the socket. As soon as a
jack is plugged into the socket the contact is opened and the signal
path broken so that the external device can be patched in series with
the signal.
27
Polarity
USO RESTRITO
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.
GL2800
DUAL STEREO RETURN
STEREO
GAIN -5
0
DUAL STEREO RETURN
STEREO
ST1
5
GAIN -5
-10
0
STEREO
-5
0
LR
STEREO
GAIN -5
-10
OO
+6
OO
+6
OO
+6
OO
+6
EXT
IN
+6
+6
OO
+6
OO
+6
EXT
IN
OO
+6
OO
+6
OO
+6
OO
+6
GRP
PHONES
TALKBACK MIC
+6
OO
+6
OO
+6
OO
+6
1
GRP
2
OO
GRP
1
GRP
2
ST4
5
OO
1
GRP
0
OO
GRP
1
LR
DIRECT TO
ST2
5
GRP
16
OO
DIREC T TO
GAIN
10
-20
16
OO
EXT
IN
EXT
IN
ST3
5
-10
10
-20
GRP
2
TALKBACK
2
2TRK REPLAY
-10
10
-20
10
-20
16
OO
GRP
16
OO
AUX
1
+6
OO
4
2TRK
TO LR
POWER
OO
+6
OO
+6
OO
+6
OO
+6
OO
+6
GRP
OO
+6
OO
+6
OO
+6
OO
+6
OO
+6
GRP
5
OO
+6
OO
+6
OO
+6
OO
+6
OO
+6
GRP
5
OO
+6
OO
+6
OO
+6
OO
+6
OO
+6
OO
+6
OO
+6
OO
+6
MAX
GRP
GRP
6
5
GRP
6
R
+16
+9
+6
+3
0
-3
-6
-9
-12
-16
-20
-30
ON
GRP
6
L
PINK NOISE
1kHz OSC
GRP
5
+6
OO
M
6
+6
OO
MUTE
GRP
MUTE
GRP
7
GRP
7
L-R
GRP
7
+10
OO
MAX
OSC/NOISE
GRP
4
AUX
9-10
+6
OO
MIN
3
GRP
4
MIN
2
+6
OO
GRP
3
GRP
4
AUX
2
AUX
9-10
GRP
3
GRP
+6
OO
AUX
GRP
3
AUX
1
7
MTX1-2
PFL
PFL
GRP
GRP
8
GRP
8
PFL/AFL
GRP
8
8
MTX3-4
10
10
M
MONITOR
M
L
5
5
L-R
L
L
L
AUX
1-2
L-R
0
0
1-2
OO
+6
OO
+6
OO
+6
R
3-4
5
OO
+6
OO
+6
OO
+6
R
OO
+6
OO
+6
OO
+6
R
0
AUX
3-4
R
10
M
5
10
10
20
M
M
M
AUX
5-8
M
30
OO
OO
LEVEL
LEVEL
LEVEL
L-R
AUX
9-10
20
30
LEVEL
2TRK
LATCH
MTX1
TALK
+6
OO
+6
OO
MUTE
+6
OO
MUTE
STEREO
+6
OO
MUTE
MTX2
MUTE
MTX3
STEREO
MTX4
AUX
AUX
0
1
AUX
0
2
AUX
0
3
AUX
0
4
AUX
0
5
AUX
0
6
AUX
0
7
0
8
AUX
AUX
9-10
0
9-10
STEREO
OO
+10
OO
+10
AFL
AFL
REV
REV
OO
+ 10
OO
+ 10
AFL
OO
+10
OO
+10
OO
+10
OO
+ 10
AFL
AFL
AFL
AFL
AFL
REV
REV
REV
REV
REV
OO
MUTE
MONITOR
+10
MUTE GROUPS
REV
REV
ROTARIES
GRP1
TO M
GRP2
TO M
GRP3
TO M
GRP4
TO M
GRP5
TO M
GRP6
TO M
GRP7
TO M
GRP8
TO M
GRP1
TO LR
GRP2
TO LR
GRP3
TO LR
GRP4
TO LR
GRP5
TO LR
GRP6
TO LR
GRP7
TO LR
GRP8
TO LR
=
=
PAN
=
PAN
L
R
=
PAN
L
R
MUTE
=
PAN
L
R
MUTE
R
=
PAN
L
R
MUTE
R
PAN
L
R
L
R
OO
MUTE
MUTE
10
PK!
+6
0
SIG
PK!
+6
0
SIG
MUTE
MUTE
10
10
10
10
10
10
10
10
10
5
5
5
5
5
5
5
5
5
5
5
0
0
0
0
0
0
0
0
0
0
0
5
5
5
5
5
5
5
5
5
5
5
10
10
10
10
10
10
10
10
10
10
10
20
20
20
20
20
20
20
20
20
20
30
30
30
30
30
30
30
30
30
30
00
00
00
00
00
00
00
00
00
00
1
2
3
4
5
6
7
WEDGE
MODE
M
P/AFL
0dB
PK!
+6
0
SIG
PK!
+6
0
SIG
PK!
+6
0
SIG
MUTE
F OH
MONITOR
L-R TO M
=
PAN
L
PK!
+6
0
SIG
PK!
+6
0
SIG
MUTE
10
=
PAN
L
PK!
+6
0
SIG
PK!
+6
0
SIG
PK!
+6
0
SIG
PK!
+6
0
SIG
AUX MODE
FADERS
8
L
20
30
00
R
M
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:
Think before you hit
the switch!
•
Turn the amplifiers on last and off first.
•
Mute channels before plugging cables,
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.
unplugging
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!
28
GL2800 User Guide
USO RESTRITO
Dual Functionality Now an industry standard, Allen & Heath pioneered this
feature with the introduction of the first GL consoles in the ‘90s. In the past it was
necessary to stock two different types of live sound console, one for mixing FOH
(front-of-house), the other designed for mixing on-stage monitors. With the
introduction of a few clever ‘mode’ switches we changed all that. Now, the same
console can be quickly configured to carry out either task properly and without
compromise.
The GL2800 takes dual functionality a thoughtful stage further with the advent
of new engineering practices such as multi-media and IEM (in-ear monitor)
mixing, and computer based live multi-track recording. The key principles of
dual functionality are:
•
The same console can be quickly configured by the operator for proper FOH
or stage monitor mixing, or as a combination of both for mixing monitors
from FOH. In either mode, no part of the console is redundant. Every
control and socket can be used for an associated function.
Protected
•
To prevent accidental operation during the show, the configuration mode
switches are safely recessed under the panel.
Aux Reverse
•
In FOH mode the groups and LR are the main outputs while in Monitor
mode the aux mixes become the main outputs.
•
The REV switch swaps the group or L, R master controls with the related aux
master so that you have full fader control of the appropriate main output
complete with mute, AFL and LED bar meter.
•
In Monitor mode the aux outputs are routed to the console main XLR
sockets for electronically balanced drive, with inserts for patching in
processors such as graphic EQ, limiters and delays.
•
Channel pre/post switches and link options are important. In Monitor mode
it must be possible to switch all auxes post for channel fader mastering. For
Monitors from FOH, the pre-insert, pre-EQ or post-EQ option is needed.
Note that per channel pre switching is best as you may occasionally need to
mix in some post sources such as radio mics and sound effects.
•
In Monitor mode the groups continue to feed the sub grouping to LR so that
you can still work with grouped level control to the main mix.
•
In Monitor mode the groups and LR continue to feed the matrix so that you
can create independent mixes in addition to the auxes for special feeds,
recording, and further mono or stereo in-ear monitors.
•
In Monitor mode the M output becomes the engineer’s ‘listen wedge’ feed
providing the PFL/AFL mix. It gives the engineer identical fader control and
XLR drive for all wedges including their own.
•
In both modes assignable talkback is provided.
•
The matrix has a useful application in both modes. External ambience
sources can be mixed in to the matrix to create live recording and in-ear
monitor mixes. A mono aux can be converted to stereo IEM.
