Allen & Heath AH-GL2400-24 User manual

ALLEN&HEATH

GL2400

USER GUIDE

Publication AP5597

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.

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.

GL2400 User Guide AP5597 Issue 2

Copyright © 2005 Allen & Heath Limited. All rights reserved

Allen & Heath Limited

Kernick Industrial Estate, Penryn, Cornwall, TR10 9LU, UK
http://www.allen-heath.com

2 GL2400 User Guide

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 with its underside

cover 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 to rain or moisture or use it in damp or wet
conditions. Do not place containers of liquids on it which might spill into
any openings.

Ventilation: Do not obstruct the rear and top 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.

GL2400 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 becomes wet, switch
off and remove mains power immediately. Allow to dry out thoroughly
before using again.

Cleaning 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

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.

WIRE COLOUR

4 GL2400 User Guide

Introduction

Welcome to the Allen & Heath GL2400, 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

Gain Structure.................................................. 23

Using the Oscillator / Noise Generator ........... 24

Mixing with Faders or Gain Controls............... 24

Using PFL / AFL ............................................... 25

The dB.............................................................. 25

Using Inserts ....................................................25

Polarity ............................................................. 26

Mixing the PA in Mono or Stereo? .................. 26

Zero the console .............................................. 26

Turning the System On or Off ......................... 26

Sound Levels ...................................................26

Dual Functionality ............................................27

Applications for the Matrix............................... 28

Create IEM Mixes with Ambience ................... 29

Using the Matrix to Create a Recording.......... 29

Recording with the GL2400............................. 29

Pre/Post Fade Aux Settings ............................ 29

Aux-Fed Subs .................................................. 30

Creating a Separate C Mix .............................. 30

Other M Output Applications........................... 30

Using the Channel Direct Outputs .................. 31

Using the Stereo Channels ............................. 31

A Note about Combining Signals ................... 31

Contents

Warranty................................................. 2

Important Safety Instructions ................3

General Precautions ..............................4

Introduction to this Guide...................... 5

Panel Layouts ........................................ 6

Introducing the GL2400....................8

Installing the Console ..........................10

Connecting Power ...............................11

Audio Connections ..............................13

The Console Connectors ....................14

Mono Input Channel ............................16

Stereo Input Channel........................... 18

Group/Aux Masters.............................. 19

Aux5-6, LRM Masters........................... 20

7x4 Matrix............................................. 21

Monitor, Talkback and Sig Gen ..........22

Applications and Operating Tips.........23

Specifications ......................................32

System Block Diagram ........................34

User Options........................................35

Cue Sheet ............................................38

GL2400 User Guide 5

+48V

POLARITY

LINE LINE

(PAD) (PAD)

0

30

40

20

GAIN

50

6-14 4060 6-14 4060

HPF

100Hz

HF

12k

-15

+15

3k

1k

4k

700

6k

500Hz

15k

HM

+15

-15
180

70

250

45

400

35Hz

1k

LM

-15

+15

LF

80Hz

-15

+15

EQ IN

AUX

1

OO +6

AUX

2

OO +6

AUX

3

OO +6

AUX

4

OO +6

POST
PRE

AUX

5

OO +6

AUX

6

+6OO

POST
PRE

=

PAN

L

R

ODD

EVEN

MUTE

+48V

POLARITY

0

30

40

20

GAIN

50

HPF

100Hz

HF

12k

-15

+15

3k

1k

4k

700

6k

500Hz

15k

HM

+15

-15
180

70

250

45

400

35Hz

1k

LM

-15

+15

LF

80Hz

-15

+15

EQ IN

AUX

1

OO +6

AUX

2

OO +6

AUX

3

OO +6

AUX

4

OO +6

POST
PRE

AUX

5

OO +6

AUX

6

+6OO

POST
PRE

=

PAN

L

R

ODD

EVEN

MUTE

+48V

30

40

20

MIC

GAIN

6

60

0

-5

ST1

-10

-20

O

O

16

STEREO

CH15

LR

0

-5

ST2

-10

-20

O

O

16

STEREO

CH15 CH16

LR

HF

12k

-15

+15

HM

2k5

-15

+15

LM

250Hz

-15

+15

LF

80Hz

-15

+15

EQ IN

AUX

1

OO +6

AUX

2

OO +6

AUX

3

OO +6

AUX

4

OO +6

POST
PRE

AUX

5

OO +6

AUX

6

+6OO

POST
PRE

=

BAL

L

ODD

EVEN

MUTE

+48V

30

40

20

MIC

GAIN

50

5

10

5

10

R

ST3

STEREO

ST4

STEREO

250Hz

80Hz

HF

12k

HM

2k5

LM

LF

AUX

1

AUX

2

AUX

3

AUX

4

AUX

5

AUX

6

BAL

-10

-20

-10

-20

6

-5

O

O

-5

O

O

-15

-15

-15

-15

OO +6

OO +6

OO +6

OO +6

OO +6

L

ODD

50

60

0

16

CH16

LR

0

16

LR

+15

+15

+15

+15

EQ IN

POST
PRE

+6OO

POST
PRE

=

EVEN

MUTE

EXT

EXT

EXT

IN IN

5

10

5

10

GRP

GRP

GRP

GRP

LEVEL

OO

O+6

O +6

GRP

1

1

OO

O

+6

O +6

GRP

2

2

OO

O

+6

O +6

GRP

3

3

OO

O

+6

O +6

GRP

4

4

OO

O

+6

L

OO

R

OO

O +6

L

O+6

O +6

R

OO

O

+6

O +6

LEVEL

O

+6

O +6

MUTE

MUTE

AFL AFL

AUX

2

PAN

PK!

+6

0

SIG

OO+10 +10

AFL

REV

GRP2GRP1
TO LR

=

AUX

+6

SIG

AUX

0 0

1

OO

AFL

REV

TO LR

PAN

L R=L R

PK!

+6

0
SIG

R

MUTE MUTE

AFLAFL

IN

O

O +6

GRP

1

O

O +6

GRP

2

O

O +6

GRP

3

O

O +6

GRP

4

O

O +6

L

O

O +6

R

O

O +6

LEVEL

OO +6

3

OO +10 OO

REV

PAN

PK!

0

MUTE

AFL

0

AFL

EXT

IN

O

O +6

GRP

1

O

O +6

GRP

2

O

O +6

GRP

3

O

O +6

GRP

4

O

O +6

L

O

O +6

R

O

O +6

LEVEL

OO +6

AUX

4

REV REV

GRP4GRP3
TO LRTO LR

=

PAN

PK!

+6

0

SIG

TALKBACK

MIN MAX

OSC/NOISE

MINLMAX

1kHz
PINK

ON

SELECT

L-R

GRP
1-4

AUX
1-2

AUX
3-4

AUX
5-6

MUTE

TALK

AFL

AUX

0

5

+10

OO +10 OO

AFL

RL R=L

PK!
+6

0

SIG

MUTEMUTE MUTE

MIC

PHONES

2TRK REPLAY

OO

+10

2TRK
TO LR

R

+16

+9
+6
+3

0

-3

-6

-9

-12

-16

-20

-30

PFL

POWER

AFL

MONITOR

0

10

L-R
2TRK

AUX

0

0

6

+10

AFL

AFL

REV

MODE

FOH
MONITOR

LISTEN WEDGE

M SOURCE

MONO (L+R)
AUX 6

(AUX FED SUB)

PK!

PK!

+6

+6

0

SIG

AFLAFLAFL

0

SIG

MUTE

AFL

AFL

6 GL2400 User Guide

G

The Range:

GL2400-16 14 mono mic/line, 2 mic/dual stereo

GL2400-24 22 mono mic/line, 2 mic/dual stereo

GL2400-32 30 mono mic/line, 2 mic/dual stereo

GL2400-40 38 mono mic/line, 2 mic/dual stereo

RPS11 External power supply for the GL2400-40

MPS12 Backup power supply for the 16,24,32 frame sizes

GL2400-SLV2 Sys-Link V2 console in/out expander option kit

LAMP

2TRK IN

2TRK OUT

LISTEN WEDGE AUX 6 AUX 5 AUX 4 AUX 3 AUX 2 AUX 1

OUT

M OUT R OUT L GRP 4 GRP 3 GRP 2 GRP 1

MONITOR

OUT

MATRIX

EXT

EXT

IN IN IN IN

MTX

4

INSERTLINSERT4INSERT3INSERT2INSERT1INSERT

L/MR

R

AUX5AUX4AUX3AUX2AUX1AUX

6

LR

R L GRP 4GRP 3GRP 2GRP 1

EXT

3421

MTX

MTX

3

2

MATRIX EXT IN

LR

IN1

IN2

IN3

IN4

EXT

MTX

1

LAMP

ENGINEERED IN ENGLAND BY ALLEN & HEATH LIMITED

MIC OUT

ST4 ST3 ST2 ST1

L/M

R

GRP/AUX REVERSE

L/M

R

(BREAKPOINT)

MIC OUT

1516

L/MRL/M

R

MIC INMIC IN

1516

USE ONLY THE RECOMMENDED A&H BACKUP POWER SUPPLY

DIRECT

OUT

7

INSERT

7654321

EXT DC IN

DIRECT

OUT

INSERT

6

DIRECT

OUT

INSERT

LINE IN

14

MIC IN

EXT INT

DIRECT

14

14 13 12 11 10 9 8

OUT

13

INSERT

LINE IN

LINE INLINE IN

13

MIC IN

AVIS: RISQUE DE CHOC ELECTRIQUE - NE PAS OUVRIR.
WARNING: TO REDUCE THE RISK OF ELECTRIC S HOCK
DO NOT EXPOSE THIS APPARATUS TO RAIN OR MOISTURE.
THIS APPARATUS MUST BE EARTHED BY THE POWER CORD.

ACTIVE POWER SUPPLY

DIRECT

OUT

5

INSERT

DIRECT

OUT

12

INSERT

LINE IN

12

MIC IN MIC IN MIC IN MIC IN MIC IN

CAUTION

RISK OF ELECTRIC SHOCK

DO NOT OPEN

SERIAL NUMBER

DIRECT

OUT

4

INSERT

DIRECT

OUT

11

INSERT

LINE IN

11

CAUTION: FOR CONTINUED PROTECTION AGAINST RISK OF FIRE REPLACE FUSE WITH SAME TYPE AND RATIN
ATTENTION: REMPLACER LE FUSIBLE AVEC UN DES MEMES CARACTERISTIQUES.

DIRECT

OUT

3

INSERT

ON/OFF

I

0

DIRECT

OUT

INSERT

DIRECT

OUT
10

INSERT

LINE IN

10

100 - 240 V AC ~ 47- 63 Hz 90W MAX

2

MAINS INPUT

DIRECT

INSERT

OUT

DIRECT

OUT

INSERT

LINE IN

9

1

DIRECT

9

OUT

INSERT

LINE IN

LINE INLINE INLINE INLINE INLINE IN

8

8

FUSE

T1.6A L 250V 20MM

LINE IN

7

MIC IN MIC IN MIC IN MIC IN MIC IN MIC IN MIC IN

LINE IN

6

LINE IN

5

OUTPUT INPUT

LINE IN

4

SYS-LINK V2 CONSOLE EXPANDER ( option )

LINE IN

3

LINE IN

2

LINE IN

LINE INLINE INLINE INLINE INLINE INLINE INLINE IN

GL2400 User Guide 7

1

Introducing the Allen & Heath GL2400

The GL2400 is a 4-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
GL2400 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 GL2200 and provided yet
more innovative capability and enhanced performance for modern mixing.

• 16, 24, 32, 40 channel frames

• LR main mix

• Multi- mode M output

• 4 Group sends

• 6 Aux sends

• 7x4 Matrix

• Proper dual functionality for FOH/Monitor mixing

• Recording capable

• M can be configured as LR sum, C mix, Wedge, or Aux-Fed Sub master

• Sub grouping with pan control

• Matrix external inputs with level trims and common input capability

• 2 stereo channels each with mic and dual stereo line inputs

• Stereo channel mic input can cross patch into matrix for ambience feed

• Stereo channel line inputs can be assigned independently to LR

• Responsive 4 band, 2 sweep EQ

• 100Hz channel high pass filters

• Individual phantom power

• Polarity switching

• Channel and master meters

• Channel direct outputs

• Per channel pre/post fader aux switching

• Internal jumper plugs for pre/post-EQ aux, direct out and other options

• Mutes on all fader masters

• 100mm dust protected faders

• Assignable talkback

• 1kHz oscillator / pink noise generator

• 2-Track monitoring and replay to LR

• Headphones and local monitor outputs

• Dedicated stereo monitor meters

• Electronically balanced XLR outputs with +26dBu drive capability

• Preamp +34dBu maximum input capability for mic or line

• Ultra low noise mix head amp design

• Internal power supply with redundant backup supply input

• 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 lamp sockets

8 GL2400 User Guide

Here are just a few key points we considered when specifying the GL2400:

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 GL2400 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 console power supply has a wide input range, plenty of overhead
and even includes a backup supply capability for added security.

Performance The GL2400 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 GL2400 takes this an important stage
further. Tamperproof recessed switches configure the console safely for optimum FOH or
stage monitor operation, or for mixing monitors from FOH. In FOH mode you even get a
fader controlled XLR ‘M’ output which can be configured to drive a mono PA or fill, or to
work with an aux to create a ‘C’ mix within an LCR system, or as a convenient master
control when using the increasingly popular ‘aux-fed-subs’ technique. In MONITOR mode
the ‘M’ fader becomes the engineer’s monitor wedge control, you get all six aux masters
available on faders with mutes, inserts, meters and electronically balanced XLR drive, and
you still get the 4 subgroups to LR, and the groups/LR feeding the matrix. Unique at this
price point we have added a 7x4 matrix to give you even greater mixing capability. 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 yet more monitor outputs easily
created from the groups and LR with added ambience for the in-ear application. This
compact console can feed up to 10 independent mixes, for example 6 wedges and 4 mono
or 2 stereo IEM. We have also considered the RECORDING application with direct outputs
on all mono channels, 4 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 strips with patchable mic pre’s and dual assignable stereo inputs, the host
of internal pluggable jumper options, Sys-Link V2 console expansion… and much more.
We hope you enjoy being as creative using the GL2400 as our team enjoyed creating it.

Carey Davies, Head of Design, and sound guy too…

GL2400 User Guide 9

Installing the Console

The GL2400 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.

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 ventilation openings on the top and rear surfaces. Ensure
adequate air flow around these surfaces. To avoid audible hum, buzz or other
performance degradation, do not place equipment that radiates strong
electromagnetic fields such as mains power supplies, amplifiers and computers next
to or directly underneath the console.

5

149

6

GL2400-416 = 609

GL2400-424 = 817

GL2400-432 = 1025

GL2400-440 = 1233

GL2400-416 = 14 MONO / 2 STEREO INPUTS

GL2400-424 = 14 MONO / 2 STEREO INPUTS

GL2400-432 = 14 MONO / 2 STEREO INPUTS

GL2400-440 = 22 MONO / 2 STEREO INPUTS

5

4

553

MASTER

SECTION

7

7

7

57

63

21

GL2400-424 = 8 MONO INPUTS

GL2400-432 = 16 MONO INPUTS

GL2400-440 = 16 MONO INPUTS

560

10 GL2400 User Guide

Connecting Power

MAINS INPUT

100 - 240 V AC ~ 47- 63 Hz 90W MAX

FUSE

T1.6A L 250V 20MM

EXT DC IN

EXT INT

USE ONLY THE RECOMMENDED A&H BACKUP POWER SUPPLY

ACTIVE POWER SUPP LY

RISK OF ELECTRIC SHOCK

AVIS: RISQUE DE CHOC ELECTRIQUE - NE PAS OUVRIR.
WARNING: TO REDUCE THE RISK OF ELECTRIC SHOCK
DO NOT EXPOSE THIS APPARATUS TO RAIN OR MOISTURE.
THIS APPARATUS MUST BE EARTHED BY THE POWER CORD.

CAUTION

DO NOT OPEN

SERIAL NUMBER

ON/OFF

I

0

CAUTION: FOR CONTINUED PROTECTION AGAINST RISK OF FIRE REPLACE FUSE WITH SAME TYPE AND RATING.
ATTENTION: REMPLACER LE FUSIBLE AVEC UN DES MEMES CARACTERISTIQUES.

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 the console power supply
mains voltage input is the same as your local supply. Check that the correct mains lead
with moulded plug has been provided with your console. Make sure that the IEC mains
plug is pressed fully into the panel socket 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.

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.

To turn the console on, press the ON/OFF switch next to the IEC mains input socket. To
turn the console off, press this switch again.

Connecting a backup supply

A socket 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 stop
working. The recommended backup supply for the GL2400 16, 24 and 32 models is the
Allen & Heath MPS12 power unit. The recommended backup supply for the 40 channel
model is the Allen & Heath RPS11 power unit.

Only plug the recommended Allen & Heath power unit into this socket. 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.

The console can work with just the internal supply powered by mains, or just the backup
supply, or with both powered at the same time. To ensure uninterrupted performance in
the unlikely event of a failure, we recommended that both supplies are powered.

GL2400 User Guide 11

XLR male socket XLR female socket

INPUTOUTPUT

1+3 = 12V

3

Female XLR plug

PIN 2 = HOT

BALANCED

UNBALANCED

INPUT / OUTPUT

UNBALANCED

link Ring to Sleeve

BALANCED

1=ground

Sleeve=ground

Ring=cold -

3=cold -

Tip=hot +

2=hot +

21

12

1

4 = 0V

LAMP

3

3

2=hot +

3=cold -

1=ground

BALANCED

XLR male plug

UNBALANCED

HEADPHONES

Sleeve=ground

Ring=RIGHT

Tip=LEFT

SYS-LINK V2 OPTION

SYS-LINK II OUTPUT OPTION

14 GRP 3+

15 GRP 2+

16 GRP 1+

17 R+

18 L+

19 0V (CHS)

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)

UNBALANCED

INSERT

Sleeve=ground

Ring=return

Tip=send

L- 37

R- 36

AUX 1- 31

AUX 4- 28

AUX 5- 27

AUX 2- 30

GRP 3- 33

GRP 2- 34

GRP 1- 35

GRP 4- 32

AUX 3- 29

AUX 6- 26

PFL- 25

nc 21

nc 23

nc 20

nc 22

AFL- 24

12 GL2400 User Guide

Audio Connections

The GL2400 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 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
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.

output provides similar interference rejection, but not as much

GL2400 User Guide 13

RETURN

SEND

GROUND

The Console Connectors

MONO CHANNEL MIC / LINE IN The LINE (PAD) switch selects

DIRECT

OUT

24

INSERT

24

LINE IN

24

MIC IN

MIC OUT

16

ST4 ST3

L/M

R

L/M

MIC IN

16

INSERT

TIP

RING

LINK RING TO SLEEVE TO UNBALANCE

LAMP

R

RETURN

SEND

(BREAKPOINT)

SEND

RETURN

PROCESSOR

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
required. The MIC XLR can be switched to
provide +48V DC via 6k8 ohm resistors to
pins 2 and 3 for microphones such as
condensers which require phantom powering.