FOH / Monitor
Master Control
XLR + Inserts
Pre/Post
Sub Grouping
Matrix Feed
Listen Wedge
Talkback
FOH
Monitor
Recording
LR + M mixes
14 Monitors
Stereo / Mono
Subs on M mix
8 Aux (wedge)
2-Track
LR to M for mono
2 Aux (stereo IEM)
8 Groups
8 Sub Groups
4 Matrix (2 stereo IEM)
4 Matrix
10 Auxes
Engineer’s Wedge
Direct Outputs
4 Matrix
Ambience, Talkback
Ambience
GL2800 User Guide
29
USO RESTRITO
Applications for the Matrix
EXT
IN
EXT
IN
+6
OO
GRP
EXT
IN
+6
OO
OO
GRP
1
+6
OO
+6
OO
+6
OO
GRP
OO
+6
OO
+6
OO
OO
+6
OO
+6
OO
GRP
+6
OO
+6
OO
GRP
+6
OO
+6
OO
+6
OO
+6
OO
+6
OO
+6
OO
OO
+6
OO
+6
OO
+6
OO
+6
OO
+6
OO
+6
OO
+6
M
+6
LEVEL
OO
MUTE
OO
R
OO
+6
OO
MUTE
+6
M
LEVEL
LEVEL
+6
L
+6
OO
+6
8
R
M
OO
GRP
OO
+6
OO
M
+6
L
R
+6
7
OO
+6
OO
GRP
8
OO
R
+6
GRP
L
+6
LEVEL
+6
MUTE
OO
+6
MUTE
MAX
PINK NOISE
1kHz OSC
ON
M
L-R
MTX1-2
MTX3-4
Talkback
and
alignment
AUX
1-2
AUX
3-4
0
AUX
9-10
10
M
LATCH
L-R
TALK
2TRK
MTX1
STEREO
MTX2
MTX3
STEREO
MTX4
AUX
9-10
MONITOR
Remote Broadcast
Create a mono or stereo feed as described
above. Use the tone generator to send a ‘slate’ signal to the
destination for line-up.
Zone Feeds Send independent relay feeds to additional locations
such as the foyer, dressing rooms, cry room, balcony and so on. You
can use the groups to adjust the balance to suit the destination, for
example to boost the orchestra against the vocals. Feed the output
through an EQ to tune the speaker for the local acoustics.
Hearing Assist It is a growing requirement that venues provide a
hard-of-hearing inductive loop, IR or wireless broadcast for the hearing
impaired audience. The matrix is ideal for this application as you can
combine a stereo LR mix into mono, add groups to help vocal
intelligibility, patch in an external ambience source, and add
processing such as EQ and limiters which may be needed.
MONITOR
AUX
5-8
Stereo Recording Raise L to the unity 3 o’clock position in one
matrix, R in another to create a stereo pair that follows the LR mix.
You can adjust the balance to compensate for the acoustic sound in
the room using the groups, and even add audience ambience
(described later).
Delay Fill Speakers Use the matrix to feed additional fill speakers for
distributing the sound more evenly around a large venue, for example
centre fill, stage front fills, under balcony or rear fills, or ‘mix island’
delay tower at a festival. To aid intelligibility for the nearby listeners
without moving their focus from the stage, the send should be delayed
using an in-line delay processor. As a rule of thumb, delay 1mS per
foot difference between the listener and the fill and the listener and the
main speakers. Now add a few milliseconds ‘Haas effect’ delay so the
listener hears the main speakers slightly before the fill. Keep the fill
level about 10dB or so below the main PA sound at that location. It
may help intelligibility to boost the vocals above the instruments in the
fills, and to use an EQ to cut the extreme LF and HF frequencies.
OSC/NOISE
MIN
Mono Recording
If you are working with a stereo PA you can
combine L and R into a matrix output to produce a mono mix feeding
a recorder, video camera and so on. Raise the L and R rotaries to the
2 o’clock position to sum them together. You can use the built-in
1kHz tone generator to feed a line-up tone to the connected recorder.
6
OO
+6
OO
OO
GRP
7
8
L
+6
GRP
GRP
8
+6
5
OO
+6
OO
OO
GRP
6
7
GRP
+6
GRP
GRP
7
+6
4
OO
+6
OO
OO
GRP
5
6
GRP
+6
GRP
GRP
6
+6
3
OO
5
OO
GRP
4
GRP
5
+6
GRP
4
+6
2
3
GRP
4
OO
GRP
GRP
3
GRP
+6
2
GRP
3
+6
1
GRP
2
OO
GRP
1
GRP
2
+6
GRP
1
GRP
EXT
IN
The matrix is a ‘mixer within a
mixer’, a versatile toolbox of outputs you can use to satisfy a host of
applications. Each of the 4 outputs is mixed from any combination of
the groups, L, R, M and an external input as dialled up on the 12
source rotaries (hence a ‘12x4’ matrix). Its master level can be
adjusted independently. Using combinations of the outputs you can
create mono, stereo or multiple output mixes. Some applications
include:
Stereo
monitoring
Additional Monitor Mixes You can use the matrix to create some
additional monitor mixes when you run out of auxes, this time made
up from a mix of the groups, LR and external input. The LR could be
used to create a general overall balance, and then the groups added
according to musician preference. Groups could be routed from 'me
only' channels associated with each musician, or traditionally grouped
sources. The musician could get a balance from, say, the overall
stereo mix, drums, brass, keyboards, ‘me only’ and ambience, a very
quick way of mixing. You could also use the EXT IN to add ambience
pickup, very useful if you are creating in-ear (IEM) mixes. Use two
matrices to create stereo monitor feeds.
Combining Two Consoles into a Single PA In a festival situation
you may have a support band wishing to patch in their own console.
One way to do this is to feed the PA from a pair of matrices, and then
use EXT Inputs to combine the external console with the main LR mix.
30
GL2800 User Guide
Create IEM Mixes with Ambience
MIC OUT
MIC OUT
(BREAKPOINT)
(BREAKPOINT)
MATRIX EXT IN
MTX
IN
4
MTX
IN
3
MTX OUT
4
MTX
IN
2
MTX OUT
3
MTX OUT
2
ST4 IN
(COMMON)
MTX
IN
1
L/M
MTX OUT
1
ST3 IN
L/M
ST2 IN
L/M
ST1 IN
STEREO LINE IN
L/M
STEREO LINE IN
L/M
L/M
LAMP
R
R
R
MIC IN
RT
INSERT
8
INSERT
7
INSERT
6
INSERT
5
INSERT
4
INSERT
3
INSERT
2
INSERT
1
AUX (L)
9
AUX (GRP)
8
AUX (GRP)
7
AUX (GRP)
6
AUX (GRP)
5
AUX (GRP)
4
AUX (GRP)
3
AUX (GRP)
2
AUX (GRP)
1
USO RESTRITO
(R)
INSERT
L
8
GRP (AUX) 7
GRP (AUX) 6
SEND
MIC IN
INSERT
(GRP/AUX REVERSE)
GRP (AUX) 5
GRP (AUX) 4
GRP (AUX) 3
GRP (AUX) 2
GRP (AUX) 1
RETURN
USE ON
ALLEN
TIP
RING
DC POWER IN
A
In Monitor mode the
matrix continues to be fed with the 8 groups, L, R and M mixes. You
can use these to create additional, independent monitor mixes.
Together with the auxes these give you as many as 14 mixes. Create
mono or stereo in-ear monitor feeds using single or paired matrices,
for example MTX1-2 and 3-4. You could use LR to start with a basic
stereo mix, then add up to eight instrument or ‘more me’ groups. Add
ambience using a pair of jack leads to patch the stereo channel MICs
into matrix EXT IN 1 and 2. With nothing plugged into EXT IN 3 and 4
the two mic signals are automatically linked across making the same
stereo ambience available to both IEM mixes. Alternatively you could
use an outboard reverb effects processor fed from a post-fade aux
send to create the ambience. Use the channel faders and pan to
create the basic stereo mix. Remember to set the other monitor aux
sends to pre-fade.