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 two independent stereo line inputs. The
balanced MIC input accepts a maximum +14dBu and can be switched to
provide 48V phantom power.

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.

STEREO CHANNEL LINE IN Stereo inputs ST1 and ST2 feed

channel 15, and ST3 and ST4 feed channel 16 respectively, or can be
routed directly to LR. These inputs use TRS jacks. ST1,3 are
unbalanced, ST2,4 are balanced. Unbalanced inputs automatically
connect the TRS ring to ground when working with balanced sources.
The L input is normalled through the R socket to accept mono signals on
a single jack.

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

OUT

and operate at 0dBu. The group (aux) and LR 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

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.

LAMP The 16 channel console has one, the larger models have 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.

INPUT

+IN

TIP +INTIP

RING -INRING

1

- IN

3

MIC

LINE

2

14 GL2400 User Guide

Operating Modes

In FOH mode, LR feeds the
main PA. M sums the L and R
post-fade signals to provide an
additional feed for a mono fill
speaker or zone, or a main feed
into a mono PA. Groups 1-4
may be used for multitrack
recording, zone feeds and so
on, or simply left unconnected
where they are used as
‘subgroups’ to LR for level
masters and/or inserted
processing.

In monitor mode
and LR XLRs and inserts
become the aux mix masters.
M becomes the engineer’s
listen wedge AFL/PFL feed.
This configures the console
with 6 main stage monitor and
an engineer’s output. The
groups and LR are still available
via the matrix to provide yet
more monitor feeds.

EXT

IN IN IN IN

MTX

4

EXT

3421

MTX

3

IN4

MONITOR

OUT

OUTPUT INPUT

Groups 1-4

EXT

MTX

2

MATRIX EXT IN

IN1

IN2

IN3

2TRK IN

2TRK OUT

SYS-LINK V2 CONSOLE EXPANDER ( option )

EXT

MTX

L/MR

LR

1

LR

AUX

AUX

AUX

AUX

AUX

6

5

4

3

LISTEN WEDGEAUX 6AUX 5 AUX 4AUX 3AUX 2AUX 1

OUT M OUT R OUT L GRP 4 GRP 3 GRP 2 GRP 1

R L GRP 4GRP 3GRP 2GRP 1

AUX

2

1

GRP/AUX REVERSE

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 +25dBu.
The L and R outputs typically feed the house PA system in live sound
mixing, or a 2-track recorder in studio mixing. In monitor mode, these
outputs reverse with the Aux TRS jack connections.

AUX OUT 1-6 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

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.

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 A blank plate is fitted here as standard.

The GL2400 Sys-Link V2 (version 2) input/output option kit is available
from Allen & Heath. Refer to OPTIONS later in this guide.

GL2400 User Guide 15

The MONO Input Channel

+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.

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.

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
normals through the TRS socket. With nothing plugged into the line
input the switch therefore becomes a PAD for the mic XLR
attenuates the input signal by 20dB for connection to high level
microphone or line sources. This gives the mic preamp a massive
74dB range and headroom of +34dB to deal with the hottest signals.

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.

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
to ‘0’ and mixing using the GAIN controls.

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.

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.

GAIN

HF

12k

HM

LM

LF

80Hz

AUX

1

AUX

2

AUX

3

AUX

4

AUX

5

AUX

6

PAN

0

700

500Hz

45

35Hz

ODD

30

20

6-14 4060

-15

1k

-15

70

-15

-15

OO +6

OO +6

OO +6

OO +6

OO +6

L

+48V

POLARITY

LINE

(PAD)

HPF

3k

180

EQ IN

=

100Hz

+15

+15

+15

+15

MUTE

40

50

4k

6k

15k

250

400

1k

POST
PRE

+6OO

POST
PRE

R

EVEN

input. The XLR

. It

recommend the practice of setting the faders

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.

16 GL2400 User Guide

LF / HF

HEADROOM

SIGNAL-TO-NOISE RATIO

HPF

HM

LM

CLIPPING

SIGNAL

DYNAMIC RANGE

NOISE

+5

0dB

-5

-10

-15

-20

-25

-30

-35

-40

+20

+15

+10

+5

0dB

-5

-10

-15

-20
20 50 100 200 500 1k 2k 5k 10k

+20

+15

+10

+5

0dB

-5

-10

-15

-20
20 50 100 200 500 1k 2k 5k 10k 20k

+20

+15

+10

+5

0dB

-5

-10

-15

-20

+20
+16
+12

+9
+6
+3
+1

0

-1

-3

-6

-9

-12

-16

-20

NORMAL OPERATING RANGE

-30

-40

-50

-60

-70

-80

-90

AUX SENDS These rotary controls adjust how much channel

signal is mixed to the aux outputs. Each of the 6 auxes has its own
control. They adjusts from fully off to +6dB boost. Unity gain 0dB is
marked at 3 o’clock position. Auxes 1-4, 5-6 are switched pre/post.
The settings may be changed if preferred by repositioning internal
jumper link options. They offer several different combinations of pre
and post-fade sends, and a post-EQ option for the pre-fade sends.
More detail is provided in OPTIONS later in this guide.

Pre-fade aux sends are not affected by the channel fader movements.

10k5k2k1k500200100502010

These are typically used to feed stage monitors. In most cases users
also prefer that the monitor sends are not affected by inserted
processors or the channel EQ. 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 ‘masters’ for all monitor
mixes. Pre or post-fade sends may also be used for special
applications such as recording, zone feeds, clean feeds and aux fed
subs or centre speaker.

PRE When pressed, the pre-fade channel signal is sent to the

associated auxes. When released, the post-fade signal is sent. Auxes
1 to 4 and 5, 6 are grouped for pre/post switching. Default setting is
pre-insert, pre-EQ so that inserted compressors and EQ do not affect
the sends when mixing monitors from FOH. You can change this by
repositioning the internal option jumpers.

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.

MUTE When pressed, the channel signal is turned off. This affects

the feed to the LR 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. The PFL switch yellow indicator
lights to show that PFL has been selected on that channel. Selecting
more than one PFL at the same time mixes those signals together in
the monitor.

METER A 4 LED channel meter displays the pre-fader signal level.

20k10k5k2k1k5002001005020

!

‘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.

ROUTING Press L-R to route the channel signal to the main LR

mix. Press 1-2 or 3-4 to route to the 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. You can route to L-R and all groups
simultaneously by pressing all switches. Check that you have set
these switches correctly before you start mixing.

FADER A high quality 100mm smooth travel fader with protective

dust cover controls the channel level feeding the main LR mix, groups
and post-fade aux sends. It also affects the direct output if this has
been set to post-fade using the internal option jumpers. The fader
provides +10dB maximum boost above its normal unity gain 0dB
position.

GL2400 User Guide 17

The STEREO Input Channel

MIC

GAIN

ST3

STEREO

ST4

STEREO

HM

LM

250Hz

80Hz

AUX

AUX

AUX

AUX

AUX

AUX

BAL

-20

-20

HF

12k

2k5

LF

1

2

3

4

5

6

20

-10

O

-5

-10

O

-15

-15

-15

-15

ODD

30

6

0

-5

O

0

O

OO +6

OO +6

OO +6

OO +6

OO +6

=

L

+48V

CH16

LR

CH16

LR

EQ IN

+15

+15

+15

+15

EVEN

MUTE

40

60

16

16

POST
PRE

+6OO

POST
PRE

Each GL2400 stereo channel features a mono microphone preamp
as well as two stereo line inputs. These three sources can be used

50

independently or mixed together into the channel, so providing a
unique flexibility. For example, you could configure a conventional

5

10

mono microphone channel with the two ‘short return’ stereos routed
direct to LR for effects. Alternatively 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 ST line

5

10

inputs mix two external stereo effects processor returns or sound
effects players via a single channel. This can be useful in saving
channels, letting you mix many inputs in a small space. Of course,
one stereo could feed the channel, the other route direct to LR. Two
stereo channels could be linked so that the mic preamps cross patch
to provide one stereo mic and one stereo line channel, with two ‘short
returns’ also available… See ‘Operating Tips’ later in this guide.

MIC INPUT Similar to the mono channel microphone preamplifier

without the line (pad) and polarity switches. Gain and 48V phantom
power switching are included. 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.

DUAL STEREO LINE INPUTS

Each stereo channel has two
stereo inputs which can be used separately, mixed together or split so
that one feeds the channel, the other routes direct to LR. ST1 and 2
feed channel 15 (23), ST3 and 4 feed channel 16 (24). 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. Each input has its own level control to adjust from fully off to
+16dB gain. Centre position is unity (0dB) gain.

Routing mode switch Recessed to prevent accidental

operation. In the normal up position the ST signal mixes into the
associated stereo channel. When pressed the signal is routed direct
to the LR mix instead of the channel.

EQ Similar to the mono channel, but the two peak/dip mid bands

are fixed at 250Hz and 2.5kHz centre frequencies.

R

AUX SENDS These work as described for the mono channel, but

the L and R sides of the stereo signal sum together to feed each aux in
mono. This can be changed using an internal jumper so that L feeds
the odd numbered auxes and R feeds even. The auxes can be
switched pre or post-fader but are always sourced post-EQ.

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.

MUTE When pressed, all the channel pre and post-fade signals are

turned off except the MIC OUT and any stereo 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.

METER As the mono channel, but the left and right signals are

summed to display in mono.

ROUTING As the mono channel, but routes the left signal to L and

odd groups, right signal to R and even groups.

FADER The stereo fader provides +10dB maximum boost above

its normal unity gain 0dB position

18 GL2400 User Guide

The GROUP / AUX Masters

PK!
+6

SIG

AUX

PAN

0

AUX MASTERS

Each aux mix has a master level control that
adjusts the output level to match external equipment, or trims the
monitor, effect or other send without affecting the mix balance. Up to

1

0

OO

+10

AFL

REV

+10dB boost is available above the normal 0dB position. Note that
this becomes the group or 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.

=

GRP1
TO LR

REV mode switch These switches reverse the function of the

L

R

MUTE

AFL

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 3, 4 giving you two fader
subgroups, two monitor sends on faders, and main LR mix.

Note: The groups always feed the matrix and the subgroup controls
(PAN and GRP TO LR) regardless of mode. This means the group mix
can still perform a useful function when the console is configured in
monitor mode.

PAN Positions the group signal between L and R in the stereo mix

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. The centre position (mono image) is
detented for quick resetting. Note that the group mix always feeds
these subgroup controls regardless of FOH or monitor mode selected.

METER A 4 LED bar meter displays the post-fade group signal

(FOH mode), or aux signal (monitor mode, REV pressed).

MUTE When pressed the group (aux) signal is turned off. This

affects the feed to the output XLR, LR and matrix. The red indicator
lights when the channel is muted.

GROUP AFL Press AFL to listen to the post-fade, pre-mute group

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.
The yellow indicator lights to show that AFL has been selected on that
master.

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.

GL2400 User Guide 19

The AUX 5-6, L-R-M Masters

AUX

5

OO +10 OO

REV

PK!
+6

0

SIG

AFL

AFL

MUTE

0

AUX

PK!
+6

0

SIG

6

M SOURCE

+10

AFL

REV

LISTEN WEDGE

MONO (L+R)
AUX 6

(AUX FED SUB)

MUTE

AFL

AUX 5 and 6 Masters These function in the same way as

0

MODE

FOH
MONITOR

described for auxes 1 to 4. In monitor mode

, the recessed REV switch
reverses the AUX5 master with L, and AUX6 with R. Here the aux
signals are presented to the L and R XLR outputs complete with their
inserts. The LR mix swaps on to the Aux TRS jack outputs. Note that
the LR mix always feeds the matrix and 2-track regardless of mode
selected.

LR Masters 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, an AFL switch and a MUTE switch so that
L and R can be separately monitored and muted. This is most useful
in monitor mode where these masters carry the AUX5 and AUX6

PK!
+6

0

SIG

AFL

signals.

M Master A 100mm fader adjusts the level of the signal to the M

output XLR. The master is fully featured and includes a 4 LED bar
meter, an AFL switch and a MUTE switch.

The M output adds a true touch of genius to the versatility of the
GL2400. The source is selected using two mode switches above
the R fader. These are recessed to prevent accidental operation. Use
a pen or pointed object to set the position.

FOH mode
panel), the post-fade L and R mix are summed together to provide a
mono source. Use this to feed a mono PA, fill, delay or zone speakers,
or even a mono broadcast or recording send.

– With both switches in the up position (flush with the

Monitor mode

- Press the upper switch to create an engineer’s
monitor listen wedge feed from the AFL/PFL mix. Note that in this
mode the M AFL switch is disabled. 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 GL2400 can be configured as a
compact yet fully featured monitor console.

Aux-Fed-Subs mode

– Press only the lower switch to configure M as
the master for AUX6. This innovative feature is ideal when driving your
sub bass speakers with their own mix fed from an aux, a technique
becoming more popular in FOH mixing. This mode provides all the
main PA masters (L, R and SUB) with faders, meters, MUTE and AFL.
Using the faders you can adjust the level of the main PA without losing
the balance between the tops and subs. The signal is not affected by
the AUX6 rotary master. However, the rotary output can still provide
another sub feed with its own independent master control.

Route all sources to LR in the usual way to feed the main ‘top’
speakers. In addition, route sources with low frequency content such
as kick drum, bass, keyboards, sound effects to the sub speakers by
turning up the AUX6 send rotary on those channels. Make sure all
channel aux 5-6 sends have been set for post-fader operation. Use
two crossovers, one for the stereo LR mid/top frequencies, the other
for the sub feed. Set the system up so that the correct balance
between tops and subs is achieved when the channel send is at its ‘0’
(3 o’clock) position and the L, R and M faders in line with each other.

Aux-Fed-Centre mode

– The same principle as above, but AUX6 is
used to feed a centre mix such as a fill or C in an LCR system. To
route to C only, turn up the channel AUX6 send to 3 0’clock unity
position, and turn off its assignment switch to LR.

20 GL2400 User Guide

7x4 MATRIX

EXT

IN

O

O +6

GRP

1

O

O +6

GRP

2

O

O +6

GRP

3

O

O +6

GRP

4

O

O +6

L

O

O +6

R

O

O +6

LEVEL

The matrix adds to the powerful multi-tasking capability of the
GL2400. 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 input. 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.

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

IN1

IN2

IN3

IN4

OO +6

MUTE

AFL

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 (2,3,4) Mixes in the post-fader, post-mute group mix. The

rotary provides +6dB boost.

L (R) 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 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.

AFL Press AFL to listen to the post-level matrix mix in the

headphones and local monitor without affecting the main outputs.
The console monitor meters are interrupted with the matrix signal.
The yellow indicator lights to show that AFL has been selected on that
master. Note that MUTE does not affect the AFL function. This means
that you can check the matrix signal while its output is muted.

GL2400 User Guide 21

MONITOR, TALKBACK and SIGNAL GENERATOR

TALKBACK

MIN MAX

OSC/NOISE

MINLMAX

1kHz
PINK

ON

SELECT

L-R

GRP
1-4

AUX
1-2

AUX
3-4

AUX
5-6

TALK

MIC

2TRK REPLAY

OO

+16

+9
+6
+3

0

-3

-6

-9

-12

-16

-20

-30

PFL
AFL

MONITOR

0

PHONES

+10

2TRK
TO LR

R

POWER

10

L-R
2TRK

Console Monitor

Comprehensive engineer’s headphones and
local monitoring is provided. Select either LR or 2-track return as the
default source using the L-R / 2TRK switch. 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.

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.

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.

TALKBACK Individually assignable talkback is available to all the

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.

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.

First select the source you wish to talk to. You can select the auxes in
pairs, useful for communicating with the performers on stage. The
four groups are selected simultaneously, ideal for identifying a
multitrack recording. You can also talk to LR, ideal 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.

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.

22 GL2400 User Guide

GL2400 Applications and Operating Tips

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
GL2400 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 The term used to describe the gain (level)

matching of the signal through the audio system chain. Each item in

CLIPPING

!

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.

NORMAL OPERATING RANGE

+20
+16
+12

+9
+6

HEADROOM

+3
+1

0

-1

-3

-6

-9

-12

-16

-20

-30

-40

-50

-60

-70

SIGNAL-TO-NOISE RATIO

-80

-90

SIGNAL

DYNAMIC RANGE

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.

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
GL2400 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 GL2400 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.

GL2400 User Guide 23

OSC/NOISE

MIN MAX

ON

SELECT

1kHz
PINK

L-R

GRP
1-4

AUX
1-2

AUX
3-4

AUX
5-6

Using the Oscillator / Noise Generator The GL2400

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.

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 groups and turn up GRP1 in the matrix. Set the matrix
GRP1 and LEVEL controls to their 3 o’clock ‘0’ positions. 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’.

GAIN

0

20

6-14 4060

The GL2400 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

30

40

50

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.

24 GL2400 User Guide

AFL

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 GL2400 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, aux and matrix 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.

dB

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 (Vo

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.

Tech talk…

2

/Ro / Vi2/Ri)

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

0dBV = 1V -10dBV = 316mV = -8dBu

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)

Using Inserts The GL2400 channel inserts operate at 0dBu,

the output inserts operate at -2dBu. In practice this makes little

☺ 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.

GL2400 User Guide 25

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.

TIP

RING

INSERT

SEND

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.

POLARITY

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.

EXT

EXT

EXT

IN IN

IN

OO

O+6

O +6

GRP

GRP

GRP

1

1

1

OO

O

+6

O +6

GRP

GRP

GRP

2

2

2

OO

O

+6

O +6

GRP

GRP

GRP

3

3

3

OO

O

+6

O +6

GRP

GRP

GRP

4

4

4

OO

O

+6

O +6

L

L

L

OO

O+6

O +6

R

R

R

OO

O

+6

O +6

LEVEL

LEVEL

LEVEL

OO

O

+6

O +6

MUTE

MUTE

AFL AFL

MTX1 MTX2 MTX3 MTX4

AUXOOAUX

AUX

0 0

3

1

2

OO+10 +10

AFL

AFL AF L

REV

REV

GRP2GRP1

TO LR

TO LR

PAN

PAN

PAN

R=L R=RL R=L

L

PK!

PK!

PK!