Using the Matrix to create a Recording The band may be
acoustically loud in the room, and you need only mix vocals and some
of the instruments into the PA to get good clarity and overall balance
for the listeners. If you recorded the console main output you would
be disappointed when you got home and listened to the result. For
example, there may be strong voices, acoustic guitar and flute, but the
drums, bass and electric guitar may be low. This is because you did
not need much of these backline instruments in the PA mix. However,
if you use the matrix to feed the recording you could start with the
main LR (PA) mix, then turn up the drum and guitar groups to
compensate for the lack of these in the house system. You could also
add in ambience as described above to give the recording more life
by including audience reaction and natural reverberation.
AUX
Recording with the GL2800
1
+6
OO
AUX
2
PRE-EQ
AUX
3
OO
+6
OO
+6
AUX
4
POST
PRE
AUX
5
OO
+6
OO
+6
OO
+6
OO
+6
AUX
The console is equally at
home recording live or in the project studio. The studio grade
preamps produce an accurate and noise-free recording. Create a
stereo recording from the main LR output, or from a pair of matrices as
described above if recording and mixing live at the same time. To
record to multitrack use whichever combination of groups, matrix,
auxes and channel direct outputs is most convenient. The direct
outputs are set pre-fade as factory default. This setting means that the
recording is not affected by your live fader and EQ changes. Note that
you can swap internal jumpers to change this to post-fade if you
prefer. Set the channel pre-EQ switches as required. Remember to
use some ambience microphones to record the audience and venue
atmosphere too.
6
AUX
7
AUX
8
POST
PRE
AUX
9-10
STEREO
OO
=
+6
PAN
L
R
POST
PRE
GL2800 User Guide
Pre/post Fade Aux Settings The aux sends are switched pre
or post fader using three PRE switches on every channel. One switch
affects auxes 1-4, another auxes 5-8, and one for stereo aux 9-10. It is
usual to set auxes pre-fade if you are mixing monitors from FOH. Set
post-fade for auxes used as effects sends, zone feeds, aux-fed subs
and so on. If you are using the console to mix monitors only then the
auxes are typically set post-fade so that the channel fader becomes
the source master to all monitors. In this case start with all channel
faders set to ‘0’.
There are times when you may want some monitor sends set postfade while most are set pre-fade, for example mixing monitors with
radio mics and cued sound effects. Here, it may be better for the
radio mics to follow your fader movements so avoiding off-stage chat
or noise in the monitors. For this reason we believe it is important
that channel rather than global mix pre/post switching is provided.
31
USO RESTRITO
Mix and Aux-Fed Subs Driving the PA system sub bass
speakers with their own mix has two main advantages. First, the mix
is much cleaner because only sources that generate the low
frequencies, for example kick drum, bass guitar, keyboards and
sound effects are sent to the subs. Low frequency bleed from these
sources into open microphones such as vocals and snare is
eliminated from the PA much more effectively than using just the
channel filters. Second, the sub bass amplifier is only working with
the sources needed. It is not wasting power reproducing unnecessary
pickup.
10
10
10
10
20
20
20
20
30
30
30
30
00
00
00
00
8
L
R
M
L R SUBS
TOPS
Another method that has become popular is to use an Aux mix to
drive the subs. This is referred to as ‘aux-fed subs’. Align the system
so that the normal unity gain position of the channel fader and aux
send result in the correct speaker balance. For sources you wish to
send to the sub, turn up the channel aux send to its unity 3 o’clock
position. Avoid the temptation to ride the aux send to create more or
less sub as this may upset the natural speaker balance or cause
problems for listeners in different parts of the room.
GRP8
AUX
AUX
8
9-10
STEREO
OO
+10
OO
+10
MUTE
AFL
REV
REV
GRP8
TO M
GRP8
TO LR
L-R TO M
=
PAN
L
R
PK!
+6
0
SIG
OO
0dB
PK!
+6
0
SIG
PK!
+6
0
SIG
PK!
+6
0
SIG
MUTE
MUTE
AFL
GRP8
L
AUX8
AUX9-10
10
10
R
10
M
5
5
5
5
0
0
0
5
5
5
5
10
10
10
10
20
20
20
20
30
30
30
30
00
00
00
AUX8
SUBS
L
00
R
L
LISTEN
10
0
8
The subs can be separately driven in several ways. A common
method is to use the independent M mix. Route all sources to L-R.
Route the sources you want in the subs to both L-R and M. Feed the
LR to a stereo crossover to drive the top speakers, and M to a mono
crossover to drive the sub speakers. Refer to the speaker
manufacturer for recommended crossover frequency, usually within
the range 80Hz to 120Hz. The PA overall level is adjusted by moving
the L, R and M (sub) master faders together.
M
R C
TOPS
OUT
M (WEDGE)
One problem with using the aux in this way is that it becomes difficult
to balance the top and sub speakers if you need to adjust the overall
volume of the PA. Typically the LR (tops) use fader masters, and the
aux is on a rotary master. The GL2800 overcomes this with the
monitor mode ‘REV’ switch that swaps the rotary aux master with the
related fader group master. This switch is recessed for protection
against accidental operation. This puts the aux (sub) master on to a
fader next to the PA tops master faders. The result is you get all
master faders aligned for simultaneous control, individual mutes and
meters, and three properly balanced XLR outputs. We recommend
that you use Aux 8 for the sub feed. This gives you 4 master faders
next to each other, for example, Subs, L, R and C.
Other M Output Applications Apart from the main PA C mix
or sub-bass speaker mix, other examples include L+R sum mono fill,
additional mono zone feed, mono recording, mono PA with LR
providing two more subgroups to M, engineers PAFL wedge feed…
and more.
Using the channel Direct Outputs
DIRECT
OUT
Recording - Default factory setting is pre-fade so that your live fader
mixing does not affect the recording. Use the channel recessed PREEQ switches to select either post-EQ or pre-insert, pre-EQ for your
recording. Post-EQ lets you use the EQ for source correction affecting
the recording too. Select pre-EQ if you do not want your compressor
and EQ to affect the recording.
Monitor mixing - You could also patch DIR OUT into a matrix EXT IN
to add a ‘more me’ channel into a monitor send created from the
groups and LR. If preferred you can reconfigure the direct outputs to
post-fade by setting internal jumpers.
Single effects - Use post for feeding an effects processor with one
source only, for example a dedicated reverb on lead vocals or snare.
32
GL2800 User Guide
USO RESTRITO
MIC OUT
MIC OUT
(BREAKPOINT)
(BREAKPOINT)
STEREO LINE IN
L/M
STEREO LINE IN
L/M
R
The mic preamp has a TRS jack MIC OUT breakpoint so that its output
can be used independently. Plugging into this socket breaks the
signal path feeding the channel and routes it to the jack instead. ST1
and ST3 stereo inputs can be routed either into the return channels or
directly to the LR mix. This is configured using recessed mode
switches which protect from accidental operation during a show.
R
MIC IN
Using the Stereo Channels
The two full feature stereo
channels and the two dual stereo returns present a unique flexibility.
The channels each include a patchable mic input and a stereo line
input. The returns each include two stereo inputs which can be mixed
together or used separately.
MIC IN
The GL2800 provides 6 stereo inputs in a compact format.
Together with the 2 mics the stereos provide for a host of space
saving applications:
ST4 IN
L/M
ST3 IN
L/M
ST2 IN
L/M
ST1 IN
L/M
Standard Mono Microphone Channels Mono mic input through the
stereo channel with 4band EQ, auxes and full routing.
True Stereo Microphone Channel
For example, use short jack
leads to patch both MIC OUT breakpoints into the stereo line input of
one channel. Set the stereo line level control on this channel to its
‘0dB’ position. Adjust the gain and balance between the left and right
microphones using the two mic GAIN controls. The other channel can
be used as a stereo effects return, sound effects or other line source.
R
Mixing Two Microphones through One Channel Patch one MIC
OUT into the other channel stereo L/M input. On that channel turn up
the mic gain control to add its own mic, and the stereo line level
control to add the patched mic.