+6

+6

+6

0

0

0

SIG

SIG

SIG

MUTE MUTE MUTEMUTE MUTE MUTE

AFLAFL AFLAFLAFL AFL

10

10

10

5

5

5

0

0

0

5

5

5

10

10

10

20

20

20

30

30

30

00

00

00

EXT
IN

O

O +6

O

O +6

GRP

1

O

O +6

O

O +6

GRP

2

O

O +6

O

O +6

GRP

3

O

O +6

O

O +6

GRP

4

O

O +6

O

O +6

L

O

O +6

O

O +6

R

O

O +6

O

O +6

LEVEL

OO +6

OO +6

MUTE

AFL

AUX

0

4

OO +10OO

AFL

REV

PAN

PK!
+6
0
SIG

10

5

0

5

10

20

30

00

MIC

TALKBACK

MIN MAX

OSC/NOISE

2TRK REPLAY

OO

MINLMAX

1kHz
PINK

ON

+16
+9

SELECT

+6
+3
0

L-R

-3

-6

-9

GRP

-12

1-4

-16

-20

-30

AUX
1-2

PFL

AUX

AFL

3-4

MONITOR
AUX
5-6

MUTE

0

AFL

TALK

AUX

AUX

0

0

5

6

OO +10OO

+10

AFL

REV REV

REV

GRP4GRP3

LISTEN WEDGE

TO LRTO LR

=

MSOURCE

MONO (L+R)
AUX 6
(AUX FED SUB)

PK!

PK!

+6

+6

0

0

SIG

SIG

10

10

5

5

0

0

5

5

10

10

20

20

30

30

00

00

+48V

POLARITY

LINE LINE LINE LINE LINE LINE LINE LINE

(PAD) (PAD) (PAD) (PAD) (PAD) (PAD) (PAD) (PAD)

0

30
40

PHONES

20

GAIN

50

6-14 4060

HPF

100Hz

HF

12k

+10

-15

+15
3k

4k

1k

2TRK
TO LR

700

6k

500Hz

15k

HM

R

-15

+15
180

70

250

400

45

35Hz

1k

LM

-15

+15

LF

POWER

80Hz

-15

+15

EQ IN

10

AUX

1

L-R
2TRK

OO +6

AUX

2

0

OO +6

AUX

+10

3

AFL

OO +6

AUX

4

MODE

FOH

OO +6

MONITOR

POST
PRE

AUX

5

OO +6

AUX

6

PK!

+6OO

+6

POST

0

PRE

SIG

=

PAN

R

L

EVEN

ODD

MUTE

AFL

PFL

10

10

5

5

L-R

0

0

1-2

5

5

3-4

10

10

20

20

30

30

00

00

MRL4321

17

+48V

+48V

POLARITY

POLARITY

0

0

30

30

40

40

20

20

GAIN

GAIN

50

6-14

6-14

4060

HPF

HPF

100Hz

100Hz

HF

HF

12k

12k

-15

+15

-15

+15

3k

3k

4k

1k

1k

700

6k

700

500Hz

15k

500Hz

15k

HM

HM

-15

-15

+15

+15

180

180

70

250

70

400

45

45

35Hz

1k

35Hz

1k

LM

LM

-15

+15

-15

+15

LF

LF

80Hz

80Hz

-15

+15

-15

+15

EQ IN

EQ IN

AUX

AUX

1

1

OO +6

OO +6

AUX

AUX

2

2

OO +6

OO +6

AUX

AUX

3

3

OO +6

OO +6

AUX

AUX

4

4

OO +6

OO +6

POST

POST

PRE

PRE

AUX

AUX

5

5

OO +6

OO +6

AUX

AUX

6

6

+6OO

+6OO

POST

POST

PRE

PRE

=

=

PAN

PAN

R

L

L

ODD

EVEN

ODD

EVEN

MUTE

MUTE

PFL

PFL

10

10

5

5

L-R

L-R

0

0

1-2

1-2

5

5

3-4

3-4

10

10

20

20

30

30

00

00

19

18

+48V

+48V

+48V

POLARITY

POLARITY

POLARITY

0

0

0

30

30

30

40

40

40

20

20

20

GAIN

GAIN

GAIN

50

50

50

50

4060 6-14 4060 6-14 4060 6-14 4060 6-14 4060 6-14 4060

HPF

HPF

HPF

100Hz

100Hz

100Hz

HF

HF

HF

12k

12k

12k

-15

+15

-15

+15

-15

+15

3k

3k

3k

4k

4k

4k

4k

1k

1k

1k

6k

700

6k

700

6k

700

6k

500Hz

15k

500Hz

15k

500Hz

15k

HM

HM

HM

-15

-15

-15

+15

+15

+15

180

180

180

250

70

250

70

250

70

250

400

400

400

400

45

45

45

35Hz

1k

35Hz

1k

35Hz

1k

LM

LM

LM

-15

+15

-15

+15

-15

+15

LF

LF

LF

80Hz

80Hz

80Hz

-15

+15

-15

+15

-15

+15

EQ IN

EQ IN

EQ IN

AUX

AUX

AUX

1

1

1

OO +6

OO +6

OO +6

AUX

AUX

AUX

2

2

2

OO +6

OO +6

OO +6

AUX

AUX

AUX

3

3

3

OO +6

OO +6

OO +6

AUX

AUX

AUX

4

4

4

OO +6

OO +6

OO +6

POST

POST

POST

PRE

PRE

PRE

AUX

AUX

AUX

5

5

5

OO +6

OO +6

OO +6

AUX

AUX

AUX

6

6

6

+6OO

+6OO

+6OO

POST

POST

POST

PRE

PRE

PRE

=

=

=

PAN

PAN

PAN

R

R

R

R

L

L

L

ODD

EVEN

ODD

EVEN

ODD

EVEN

MUTE

MUTE

MUTE

PFL

PFL

PFL

10

10

10

5

5

5

L-R

L-R

L-R

0

0

0

1-2

1-2

1-2

5

5

5

3-4

3-4

3-4

10

10

10

20

20

20

30

30

30

00

00

00

22

21

20

+48V

+48V

POLARITY

POLARITY

0

0

30

30

40

40

20

20

GAIN

GAIN

50

HPF

HPF

100Hz

100Hz

HF

HF

12k

12k

-15

+15

-15

+15

3k

3k

4k

4k

1k

1k

700

700

6k

500Hz

15k

500Hz

15k

HM

HM

-15

-15

+15

+15

180

180

70

250

70

250

400

45

45

35Hz

1k

35Hz

1k

LM

LM

-15

+15

-15

+15

LF

LF

80Hz

80Hz

-15

+15

-15

+15

EQ IN

EQ IN

AUX

AUX

1

1

OO +6

OO +6

AUX

AUX

2

2

OO +6

OO +6

AUX

AUX

3

3

OO +6

OO +6

AUX

AUX

4

4

OO +6

OO +6

POST

POST

PRE

PRE

AUX

AUX

5

5

OO +6

OO +6

AUX

AUX

6

6

+6OO

+6OO

POST

POST

PRE

PRE

=

=

PAN

PAN

R

R

L

L

ODD

EVEN

ODD

EVEN

MUTE

MUTE

PFL

PFL

10

10

5

5

L-R

L-R

0

0

1-2

1-2

5

5

3-4

3-4

10

10

20

20

30

30

00

00

23

24

3231302928272625

Think before you hit
the switch!

50

6k

400

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. 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. These can also be downloaded from
our web site.

Turning the system on and off It is good practice to:

• Turn the amplifiers on last and off first.

• Mute channels before plugging cables, unplugging

instruments and switching phantom power.

• Let equipment which has been stored in a damp or cold

place acclimatise in the venue first before powering it up.

• Power up the system in plenty of time before you start the

sound check or show.

Sound levels The ear is a delicate instrument. Do not subject

yourself or any listener to long periods of loud sound, particularly with
extreme equalisation. This may result in frequency selective or full
range hearing loss. Adhere to the sound level regulations which may
apply to the venue… and common sense!

26 GL2400 User Guide

FOH / Monitor

Protected

Aux Reverse

Master Control

XLR + Inserts

Pre/Post

Sub Grouping

Matrix Feed

Listen Wedge

Talkback

Ambience

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 GL2400 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.

• To prevent accidental operation during the show, the configuration mode

switches are safely recessed under the panel.

• In FOH mode

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

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

• In Monitor mode

you can still work with grouped level control to the main mix.

• In Monitor mode

can create independent mixes in addition to the auxes for special feeds,
recording, and further mono or stereo in-ear monitors.

• In Monitor mode

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.

the groups and LR are the main outputs while in Monitor

the aux outputs are routed to the console main XLR

, the pre-insert, pre-EQ or post-EQ option is needed.

the groups continue to feed the sub grouping to LR so that

the groups and LR continue to feed the matrix so that you

the M output becomes the engineer’s ‘listen wedge’ feed

FOH

LR + M

Aux-fed Subs

Aux-fed C

4 Groups

6 Auxes

4 Matrix

GL2400 User Guide 27

Monitor

10 Monitors

6 Aux (wedge)

4 Matrix (IEM)

Engineer’s Wedge

Ambience

Talkback

Recording

Stereo / Mono

2-Track

4 Groups

4 Matrix

Direct Outputs

Ambience

EXT

IN IN

OO

GRP

1

OO

+6

GRP

2

OO

+6

GRP

3

OO

+6

GRP

4

OO

+6

L

OO

R

OO

+6

LEVEL

OO

+6

MUTE

AFL AFL

EXT

GRP

GRP

GRP

GRP

LEVEL

1

2

3

4

L

R

O+6

O +6

O

O +6

O

O +6

O

O +6

O

O +6

O+6

O +6

O

O +6

O

O +6

MUTE

EXT
IN

GRP

1

GRP

2

GRP

3

GRP

4

LEVEL

L

R

O

O +6

O

O +6

O

O +6

O

O +6

O

O +6

O

O +6

O

O +6

OO +6

Applications for the Matrix The matrix is a ‘mixer within a

EXT

IN

O

O +6

GRP

1

O

O +6

GRP

2

O

O +6

GRP

3

O

O +6

GRP

4

O

O +6

L

O

O +6

R

O

O +6

LEVEL

OO +6

MUTE

MUTE

AFL

AFL

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 and an external input as dialled up on the 7 source
rotaries (hence a ‘7x4’ 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:

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.

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).

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. You can check your level in the headphones
before you send it by muting the matrix and selecting AFL.

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.

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.

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.

Additional Monitor Mixes You could 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.

28 GL2400 User Guide

MONITOR

OUT

MATRIX

EXT

EXT
IN IN IN IN

3421

MTX

MTX

3

4

INSERTLINSERT4INSERT3INSERT2INSERT1INSERT

R

AUX5AUX4AUX3AUX2AUX1AUX

6

R L GRP 4GRP 3GRP 2GRP 1

AUX 5 AUX 4 AUX 3 AUX 2 AUX 1

MATRIX EXT IN

LR

EXT

EXT

MTX

MTX

2

LAMP

IN1

IN2

IN3

IN4

1

(BREAKPOINT)

MIC OUT

L/M

R

GRP/AUX REVERSE

MIC OUT

ST4 ST3 ST2 ST1

L/M

L/MRL/M

R

R

MIC INMIC IN

1516

Create IEM Mixes with Ambience In Monitor mode the

matrix continues to be fed with the 4 groups, L and R mixes. You can
use these to create additional, independent monitor mixes. Together
with the auxes these give you as many as 10 mixes. Create mono or
stereo in-ear monitor feeds using single or paired matrices, for

1516

example MTX1-2 and 3-4. You could use LR to start with a basic
stereo mix, then add up to four instrument or ‘more me’ groups. Add
ambience using a pair of jack leads to patch the stereo channel MIC
Outputs 15 and 16 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

1

AUX

2

AUX

3

AUX

4

AUX

5

AUX

6

OO +6

OO +6

OO +6

OO +6

OO +6

POST
PRE

+6OO

POST
PRE

Recording with the GL2400 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-insert, pre-EQ 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-EQ, and post-fade if you prefer. Post-EQ lets you use the EQ for
source correction to affect both live sound and recording. Remember
to use some ambience microphones to record the audience and
venue atmosphere too.

Pre/post Fade Aux Settings The aux sends are switched pre

or post fader using two PRE switches on every channel. One switch
affects auxes 1-4, the other auxes 5 and 6. It is usual to set auxes pre­fade 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.

GL2400 User Guide 29

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 and keyboards, 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.

TOP TOP

STEREO CROSSOVER

SUB

AUX 6 (POST-FADE)

MONO CROSSOVER

R

SUB

ML

AUX6 MODE

The sub can be separately driven in several ways, for
example using a group, a mono or ‘C’ bus, or using an aux.
Using an aux send has become a popular method on the
smaller consoles. Simply feed the LR to a stereo crossover
to drive the top speakers, and a post-fade aux send 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. 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.

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.

GL2400

The GL2400 overcomes this with an innovative mode
switch above the master faders that routes the AUX6 mix
master through the M fader and on to the XLR output. This
switch is recessed for protection against accidental
operation. The result is you get three master faders aligned
for simultaneous control, individual mutes, AFL and meters,
and three properly balanced XLR outputs. Note that the
AUX6 rotary master does not affect this sub feed. It does
however independently affect the AUX6 jack output. This
gives you a further advantage that another sub can be
separately controlled using the rotary master, for example to
supplement the stage monitor mix.

Creating a separate C mix As with the aux-fed sub mix

L

CR

described above, you can set the mode switch to create an
independent mix feeding a dedicated centre or mono speaker. The
channel AUX6 sends become the routing to this mix while the M fader
with XLR output becomes the master, correctly aligned with the L and
R faders. Set the channel aux sends to unity 3 o’clock position, and
release the LR routing switches if you do not want the signal in the LR
speakers as well. The GL2400 gives you the choice of either
mixing the sum of L and R to the M output (mode switch up), or an
independent AUX6 mix to M (mode switch pressed).

OUT M

Other M Output Applications Apart from the aux-fed subs

and C mix described above, other examples include L+R sum mono
fill, additional mono zone feed, mono recording, mono PA with LR
providing two subgroups to M or a stereo recording… and more.

30 GL2400 User Guide

DIRECT

OUT

24

MIC OUT

(BREAKPOINT)

MIC OUT

1516

ST4 ST3 ST2 ST1

L/M

R

L/M

L/M

R

R

L/M

R

Using the channel Direct Outputs Default factory setting is

pre-insert, pre-EQ, pre-fade so that your live fader mixing, effects and
EQ do not affect the recording. Change this to post-EQ using internal
jumpers if you prefer to use the EQ for source correction affecting the
recording too. 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 post­fade by setting internal jumpers. Use post for feeding an effects
processor with one source only, for example a dedicated reverb on
lead vocals, or to add more of one source into a matrix fed recording.

Using the Stereo Channels Stereo channels 15 and 16

present a unique flexibility. Each provides a microphone input and
two stereo inputs, a total of five connections which can feed the
channel or be routed elsewhere. 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. Each stereo input has its own level
control and can be routed either into the channel or directly to the LR
mix. This is configured using a recessed mode switch which protects
it from accidental operation during a show. With 2 mic and 4 stereo
line inputs, channels 15 and 16 provide for a host of space saving
applications:

+48V

30

40

20

MIC

GAIN

6

60

0

-5

ST1

-10

-20

16

O

O

STEREO

CH15

LR

0

-5

ST2

-10

-20

16

O

O

STEREO

CH15 CH16

LR

MIC INMIC IN

1516

Standard Mono Microphone Channels Mono mic input through the
channel with 4band EQ, auxes and full routing. Press the mode
switches to re-route the stereo inputs direct to LR for simple effects
returns and source inputs.

True Stereo Microphone Channel For example, use short jack
leads to patch both channel 15 and 16 MIC OUT breakpoints into ST2
stereo line input. Set ST2 level control to its mid ‘0dB’ position to feed
the channel. Adjust the gain and balance between the left and right
microphones using the two mic GAIN controls. Route ST1 to LR as a

+48V

30

40

20

MIC

GAIN

50

ST3

5

5

-10

-20

10

STEREO

ST4

-10

-20

10

STEREO

50

60

6

0

-5
5

10

16

O

O

CH16

LR

0

-5
5

10

16

O

O

LR

simple effects return or source input. The other channel can be used
as a dual stereo input fed from ST3/4, or as a single ST4 input with
ST3 routed independently to LR.

Mixing Two Microphones through One Channel As above but
patch CH15 MIC OUT into ST1 L/M, and channel 16 MIC OUT into ST2
L/M. Set ST1 and 2 levels to mid ‘0dB’ position. This mixes the two
mics together in mono, for example when using one channel for two
choir microphones. CH16 is available for stereo line sources.

Patchable Microphone Preamplifier 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 the 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.

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.

GL2400 User Guide 31

Specifications

Performance

Maximum input level Mic +34dBu (inc pad)
CH Line +34dBu
Other Line +20dBu

Maximum output level XLR +26dBu
Jack +20dBu

Internal headroom Channels +20dB
Mix +22dB

Meters 3 colour LED, quasi peak response
Sensitivity 0VU = +4dBu at XLR output
Master meters 12 segment -30 to +16dB
Channel meters 4 segment -12,0,+6+16dB (5dB before clip)

Frequency response 20Hz to 50kHz +/-0.5dB

Mic CMRR at 1kHz > 80dB typical

THD+n at +14dBu 1kHz Channel to mix out < 0.003%

Crosstalk at 1kHz Fader shutoff >90dB
Mute shutoff >90dB
Inter channel >90dB

Noise, rms 22Hz to 22kHz Mic EIN -128dB
Residual output noise < -96dBu (-100dB S/N)
LR mix noise 16 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 16 line 0dB gain < -86dB S/N

Channel HPF 12dB/octave below 100Hz

Mono EQ HF Shelving +/-15dB, 12kHz
HM Peak/dip +/-15dB, 500Hz to 15kHz, Q=1.8
LM Peak/dip +/-15dB, 35Hz to 1kHz, Q=1.8
LF Shelving +/-15dB, 80Hz

Stereo EQ HF Shelving +/-15dB, 12kHz
HM Peak/dip +/-15dB, 2.5kHz, Q=1.8
LM Peak/dip +/-15dB, 250Hz, Q=1.8
LF Shelving +/-15dB, 80Hz

Power supply (16-32 ch) Internal switched mode, auto sensing, IEC input
External input for optional MPS12 backup supply

Power supply (40 ch) External RPS11 linear, IEC input
Console Input for second RPS11 as backup supply

Mechanical

16 24 32 40

Width 609mm (24”) 817mm (32.2”) 1025mm (40.4”) 1233mm (48.5”)
Depth 560mm (22”)
Height 150mm (5.9”)

Weight 16.5kg(36.3lbs) 21.5kg(47.3lbs) 26.5kg(58.3lbs) 32kg(70.5lbs)

32 GL2400 User Guide

Connections

Mono channel XLR balanced pin 2 hot Sensitivity -60 to +14dBu
TRS balanced, tip hot Sensitivity -40 to +14dBu
Pad out (MIC) 2k ohm
Pad in (MIC or LINE) >10k ohm, -20dB attenuation
Max input level +34dBu
XLR phantom power +48V, on/off