Patchable Microphone Preamplifier
Plug into the MIC OUT
breakpoint to disconnect the mic preamp from the channel and patch
it elsewhere to be used independently. For example, plug in a room
microphone and patch MIC OUT to a matrix EXT IN to add ambience
to a recording or monitor feed, or use it as a preamplifier for a
reference microphone with an RTA or other analysis equipment. You
could even use it to provide a better mic source to a video camera or
other recorder.
Dual Stereo Line Inputs A trademark of Allen & Heath consoles is
the ability to combine more than one source into a stereo channel,
each with its own level control. This can save channel space when
working with two similar sources routed to the same destination, for
example, two stereo reverb returns, two backing track or sound effects
players, or to alternate between walk-in music and recorded
announcement players. The two stereo return channels provide this
facility.
MUTE GROUPS
Using the Mute Groups
The 4 mute groups let you
simultaneously mute combinations of input channels with a single key
press. For example, use a group to mute all the drum channels, or all
stage mics in a musical production. You could also assign a group to
mute all channels during the intermission. You could even use the
groups to recall the correct channel settings for different bands or
scenes during a theatre show.
Finally… A Note about Combining Signals You can use a
‘Y’ splitter cable or adapter to feed one output to two destinations, but
never try to combine two outputs to one destination. This may
damage or degrade the performance of the equipment driver stage.
GL2800 User Guide
33
Specifications
USO RESTRITO
Performance
Maximum input level
Mic
CH Line
Other Line
+34dBu (inc pad)
+34dBu
+20dBu
Maximum output level
XLR
Jack
Internal headroom
Channels
Mix
Meters
Sensitivity
Master meters
Channel meters
3 colour, quasi peak response
0VU = +4dBu at XLR output
12 segment
-30 to +16dB
4 segment
-12,0,+6+16dB (5dB before clip)
Frequency response
20Hz to 50kHz
Mic CMRR at 1kHz
> 80dB typical
THD+n at +14dBu 1kHz
Mic to mix out < 0.003%
Crosstalk at 1kHz
Fader shutoff
Mute shutoff
Inter channel
Noise, rms 22Hz to 22kHz
Mic EIN -128dB
Residual output noise
< -96dBu (-100dB S/N)
LR mix noise 24 routed
< -86dBu (-90dB S/N)
Group mix noise 16 routed < -86dBu (-90dB S/N)
Aux mix noise 16 routed < -92dBu (-90dB S/N)
Mix noise 24 line 0dB gain < -86dB S/N
Channel HPF
12dB/octave below 100Hz
Mono EQ
HF
HM
LM
LF
Shelving +/-15dB, 12kHz
Peak/dip +/-15dB, 500Hz to 15kHz, Q=1.8
Peak/dip +/-15dB, 35Hz to 1kHz, Q=1.8
Shelving +/-15dB, 80Hz
Stereo EQ
HF
HM
LM
LF
Shelving +/-15dB, 12kHz
Peak/dip +/-15dB, 2.5kHz, Q=1.8
Peak/dip +/-15dB, 250Hz, Q=1.8
Shelving +/-15dB, 80Hz
Power supply
External RPS11
IEC input
External Input for optional RPS11 backup supply
+26dBu
+20dBu
+20dB
+22dB
+/-0.5dB
>90dB
>88dB
>90dB
Mechanical
24
Width
Depth
Height
944mm (37.2”)
650mm (25.6”)
170mm (6.7”)
Weight 29kg(63.8lbs)
34
32
40
48
56
1171mm (46.1”) 1398mm (55”)
1625mm(64”)
1852mm(73”)
35kg(77lbs)
47kg(103.4lbs)
53kg(116.6lbs)
41kg(90.2lbs)
GL2800 User Guide
USO RESTRITO
Connections
Mono channel
XLR balanced pin 2 hot
TRS balanced, tip hot
Total gain range
Pad out (MIC)
Pad in (MIC or LINE)
Max input level
XLR phantom power
Sensitivity -60 to +14dBu
Sensitivity -40 to +14dBu
74dB
2k ohm
>10k ohm, -20dB attenuation
+34dBu
+48V, on/off
Stereo channel
Mic in
Stereo in
Same as mono channel
TRS balanced >10k ohm, -16 to +20dBu
Stereo return
ST1/3
ST2/4
TRS unbal >10k ohm, -16 to +20dBu
TRS balanced >10k ohm, -16 to +20dBu
Talkback mic
XLR balanced pin 2 hot
Phantom power
Sensitivity -50 to -10dBu
Internal jumper +48V (fitted)
2-track return
TRS unbalanced
>4k ohm, -2dBu
2-track send
TRS impedance balanced <75 ohm, -2dBu
Inserts
Channel
Output
L, R, M outputs
XLR balanced pin 2 hot
<75 ohm, +4dBu, +26dBu max
Group (aux) out
XLR balanced pin 2 hot
<75 ohm, +4dBu, +26dBu max
Aux 1-10 output
TRS impedance balanced <75 ohm, -2dBu, +20dBu max
Electronic balance option <75 ohm, +4dBu, +26dBu max
Direct out
TRS impedance balanced <75 ohm, 0dBu, +20dBu max
Matrix out
TRS impedance balanced <75 ohm, -2dBu, +20dBu max
Electronic balance option <75 ohm, +4dBu, +26dBu max
Headphones
Monitor out
Talkback/osc out
TRS, tip L, ring R, 30 to 600 ohm headphones recommended
TRS impedance balanced <75 ohm, -2dBu, +20dBu max
TRS impedance balanced <75 ohm, +20dBu max
Lamp
4-pin XLR
TRS, tip send, ring return, 0dBu
TRS, tip send, ring return, -2dBu
max 12V 5W lamp
GL2800 Series Part Numbers
22 mic/line, 2 mic/stereo, 8 group console
30 mic/line, 2 mic/stereo, 8 group console
38 mic/line, 2 mic/stereo, 8 group console
46 mic/line, 2 mic/stereo, 8 group console
54 mic/line, 2 mic/stereo, 8 group console
GL2800-24/v
GL2800-32/v
GL2800-40/v
GL2800-48/v
GL2800-56/v
Sys-Link V2 input/output option kit
GL2800-SLV2
SSM2142P balanced output driver option IC
AE0302
DRV134 balanced output driver option IC (alternative to above) AE5725
GL2800 User Guide
Allen & Heath RPS11 power supply
RPS11/v
Allen & Heath 18” gooseneck LED lamp – right angled
LEDLAMP-X
35
MUTE 1-4
AUX 1-10
GRP 1-8
LR
M
PFL/AFL
System Block Diagram
GL2800
SYS-LINK CONNECTION
SL
PHANTOM POWER
METER
4 BAND EQUALISER
AFL
PFL
48V
GRP/AUX REV
HF
MUTE
GAIN
MIC
LINE/PAD POL
-20dB
2= +
BALANCED
+
-
PAN
EQ IN
L-R
FADER
LINE
INSERT
0dBu
USO RESTRITO
METER
FADER
AFL
+10dB boost
GRP MIX
SL
INSERT
PRE
PRE-FADE A
TIP= +
PRE
PRE
2=+
+4dBu
M2
JUMPER C D E
POST SW PR
POST-FADE B
RING= -
GROUP OUT
BAL
MUTE
-2dBu
M1
MIC/MONO INPUTS
0dBu
7-8
PRE-INSERT, PRE-EQ
IMPEDANCE BALANCED
-2dBu
+4dBu BAL OPTION
5-6
RING= RETURN
DIRECT OUT
TIP= +
GROUPS / AUX 1-8
3-4
LF
TIP= SEND
AUX OUT
+10dB boost
AUX MIX
1-2
LM
TIP= +
AUX
SL
M
HM
HPF
AUX
9-10
1
3
2
5
4
7
6
8
M
M3
PAN
L-R
M4
PAN
GRP (TO MATRIX)
IMPEDANCE BALANCED
-20dB
+
-
HF
SUM +
LM
+
LF
+
+
PRE-FADE
Off to +20dB boost
LRM / AUX 9-10
5-6
7-8
POST-FADE
GAIN
IMPEDANCE BALANCED
-2dBu
+4dBu BAL OPTION
PRE
PRE
1
3
5
4
7
6
8
2=+
+4dBu
M MIX
SL
M4
2
+4dBu
RIGHT OUT
BAL
MUTE
-2dBu
M3
9-10
2=+
M
INSERT
SL
M2
JUMPER C D E
POST SW PR
LEFT OUT
BAL
MUTE
R
-2dBu
PRE
METER
FADER
+10dB boost
LR MIX
M1
INSERT
BAL
-2dBu
MONO OUT
BAL
MUTE
2=+
+4dBu
M (TO MATRIX, MONITOR)
FROM P/AFL MIX
WEDGE MODE
TB WEDGE DIM
CH
MUTE
FROM L,R
MONITOR OUT
FROM MATRIX
L
1-2 (3-4)
FADER
2-TRACK
SEND
RETURN
POST-FADE
G
PRE-FADE
F
GAIN
+
SUM
AUX
DUAL STEREO RETURN x2
1
2
R
PFL/AFL
2TRK TO LR
IMPEDANCE BALANCED
L/M
L
PHONES OUT
-2dBu
R
R
INPUT ST2(4)
+
-
MONITOR
FROM M FROM AUX9-10
L-R
+
LR
R
SUM +
MONITOR
L
R
AUX9-10
M
M
SUM +
GAIN
MTX3-4
MTX4
MTX1-2
ALL UP = P/AFL ONLY
PFL
INPUT ST1(3)
R
L
INSERT
SL
AUX
TIP= +
R (TO MATRIX, MONITOR, MONO)
3-4
+
-
+
-
+
1-2
FADER
MIC/STEREO INPUTS x2
L/M
AUX10 OUT
AUX10 (TO MONITOR)
L (TO MATRIX, MONITOR, MONO)
RING= -
L/M
LR TO MONO
L-R
STEREO LINE
R
AUX9 (TO MONITOR)
M
BAL
EQ IN
HM
IMPEDANCE BALANCED
+4dBu BAL OPTION
-2dBu
+10dB boost
MUTE
HPF
TIP= +
+
-
TIP= +
SL
PFL
4 BAND EQUALISER
MTX3
L/M
LINE/PAD POL
MUTE
MTX2
0dBu
(break jack)
GAIN
AUX9 OUT
AUX9-10
AUX9-10 MIX
MTX1
MIC OUT
PHANTOM POWER
2TRK
2= +
SL
METER
48V
L-R
MIC
LR/AUX9-10 REV
9-10
PFL/AFL MIX
3
2
TO WEDGE MODE
SL
1
SL
TIP = LEFT
RING = RIGHT
PFL/AFL DC
FROM GRP 1-8
MUTE MASTERS
ON
2= +
1kHz OSC
+
-
GRP4
L-R
PRESS TO TALK
GRP7
MTX3-4
AUX9-10
2
3
4
0dBu
L
R
TO MONITOR
M
MATRIX MIX
LEVEL
MUTE
MATRIX OUT
+6dB boost
TIP= +
GRP8
AUX3-4
AUX5-8
36
GRP6
MTX1-2
AUX1-2
LATCH
1
EXT IN
GRP5
M
WEDGE DIM
BALANCED
GRP3
M4
DIM
GAIN
TALKBACK
MIC IN
LEVEL
GRP2
M3
IMPEDANCE BALANCED
PINK NOISE
48V PHANTOM POWER
H
J
OFF
ON
M1
M2
TB/OSC OUT
TB/OSC
FROM LRM
GRP1
+4dBu BAL OPTION
TB
IMPEDANCE BALANCED
-2dBu
MATRIX 1-4
GL2800 User Guide
User Options
The GL2800 has a versatile architecture which should satisfy most
applications you may encounter without modification. However, the following
internal options provide alternative settings for those applications that may
demand them. Access is required to the internal assemblies. For user
convenience, pluggable jumper links are used in most places.
Do not adjust the user options while power is applied to the console.
Do not remove or tamper with the internal power unit, its cover or wiring.
USO RESTRITO
Remove the base Switch off power and unplug the power unit and all the
cables. Invert the console on a flat, clean, well lit surface. Use Torx (star head)
screwdrivers to remove the screws holding the base to the chassis. Use a T15
driver to remove the set of 6Bx5/16 screws holding the base to the rear and
underside of the chassis. Carefully lift off the base.
Configure the internal options Fit any options required referring to the
instructions provided. Set the option jumpers to the required positions. Make
sure they are pressed fully home. Check that all channels are correctly set and
all options fitted according to their instructions. Make sure that no debris or parts
are left loose inside the console.
Refit the base Carefully reposition the base. Refit the fixing screws.
IMPORTANT: Check carefully that all channel jumpers are correctly set
as required. Errors on one or more channels now may cause user problems
later. We recommend that you write the repositioned jumper settings on a label
and adhere this to the rear panel. This would provide a helpful reference to other
users of the console.
MONO INPUT
STEREO INPUT
MASTER L
GROUP 1&3
GROUP / MTX
GROUP 2&4
R103
U5
R102
R83
AUX 1-2
PRE/POST FADER
U9
U5
R82
R52
R51
R51
R170
R169
R 168
U1 4
R167
ON
J P2
JP1
AUX 5-8
BALANCE
+48V
OFF
AUX 1-2
PRE/POST FADER
MATRIX 1-4
BALANCE
U15
AUX 2/4
BALANCE
AUX 1-2/9-10
PRE/POST FADER
U5
DIRECT OUT
PRE/POST FADER
R52
AUX 1/3
BALANCE
AUX 10
BALANCE
TB MIC
+48V
AUX 9
BALANCE
GL2800 User Guide
37
2
Aux pre/post EQ For convenience, this option
PRE-EQ
AUX
3
MONO CHANNEL
JUMPER
E D C B A
PR
PO
PO
PR
AUX 1-2
SW
PR=PREFADE
SW=SWITCHED
PO=POSTFADE
is a recessed front panel switch per channel. No
internal access is required. The up position is postEQ, pressed is pre-insert and pre-EQ. Note that this
setting affects all pre-fade sends from the channel,
including auxes and direct output.
+6
OO
DIR OUT
CN4
Direct output source
Factory default is prefader.
This is common for live recording to
multitrack. The live mix fader movements do not
affect the recording. Move the jumper from PR to
PO to change to post-fade. Post-fade is appropriate
when using the output as a direct channel effects
send.
MONO CHANNEL
JUMPER
E D C B A
PR
PO
PO
PR
AUX 1-2
SW
PR=PREFADE
SW=SWITCHED
PO=POSTFADE
DIR OUT
CN4
STEREO CHANNEL
SW
AUX 1-2
JUMPER
E D C
PO
JP1
PR=PREFADE
SW=SWITCHED
PO=POSTFADE
PR
USO RESTRITO
AUX
Channel Aux pre/post settings
Factory
default is Aux 1-4 = switched, Aux 5-8 = switched,
Aux 9-10 = switched pre/post fader.
You can
change the setting of Aux 1-2 from switched to
permanently pre-fade or post-fade if preferred.
Make sure you set all mono and stereo channels the
same. To avoid possible future confusion when the
console is used by other operators, we recommend
you only change these settings if absolutely
necessary.
CN4
Return Aux pre/post settings
STEREO RETURN
PR=PREFADE
PO=POSTFADE
AUX 1-2/9-10
L MASTER
+48V
OFF
JP1
ON
JP2
G G
PO
F F
PR
The stereo
returns feed Auxes 1, 2 and 9-10. Factory default is
the post-fader so that the fader becomes a master
for all feeds from the return. This may be changed
to pre-fade if you prefer. Move the two jumpers from
G to F.
Talkback mic +48V Factory default is +48V
phantom power turned on for the front panel
talkback mic XLR input. The option jumper is behind
the TB mic XLR on the L Master board. If you prefer,
phantom power can be disabled by repositioning the
jumper to the OFF position.