Stereo channel ST1,3 TRS unbalanced >10k ohm, -16 to +20dBu
ST2,4 TRS balanced >10k ohm, -16 to +20dBu

Talkback mic XLR balanced pin 2 hot Sensitivity -50 to -10dBu
Phantom power Internal jumper +48V

2-track return TRS unbalanced >4k ohm, -2dBu

2-track send TRS impedance balanced <75 ohm, -2dBu

Inserts Channel TRS, tip send, ring return, 0dBu
Output TRS, tip send, ring return, -2dBu

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 1-6 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 TRS, tip L, ring R, 30 to 600 ohm headphones recommended

Monitor output TRS impedance balanced <75 ohm, -2dBu, +20dBu max

Lamp 4-pin XLR max 12V 5W lamp

GL2400 Series Part Numbers

14 mic/line, 2 mic/dual stereo, 4 group console GL2400-16/v
22 mic/line, 2 mic/dual stereo, 4 group console GL2400-24/v
30 line, 2 mic/dual stereo, 4 group console GL2400-32/v
38 line, 2 mic/dual stereo, 4 group console GL2400-40/v

Sys-Link V2 input/output option kit GL2400-SLV2

SSM2142P balanced output driver option IC AE0302
DRV134 balanced output driver option IC (alternative to above) AE5725

Backup power supply option for the 16, 24 and 32 models MPS12/v
Backup power supply option (for the 40 channel model RPS11/v

Allen & Heath 18” gooseneck LED lamp – right angled LEDLAMP-X

GL2400 User Guide 33

GL2400

48V

MIC

BALANCED

INSERT

0dBu

LINE

2= +

TIP= +

LINE/PAD

-20dB

TIP= SEND

RING= RETURN

MIC/MONO INPUTS

DIRECT OUT

0dBu

IMPEDANCE BALANCED

48V

MIC OUT

0dBu

(break jack)

L/M

INPUT ST1(3)

MIC

2= +

TIP= +

RING= -

GAIN

GAIN

+

-

R

+

L/M

­GAIN

INPUT ST2(4)

+

R

-

MIC/STEREO INPUTS

48V PHANTOM POWER

OFF

TALKBACK

MIC IN

2= +

BALANCED

PHANTOM POWER

GAIN

POL

+

-

TIP= +

RING= -

PHANTOM POWER

CH

LR

ON

PFL

AUX 1-6

GRP 1-4

LR

EQ IN

METER

FADER

PFL

MUTE

PAN

L-R

1-2

AUX MIX

GRP/AUX REV

SL

3-4

4 BAND EQUALISER

HF

HPF

HM

LM

LF

GRP MIX

SL

PRE-FADE

POST-FADE

POST-EQ

PRE-INSERT, PRE-EQ

C

D

P = PRE-FADE
S = SWITCHED
A = POST-FADE

B

A

FEJU MPER GH

2

1AUX

PRE

PASP

354

PRE

IJKL

SSAS

6

AFL

AUX

+10dB boost

GROUPS / AUX 1-4

INSERT

+10dB boost

-2dBu

FADER

AFL

AFL

+4dBu BAL OPTION

METER

MUTE

SYS-LINK CONNECTION

IMPEDANCE BALANCED

BAL

2 = +

TO MATRIX

PAN

L-R

SL

AUX OUT

TIP= +

-2dBu

GROUP OUT

+4dBu

LR/AUX REV

SL

METER

+

MUTE

PRE-FADE

CN4

PFL

SM

+

FADER

MONO/STEREO AUX

POST-FADE

+

PAN

L-R

1-2

3-4

SM

CN5

4 BAND EQUALISER

HF

HM

+

LM

CH

LF

SUM

EQ IN

LR

PRE PRE

AUX MIX

L(R) MIX

SL

IN1

IN2

IN3

IN4

MATRIX EXT IN

JUMPER OPTIONS KLIJGHEFCDAB

P = PRE-FADE
S = SWITCHED
A = POST-FADE

P SSP PSP SS A A S

AUX

1

2

43

65

6

FROM GRP,L,R

EXT IN

GRP1

GRP2

AUX

+10dB boost

L(R) / AUX 5(6)

FADER

+10dB boost

INSERT

-2dBu

MATRIX EXT IN NORMALLING
FOR COMMON MONO OR STEREO SOURCE

AFL disable in WEDGE mode

0dBu

FROM L,R

FROM AUX6

SUM

+

FROM PFL/AFL

AFL

MUTE

AUX6

WEDGE MODE

+4dBu BAL OPTION

METER

MONO

FADER

+10dB boost

AUX OUT

TIP= +

IMPEDANCE BALANCED

-2dBu

L(R) OUT

BAL

2 = +

+4dBu

TO MATRIX, MONO, MONITOR, 2TRK

METER

AFL

MUTE

M OUT

BAL

2 = +

+4dBu

GRP3

GRP4

GAIN

MATRIX MIX

L

1KHz OSC

PINK NOISE

LEVEL

ON

DIM

PRESS TO TALK

+

-

L-R

GRP1-4

AUX1-2

AUX3-4

AUX5-6

PFL/AFL DC

FROM L,R

PFL/AFL MIX

R

MATRIX 1-4

SL

SL

SEND

2-TRACK

L

-2dBu

R

+10dB boost

RETURN

L/M

TO WEDGE MODE

R

LEVEL

MUTE

AFL

MATRIX OUT

TIP= +

IMPEDANCE BALANCED

-2dBu+4dBu BAL OPTION

MONITOR

L

R

MONITOR

MONITOR OUT

L

PHONES OUT

TIP = LEFT
RING = RIGHT

R

2TRK TO LR

LR/2-TRK

PFL/AFL

IMPEDANCE BALANCED

34 GL2400 User Guide

User Options

The GL2400 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.

Remove the base Switch off power and unplug 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 T10 driver to remove
the two M3x12mm screws holding the base to the underside of the internal
power unit. 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.

AUX PRE/POST INSERT/EQ

AUX PRE/POST FADER

DIRECT OUT PRE/POST FADER

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.

AUX5
BALANCE

TB MIC
+48V

MASTER L

U7

VR3

AUX6
BALANCE

MASTER R

MONO INPUT

STEREO INPUT

AUX STEREO/MONO

AUX PRE/POST FADER

CN6

MATRIX 1-4
BALANCE

AUX 1-4
BALANCE

GROUP

U9

U7

U7

GL2400 User Guide 35

MONO CH - PRE-FADE AUX SENDS

PREFADE SEL

A=PRE EQ

POST-EQ

PREFADE SEL

A=PRE EQ

PRE-INSERT, PRE-EQ

MONO CH - AUX PRE/POST FADER SETTINGS

PO

SW

AUX 6

SW = PRE/POST SWITCH
PR = PRE-FADE
PO = POST-FADE

STEREO CH - AUX PRE/POST FADER SETTINGS

SW

6 1

AUX 5 4 3 2

DCAB

MONO CH - DIRECT OUTPUT

DCAB

PRE-FADE

POST-FADE

PR

PR

PO

SW

SW

53-4

SW

1-2

B

CDEFGHIKLJ

A

PRSWPRSWPRSWPRSWPOSWPO

DIR O/P

C=PRE

DIR O/P

C=PRE

Aux pre/post EQ

Factory default for the mono
channel pre-fade auxes is pre-insert, pre-EQ. This is
popular with many users mixing monitors from FOH.
It prevents the channel EQ and inserted
compressors affecting the monitor mix. Move the
jumper from A to B to change this to post-insert,
post-EQ if preferred, for example when using
corrective EQ affecting FOH and monitors. Note that
auxes are always post-mute.

Direct output source Factory default is pre-

fader (as set for the pre-fade auxes). This is
common for live recording to multitrack. The live mix
fader movements do not affect the recording. Move
the jumper from C to D to change to post-fade.
Post-fade is appropriate when using the output as a
direct channel effects send.

Channel Aux pre/post settings Factory

default is Aux 1-4 = switched, Aux 5-6 = switched
pre/post fader. You can change these settings for
different combinations of permanent or switched
pre/post fade auxes by repositioning the links. Note
that these are solder links on the mono channels.
Refer to the system block diagram to explore the
possibilities. 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.

STEREO CH - MONO/STEREO AUXES

CN5

CN4

POST-FADE AUXES

STEREOMONO

PRE-FADE AUXES

STEREOMONO

L MASTER - TALKBACK +48V

JP2JP1

PHANTOM POWER

GND +48V

Stereo/Mono aux source The stereo

channels feed the auxes with a mono sum of L+R.
This can be changed so that L feeds the odd
numbered auxes, and R the even. This may be
preferred when using odd/even auxes as stereo
pairs. Factory default is the mono setting.

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 GND 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.

36 GL2400 User Guide

MATRIX 1-4

BALANCE

GROUP

MASTER L

MASTER R

Output balance options The aux and matrix

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.

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

AUX 1-4
BALANCE

AUX5
BALANCE

SLAVE CONSOLE

GL2400

SYS-LINK V2 OUTPUT SYS-LINK V2 INPUT

37WAY CABLE

MASTER CONSOLE

SYS-LINK V2 OUTPUT

GL2400 OR OTHER A&H CONSOLE

SYS-LINK V2 INPUT

AUX6
BALANCE

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

plate is fitted here as standard. This may be
replaced with an optional card which provides the
console inputs, outputs and PFL system on two
37way D connectors for linking to other Allen &
Heath consoles already fitted with Sys-Link V2. The
GL2400 can become an input channel expander
(slave) or have its number of input channels
expanded (master) when linked to other consoles.