Note that phantom power should not harm nonpowered dynamic microphones as long as balanced
connections are used.
WARNING: Do not connect unbalanced
sources or cables to inputs with phantom power
selected. To avoid loud clicks do not press the
TALK switch when plugging or unplugging the
talkback microphone.
38
GL2800 User Guide
Output balance options The aux and matrix
MASTER L
GROUP 1&3
GROUP / MTX
R103
U5
R102
R83
U9
U5
R82
R52
R51
R52
AUX 1/3
BALANCE
U5
R51
MATRIX 1-4
BALANCE
R1 70
R 169
R168
U 14
R1 67
ON
J P2
JP1
AUX 5-8
BALANCE
+ 48V
O FF
AUX 1-2/9-10
PRE/POST FADER
AUX 2/4
BALANCE
U 15
USO RESTRITO
GROUP 2&4
outputs are impedance balanced as standard
operating at nominal -2dBu and with +20dBu
maximum drive. They provide similar interference
rejection to electronically balanced outputs when
connected to balanced equipment inputs.
An
electronically balanced option is available if you
require nominal +4dBu and higher output drive up
to +26dBu over very long cable runs. However, it is
not usually necessary to fit this option as the
impedance
balanced
drive
satisfies
most
applications. Check that you really need the option
before fitting it.
AUX 10
BALANCE
AUX 9
BALANCE
SLAVE CONSOLE
For each aux master, snip the legs of the two zero
ohm resistor links next to the IC socket. This
removes them from the circuit. Now simply plug the
option IC into the socket. Observe the correct IC
pin1 orientation and make sure its legs are correctly
aligned with the socket. Test the output once the
work is complete. You should measure the same
level but opposite polarity signal between + (hot)
and ground, and – (cold) and ground.
Sys-Link V2 input/output option
SYS-LINK V2 OUTPUT
A
TB MIC
+48V
There are two balanced driver ICs which may be
used. Either is suitable. These are available from
Allen & Heath or good electronic component
suppliers. The Allen & Heath part number is shown
below:
SSM2142P
A&H Part AE0302
DRV134
A&H Part AE5725
B
37WAY CABLES
A blank
plate is fitted in both positions as standard. This
may be replaced with optional cards which provide
the console inputs, outputs and PFL system on pairs
of 37way D connectors for linking to other Allen &
Heath consoles already fitted with Sys-Link V2. The
GL2800 can become an input channel expander
(slave) or have its number of input channels
expanded (master) when linked to other consoles.
Two 37way cables are required to link
GL2800 with another console.
the
The 37way shielded multi-core cable carries the
balanced, line level mix signals and PFL/AFL system
to or from the other console.
IMPORTANT: Note that you need 37 to 25way
adapter cables if you are connecting Sys-Link V2
(Version 2) to the older Sys-Link V1 (Version 1)
standard.
A
B
SYS-LINK V2 INPUT
MASTER CONSOLE
GL2800 User Guide
For full details please refer to the Sys-Link option
Applications Note AP6284 and Fitting Instructions
AP6159.
39
Cue Sheet 1 of 3
GL2800
Copy and use this page to record your console settings.
GL2800
DUAL STEREO RETURN
STEREO
GAIN -5
0
-10
0
LR
-10
GAIN -5
-20
LR
+6
+6
OO
1
GRP
AUX
2TRK
TO LR
4
POWER
+6
OO
GRP
5
+6
OO
MAX
R
L
PINK NOISE
1kHz OSC
GRP
5
+6
OO
GRP
5
+6
OO
GRP
6
+6
+6
+16
+9
+6
+3
0
-3
-6
-9
-12
-16
-20
-30
GRP
6
OO
+6
OO
+6
OO
+6
GRP
6
M
6
+6
OO
+6
OO
MUTE
GRP
MUTE
+6
OO
+6
OO
GRP
7
GRP
7
+10
OO
ON
9-10
OO
+6
MAX
GRP
4
GRP
5
AUX
OO
MIN
OSC/NOISE
+6
OO
9-10
+6
3
+6
GRP
OO
GRP
+6
OO
2TRK REPLAY
TALKBACK
MIN
+6
OO
2
OO
+6
GRP
OO
4
OO
+6
OO
AUX
2
+6
GRP
4
+6
OO
AUX
+6
3
OO
+6
2
GRP
3
OO
GRP
OO
GRP
3
+6
OO
2
+6
+6
1
GRP
OO
GRP
16
+6
OO
2
OO
GRP
1
GRP
OO
AUX
1
+6
OO
2
10
OO
PHONES
TALKBACK MIC
+6
OO
GRP
1
GRP
ST4
5
-20
16
OO
AUX
EXT
IN
+6
OO
GRP
1
0
-10
10
EXT
IN
+6
GRP
DIRECT TO
STEREO
ST2
5
EXT
IN
OO
10
16
OO
DIRECT TO
STEREO
GAIN -5
EXT
IN
ST3
5
-20
16
OO
0
-10
10
-20
USO RESTRITO
DUAL STEREO RETURN
STEREO
GAIN -5
ST1
5
L-R
GRP
7
7
MTX1-2
PFL
PFL
10
M
+6
OO
GRP
8
PFL/AFL
GRP
8
8
MTX3-4
MONITOR
+6
OO
M
+6
OO
L
5
5
+6
OO
GRP
8
10
L-R
+6
OO
GRP
+6
OO
L
L
OO
+6
OO
+6
L
AUX
1-2
L-R
0
0
1-2
+6
OO
R
3-4
5
5
10
10
20
20
30
30
OO
OO
+6
OO
R
R
+6
OO
+6
OO
+6
OO
M
+6
M
+6
OO
LEVEL
+6
OO
M
OO
LEVEL
R
+6
OO
M
+6
OO
+6
OO
LEVEL
LEVEL
0
M
AUX
5-8
L-R
AUX
9-10
2TRK
LATCH
MTX1
TALK
+6
OO
+6
OO
MUTE
MUTE
+6
OO
MUTE
STEREO
+6
OO
10
AUX
3-4
MTX2
MUTE
MTX3
STEREO
MTX4
AUX
AUX
0
1
AUX
0
2
AUX
0
3
AUX
0
4
AUX
0
5
AUX
0
6
AUX
0
7
0
8
AUX
AUX
9-10
0
9-10
STEREO
OO
+10
OO
+10
OO
+10
OO
+10
OO
+10
OO
+10
OO
+10
OO
+10
AFL
AFL
AFL
AFL
AFL
AFL
AFL
AFL
REV
REV
REV
REV
REV
REV
REV
REV
GRP1
TO M
GRP2
TO M
GRP3
TO M
GRP4
TO M
GRP5
TO M
GRP6
TO M
GRP7
TO M
GRP8
TO M
GRP1
TO LR
GRP2
TO LR
GRP3
TO LR
GRP4
TO LR
GRP5
TO LR
GRP6
TO LR
GRP7
TO LR
GRP8
TO LR
OO
MUTE
MONITOR
+10
MUTE GROUPS
REV
ROTARIES
=
=
PAN
L
R
L
R
L
10
L
R
L
10
R
10
L
R
MUTE
PK!
+6
0
SIG
PK!
+6
0
SIG
MUTE
AFL
GRP8
L
AUX8
10
10
AUX9-10
M
R
10
5
5
5
5
5
5
5
5
5
5
5
0
0
0
0
0
0
0
0
0
0
5
5
5
5
5
5
5
5
5
5
5
10
10
10
10
10
10
10
10
10
10
10
20
20
20
20
20
20
20
20
20
20
20
30
30
30
30
30
30
30
30
30
30
30
00
00
00
00
00
00
00
00
00
00
00
2
3
4
5
6
7
8
L
LISTEN
10
0
1
WEDGE
MODE
M
P/AFL
0dB
MUTE
AFL
AUX7
10
OO
PK!
+6
0
SIG
PK!
+6
0
SIG
GRP7
AUX6
L-R TO M
=
R
AFL
GRP6
AUX5
10
L
MUTE
AFL
GRP5
FOH
MONITOR
FADERS
PAN
PK!
+6
0
SIG
MUTE
AFL
AUX4
=
PAN
PK!
+6
0
SIG
MUTE
GRP4
AUX3
=
PAN
PK!
+6
0
SIG
AFL
GRP3
AUX2
10
R
MUTE
AFL
GRP2
=
PAN
PK!
+6
0
SIG
MUTE
AFL
AUX1
10
R
PK!
+6
0
SIG
MUTE
GRP1
=
PAN
L
PK!
+6
0
SIG
PK!
+6
0
SIG
40
=
PAN
PAN
AUX MODE
R
M
GL2800 User Guide
USO RESTRITO
Cue Sheet 2 of 3
GL2800
Copy and use this page to record your console settings.
+48V
+48V
+48V
+48V
+48V
+48V
+48V
+48V
POLARITY
POLARITY
POLARITY
POLARITY
POLARITY
POLARITY
POLARITY
POLARITY
LINE
LINE
(PAD)
0
20
30
0
40
GAIN
50
-14
6
LINE
(PAD)
60 40
20
30
50
-14
6
60 40
20
30
6
60 40
20
30
6
60 40
20
30
6
60 40
20
30
6
60 40
20
-14
6
12k
-15
1k
700
HM
12k
3k +15
4k
6k
500Hz
15k
-15
1k
700
HM
12k
3k +15
4k
-15
1k
6k
500Hz
15k
700
HM
12k
3k +15
4k
-15
1k
6k
500Hz
15k
700
HM
-15
1k
6k
500Hz
15k
700
HM
-15
1k
6k
500Hz
15k
3k +15
4k
700
HM
6k
500Hz
70
250
70
400
45
LM
-15
+15
35Hz
1k
-15
+15
180
250
70
400
45
LM
-15
+15
35Hz
1k
-15
+15
180
250
70
400
45
LM
-15
+15
35Hz
1k
-15
+15
180
250
70
400
45
LM
-15
+15
35Hz
1k
-15
+15
250
70
400
45
LM
-15
+15
180
35Hz
1k
80Hz
LF
80Hz
-15
+15
80Hz
-15
+15
EQ IN
AUX
+6
OO
AUX
-15
+15
+6
OO
180
250
HF
HF
12k
12k
+15
1k
-15
+15
+15
+6
OO
AUX
+6
OO
AUX
4
+6
OO
+6
OO
5
AUX
AUX
6
+6
OO
AUX
+6
OO
+6
OO
AUX
+6
OO
+6
OO
+6
OO
AUX
9-10
OO
+6
=
PAN
OO
+6
=
R
L
R
R
EVEN
PK!
+6
0
SIG
M
PAN
L
R
POST
PRE
L
R
EVEN
L
ODD
OO
R
L
R
EVEN
OO
R
+6
=
STEREO
OO
L
R
L
R
POST
PRE
POST
PRE
=
=
BAL
R
EVEN
L
ODD
+6
=
BAL
=
R
EVEN
POST
PRE
9-10
STEREO
POST
PRE
PAN
L
ODD
+6
AUX
BAL
=
PAN
L
ODD
+6
=
OO
POST
PRE
9-10
STEREO
POST
PRE
=
PAN
+6
OO
AUX
PAN
POST
PRE
=
R
EVEN
+6
=
+6
8
BAL
L
ODD
R
EVEN
L
ODD
R
EVEN
MUTE
MUTE
MUTE
MUTE
MUTE
MUTE
PFL
PFL
PFL
PFL
PFL
PFL
PFL
PFL
10
5
PK!
+6
0
SIG
M
10
5
L-R
1-2
5-6
30
M2
30
00
M4
GL2800 User Guide
M3
M4
30
M3
M4
7-8
M1
30
M2
00
M3
M4
M1
30
M3
M4
M1
30
M2
00
M3
M4
10
5-6
M1
M3
M4
10
7-8
20
30
20
M1
30
M2
M2
00
5
3-4
7-8
20
5
0
5
5-6
10
1-2
3-4
10
M
L-R
1-2
7-8
M2
00
5-6
5
PK!
+6
0
SIG
0
5
20
20
M
10
L-R
3-4
10
PK!
+6
0
SIG
0
5
5-6
5
1-2
3-4
10
M
10
L-R
1-2
7-8
M2
00
5-6
5
PK!
+6
0
SIG
0
5
20
M1
M
10
L-R
3-4
10
PK!
+6
0
SIG
0
5
5-6
5
1-2
7-8
M2
M
10
L-R
3-4
10
PK!
+6
0
SIG
0
20
M1
5
1-2
7-8
20
10
L-R
3-4
7-8
M
5
5
10
PK!
+6
0
SIG
0
1-2
3-4
M3
R
OO
OO
AUX
POST
PRE
9-10
STEREO
+6
MUTE
0
M1
L
PAN
L
ODD
+6
=
+6
7
MUTE
L-R
5-6
OO
OO
AUX
OO
+6
AUX
9-10
STEREO
PAN
=
PAN
L
ODD
+6
=
POST
PRE
=
PAN
AUX
+6
8
OO
+6
6
AUX
POST
PRE
OO
AUX
OO
+6
OO
+6
OO
5
7
8
POST
PRE
+6
AUX
AUX
POST
PRE
9-10
OO
PAN
POST
PRE
+6
OO
AUX
STEREO
+6
OO
8
+6
AUX
OO
+6
OO
OO
POST
PRE
6
7
AUX
POST
PRE
9-10
STEREO
PAN
L
+6
OO
AUX
9-10
STEREO
+6
OO
+6
AUX
AUX
7
8
POST
PRE
+6
OO
AUX
AUX
8
POST
PRE
AUX
+6
OO
AUX
8
+6
OO
7
+6
4
5
6
OO
AUX
OO
+6
OO
AUX
6
AUX
7
AUX
8
+6
OO
AUX
7
AUX
6
+6
AUX
5
+6
3
POST
PRE
+6
OO
OO
AUX
OO
+6
AUX
5
+6
OO
AUX
6
AUX
7
5
+6
OO
AUX
6
AUX
+6
4
OO
+6
2
AUX
POST
PRE
OO
AUX
OO
+6
OO
+6
OO
POST
PRE
AUX
5
+6
OO
+6
OO
POST
PRE
AUX
5
+6
OO
+6
OO
1
3
4
+15
EQ IN
+6
AUX
AUX
4
-15
AUX
OO
PRE-EQ
+6
OO
AUX
4
POST
PRE
AUX
+6
OO
AUX
4
POST
PRE
AUX
+6
OO
AUX
4
+15
2
3
+15
EQ IN
AUX
AUX
3
-15
80Hz
-15
+6
OO
PRE-EQ
AUX
+15
LF
1
2
PRE-EQ
3
+15
AUX
AUX
2
AUX
3
+6
-15
250Hz
-15
LF
+15
1
OO
+15
LM
EQ IN
AUX
AUX
PRE-EQ
AUX
3
+6
OO
-15
2k5
-15
LM
80Hz
-15
EQ IN
1
2
PRE-EQ
AUX
3
+15
16
HM
2k5
400
35Hz
LF
5
OO
+15
80Hz
-15
AUX
AUX
2
PRE-EQ
AUX
+6
AUX
2
+15
EQ IN
1
OO
LF
80Hz
-15
AUX
1
AUX
2
+15
EQ IN
AUX
1
LF
80Hz
-15
EQ IN
AUX
1
LF
0
-30
16
OO
250Hz
LF
100Hz
-5
15k
45
LM
60 40
HPF
-20
5
-30
-15
180
6
GAIN-10
0
HM
-15
40
50
-14
STEREO
-5
-20
3k +15
4k
30
100Hz
STEREO
12k
3k +15
4k
60 40
20
GAIN
HPF
100Hz
HF
(PAD)
0
40
50
GAIN-10
12k
30
GAIN
HPF
100Hz
HF
0
40
50
-14
LINE
(PAD)
GAIN
HPF
100Hz
HF
0
40
50
-14
LINE
(PAD)
GAIN
HPF
100Hz
HF
0
40
50
-14
LINE
(PAD)
GAIN
HPF
100Hz
HF
0
40
50
-14
LINE
(PAD)
GAIN
HPF
100Hz
HF
0
40
GAIN
HPF
LINE
(PAD)
00
M3
00
M4
41
Cue Sheet 3 of 3
GL2800
Copy and use this page to record your console settings.
+48V
+48V
+48V
+48V
+48V
+48V
+48V
+48V
POLARITY
POLARITY
POLARITY
POLARITY
POLARITY
POLARITY
POLARITY
POLARITY
LINE
LINE
(PAD)
0
20
30
0
40
GAIN
50
-14
6
60 40
20
30
6
60 40
USO RESTRITO
6k
500Hz
-15
70
15k
180
LM
HM
-15
+15
6k
500Hz
-15
70
400
1k
80Hz
15k
180
LM
1k
-15
+15
LF
+6
AUX
5
AUX
AUX
6
+6
OO
AUX
+6
OO
+6
OO
+6
OO
AUX
8
+6
AUX
+6
OO
OO
+6
=
PAN
OO
+6
=
R
L
R
M
R
EVEN
PAN
L
R
POST
PRE
L
L
ODD
R
R
EVEN
L
L
ODD
R
EVEN
+6
OO
OO
+6
POST
PRE
9-10
STEREO
OO
R
POST
PRE
AUX
+6
=
STEREO
OO
L
R
L
R
POST
PRE
POST
PRE
=
=
PAN
L
ODD
+6
=
PAN
=
R
EVEN
+6
8
POST
PRE
PAN
L
ODD
OO
AUX
PAN
=
PAN
+6
OO
9-10
+6
=
+6
7
AUX
OO
OO
AUX
POST
PRE
POST
PRE
=
PAN
+6
8
STEREO
+6
6
AUX
PAN
POST
PRE
=
R
EVEN
+6
=
OO
AUX
R
EVEN
PAN
L
ODD
R
EVEN
L
ODD
R
EVEN
MUTE
MUTE
MUTE
MUTE
MUTE
PFL
PFL
PFL
PFL
PFL
PFL
PFL
PFL
10
5
PK!
+6
0
SIG
M
10
5
L-R
7-8
20
30
M2
30
M3
M4
7-8
20
M1
30
M2
00
M3
M4
30
M3
M4
7-8
20
M1
30
M2
00
M3
M4
30
M3
M4
10
0
5
5-6
M1
20
M1
30
M3
M4
10
7-8
20
M2
00
5
3-4
7-8
M2
00
5-6
10
1-2
5
20
M1
M
L-R
3-4
10
PK!
+6
0
SIG
0
5
5-6
5
1-2
3-4
10
M
10
L-R
1-2
7-8
M2
00
5-6
5
PK!
+6
0
SIG
0
5
20
M1
M
10
L-R
3-4
10
PK!
+6
0
SIG
0
5
5-6
5
1-2
3-4
10
M
10
L-R
1-2
7-8
M2
00
5-6
5
PK!
+6
0
SIG
0
5
20
M1
M
10
L-R
3-4
10
PK!
+6
0
SIG
0
5
5-6
5
1-2
3-4
7-8
M
10
L-R
1-2
10
PK!
+6
0
SIG
0
5
42
R
OO
5
+6
OO
+6
POST
PRE
AUX
OO
+6
9-10
STEREO
+6
MUTE
3-4
M4
+6
=
OO
POST
PRE
MUTE
1-2
M3
L
PAN
L
ODD
0
M1
OO
+6
MUTE
L-R
5-6
9-10
STEREO
PAN
=
PAN
L
ODD
+6
=
POST
PRE
=
PAN
PK!
+6
0
SIG
OO
+6
4
7
AUX
OO
AUX
AUX
OO
PRE-EQ
+6
OO
+6
POST
PRE
AUX
9-10
STEREO
+6
OO
POST
PRE
AUX
PAN
POST
PRE
+6
OO
+6
OO
3
6
OO
+15
EQ IN
AUX
AUX
8
-15
2
5
AUX
8
POST
PRE
9-10
STEREO
PAN
L
+6
OO
+6
OO
AUX
8
AUX
9-10
STEREO
+6
OO
AUX
POST
PRE
AUX
9-10
+6
OO
+15
AUX
OO
+6
OO
-15
LF
1
AUX
7
400
PRE-EQ
+6
AUX
LM
+6
OO
POST
PRE
+6
OO
7
250
1k
AUX
4
6
+15
35Hz
+15
AUX
OO
180
45
EQ IN
+6
AUX
AUX
7
8
POST
PRE
+6
OO
AUX
AUX
8
OO
+6
OO
7
-15
3
OO
15k
80Hz
AUX
5
6
+15
2
OO
+6
AUX
6
AUX
7
AUX
AUX
-15
AUX
AUX
OO
-15
LF
6k
70
400
1k
3k +15
4k
500Hz
250
PRE-EQ
+6
5
LM
-15
1k
700
+15
35Hz
+6
POST
PRE
+6
OO
180
1
4
60 40
100Hz
HM
AUX
AUX
AUX
70
15k
45
+15
OO
+6
OO
500Hz
EQ IN
3
OO
+6
5
-15
AUX
4
6k
80Hz
2
POST
PRE
+6
+15
6
HPF
3k +15
4k
700
-15
AUX
AUX
OO
-15
LF
PRE-EQ
+6
AUX
6
AUX
7
+6
LM
50
-14
12k
-15
1k
400
1k
40
HF
250
35Hz
+6
3
60 40
30
100Hz
+15
1
OO
6
20
GAIN
HPF
HM
AUX
AUX
OO
180
45
+15
2
4
70
15k
EQ IN
AUX
AUX
AUX
6
-15
PRE-EQ
+6
500Hz
80Hz
+6
OO
3
OO
+15
6k
-15
1
AUX
5
-15
LF
-14
3k +15
4k
700
400
AUX
POST
PRE
+6
OO
LM
50
12k
-15
1k
HM
(PAD)
0
40
HF
250
1k
30
100Hz
+15
35Hz
+15
PRE-EQ
OO
180
45
EQ IN
2
AUX
5
+6
OO
-15
AUX
POST
PRE
15k
80Hz
+6
OO
500Hz
-15
1
OO
+6
AUX
+15
6k
70
400
-15
LF
HM
AUX
4
OO
LM
60 40
20
GAIN
HPF
3k +15
4k
700
250
1k
6
12k
+15
35Hz
+15
AUX
POST
PRE
180
45
EQ IN
+6
OO
+6
AUX
-15
3
4
70
15k
0
40
50
-14
LINE
(PAD)
HF
-15
80Hz
AUX
AUX
OO
+15
PRE-EQ
+6
OO
4
-15
LF
500Hz
30
100Hz
1k
6k
-15
2
3
AUX
LM
60 40
12k
250
1k
6
20
GAIN
HPF
3k +15
4k
700
400
0
40
50
-14
LINE
(PAD)
HF
+15
35Hz
30
100Hz
HM
AUX
AUX
3
180
45
+6
PRE-EQ
AUX
70
15k
1
2
60 40
20
GAIN
HPF
-15
AUX
AUX
2
500Hz
+15
OO
6
1k
6k
EQ IN
1
OO
700
-15
AUX
-14
3k +15
4k
80Hz
-15
50
12k
-15
1k
400
0
40
HF
250
35Hz
+15
1
60 40
30
100Hz
+15
45
EQ IN
AUX
6
20
LINE
(PAD)
GAIN
HPF
HM
80Hz
-15
-14
3k +15
4k
700
250
35Hz
LF
1k
+15
45
50
12k
-15
3k +15
4k
700
0
40
HF
12k
-15
1k
30
100Hz
HF
12k
20
LINE
(PAD)
GAIN
HPF
100Hz
HF
0
40
50
-14
LINE
(PAD)
GAIN
HPF
HM
LINE
(PAD)
30
M2
00
M3
00
M4
GL2800 User Guide
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