A 37way shielded multi-core cable carries the
balanced mix signals and PFL/AFL system to or from
the other console.

IMPORTANT: Note that you need a 37 to 25way
adapter cable if you are connecting Sys-Link V2
(Version 2) to the older Sys-Link V1 (Version 1)
standard.

For full details please refer to the Sys-Link option
Applications Note AP6050 and Fitting Instructions
AP6049.

A blank

GL2400 User Guide 37

Cue Sheet 1 of 3 GL2400 Master Section

Copy and use this page to record your console settings.

GL2400

EXT

IN IN

OO

GRP

1

OO

GRP

2

OO

GRP

3

OO

GRP

4

OO

L

OO

R

OO

LEVEL

OO

MUTE

AFL AFL

AUX

1

OO

AFL

REV

TO LR

PAN

L

PK!
+6

0

SIG

EXT

O+6

O +6

GRP

1

O

+6

O +6

GRP

2

O

+6

O +6

GRP

3

O

+6

O +6

GRP

4

O

+6

O +6

L

O+6

O +6

R

O

+6

O +6

LEVEL

O

+6

O +6

AUX

0 0

2

OO+10 +10

REV

=

PAN

R=L R

PK!
+6

0

SIG

GRP2GRP1
TO LR

MUTE

AFL

EXT

IN

O

O +6

GRP

1

O

O +6

GRP

2

O

O +6

GRP

3

O

O +6

GRP

4

O

O +6

L

O

O +6

R

O

O +6

LEVEL

OO +6

AUX

3

OO +10 OO

REV

PAN

PK!
+6

0

SIG

MUTE

AFL

0

AFL

EXT

IN

O

O +6

GRP

1

O

O +6

GRP

2

O

O +6

GRP

3

O

O +6

GRP

4

O

O +6

L

O

O +6

R

O

O +6

LEVEL

OO +6

AUX

4

REV REV

GRP4GRP3
TO LRTO LR

=

PAN

PK!
+6

0

SIG

TALKBACK

MIC

PHONES

MIN MAX

OSC/NOISE

MUTE

AFL

AUX

0

5

+10

AFL

RL R=L

PK!
+6

0

SIG

MINLMAX

1kHz
PINK

ON

SELECT

L-R

GRP
1-4

AUX
1-2

AUX
3-4

AUX
5-6

TALK

0

OO +10 OO

AFL

PK!
+6

SIG

2TRK REPLAY

AFL

MONITOR

AUX

6

0

OO

+16

+9
+6
+3

0

-3

-6

-9

-12

-16

-20

-30

PFL

0

REV

M SOURCE

+10

2TRK
TO LR

R

POWER

10

L-R
2TRK

0

+10

AFL

LISTEN WEDGE

MONO (L+R)
AUX 6

(AUX FED SUB)

PK!
+6

SIG

MODE

FOH
MONITOR

0

MUTE MUTE

AFLAFL

GRP1 GRP2 GRP3 GRP4 L R M

AUX1 AUX2 AUX3 A UX4 AUX5 A UX6 LISTEN

10

10

10

5

0

0

5

10

20

20

30

30

0

0

10

5

5

0

5

5

10

20

30

0

0

0

0

10

5

0

5

10

20

30

0

0

MUTEMUTE MUTE

AFLAFLAFL

10

5

0

5

10

20

30

0

0

MUTE

AFL

AFL

10

10

5

5

0

0

5

10

20

30

0

5

10

20

30

0

0

0

1234 LRM

38 GL2400 User Guide

Cue Sheet 2 of 3 GL2400 8 Mono

Copy and use this page to record your console settings.

+48V

POLARITY

LINE

(PAD)

0

30

40

20

GAIN

6-14

HPF

100Hz

HF

12k

-15

+15

3k

4k

1k

700

500Hz

15k

HM

-15

+15

180

70

250

45

35Hz

1k

LM

-15

+15

LF

80Hz

-15

+15

EQ IN

AUX

1

OO +6

AUX

2

OO +6

AUX

3

OO +6

AUX

4

OO +6

POST
PRE

AUX

5

OO +6

AUX

6

+6OO

POST
PRE

=

PAN

L

R

EVEN

ODD

MUTE

PFL

+48V

POLARITY

LINE

(PAD)

0

30

40

20

GAIN

50

4060

6-14

4060

HPF

100Hz

HF

12k

-15

+15

3k

4k

1k

6k

700

500Hz

15k

HM

-15

+15

180

70

LM

80Hz

LF

AUX

1

AUX

2

AUX

3

AUX

4

AUX

5

AUX

6

PAN

45

35Hz

-15

-15

ODD

OO +6

OO +6

OO +6

OO +6

OO +6

=

L

EQ IN

+15

+15

EVEN

MUTE

1k

POST
PRE

+6OO

POST
PRE

250

400

R

400

PFL

+48V

POLARITY

LINE

(PAD)

0

30

40

20

GAIN

50

6-1 4

HPF

100Hz

HF

12k

-15

+15

3k

4k

1k

6k

700

500Hz

15k

HM

-15

+15

180

70

250

45

35Hz

1k

LM

-15

+15

LF

80Hz

-15

+15

EQ IN

AUX

1

OO +6

AUX

2

OO +6

AUX

3

OO +6

AUX

4

OO +6

POST
PRE

AUX

5

OO +6

AUX

6

+6OO

POST
PRE

=

PAN

L

R

EVEN

ODD

MUTE

PFL

+48V

POLARITY

LINE

(PAD)

0

30

40

20

GAIN

50

4060

6-14

HPF

100Hz

HF

12k

-15

+15

3k

4k

1k

6k

700

500Hz

15k

HM

-15

+15

180

70

LM

LF

80Hz

AUX

AUX

AUX

AUX

AUX

AUX

PAN

1

2

3

4

5

6

45

35Hz

-15

-15

L

ODD

EQ IN

OO +6

OO +6

OO +6

OO +6

OO +6

=

+15

+15

EVEN

MUTE

1k

POST
PRE

+6OO

POST
PRE

250

R

400

PFL

+48V

POLARITY

LINE

(PAD)

0

30

40

20

GAIN

50

4060

6-14

4060

HPF

100Hz

HF

12k

-15

+15

3k

4k

1k

6k

700

500Hz

15k

HM

-15

+15

180

70

LM

LF

80Hz

AUX

AUX

AUX

AUX

AUX

AUX

PAN

1

2

3

4

5

6

45

35Hz

-15

-15

ODD

OO +6

OO +6

OO +6

OO +6

OO +6

=

L

EQ IN

+15

+15

EVEN

MUTE

1k

POST
PRE

+6OO

POST
PRE

250

R

400

PFL

+48V

POLARITY

LINE

(PAD)

0

30

40

20

GAIN

50

6-14

4060

HPF

100Hz

HF

12k

-15

+15

3k

4k

1k

6k

700

500Hz

15k

HM

-15

+15

180

70

LM

LF

80Hz

AUX

AUX

AUX

AUX

AUX

AUX

PAN

1

2

3

4

5

6

45

35Hz

-15

-15

ODD

OO +6

OO +6

OO +6

OO +6

OO +6

=

L

EQ IN

+15

+15

MUTE

1k

POST
PRE

+6OO

POST
PRE

EVEN

250

400

R

400

PFL

+48V

POLARITY

LINE

(PAD)

0

30

40

20

GAIN

50

6-1 4

4060

HPF

100Hz

HF

12k

-15

+15

3k

4k

1k

700

6k

500Hz

15k

HM

-15

+15

180

70

250

400

45

35Hz

1k

LM

-15

+15

LF

80Hz

-15

+15

EQ IN

AUX

1

OO +6

AUX

2

OO +6

AUX

3

OO +6

AUX

4

OO +6

POST
PRE

AUX

5

OO +6

AUX

6

+6OO

POST
PRE

=

PAN

L

R

EVEN

ODD

MUTE

PFL

+48V

POLARITY

LINE

(PAD)

0

30

40

20

GAIN

50

6k

HF

12k

HM

LM

LF

80Hz

AUX

AUX

AUX

AUX

AUX

AUX

PAN

1

2

3

4

5

6

700

500Hz

45

35Hz

6-14

-15

1k

-15

70

-15

-15

OO +6

OO +6

OO +6

OO +6

OO +6

L

ODD

50

4060

HPF

100Hz

+15

3k

4k

6k

15k

+15

180

250

400

1k

+15

+15

EQ IN

POST
PRE

+6OO

POST
PRE

=

R

EVEN

MUTE

PFL

PK!

+6

0

SIG

L-R

1-2

3-4

PK!

10

+6

0

SIG

5

L-R

0

1-2

5

3-4

10

20

30

00

PK!

10

+6

0

SIG

5

L-R

0

1-2

5

3-4

10

20

30

00

PK!

10

+6

0

SIG

5

L-R

0

1-2

5

3-4

10

20

30

00

PK!

10

+6

0

SIG

5

L-R

0

1-2

5

3-4

10

20

30

00

PK!

10

+6

0

SIG

5

L-R

0

1-2

5

3-4

10

20

30

00

PK!

10

+6

0

SIG

5

L-R

0

1-2

5

3-4

10

20

30

00

PK!

10

5

0

5

10

20

30

00

10

+6

0

SIG

5

L-R

0

1-2

5

3-4

10

20

30

00

GL2400 User Guide 39

Cue Sheet 3 of 3 GL2400 6 Mono, 2 Stereo

Copy and use this page to record your console settings.

+48V

POLARITY

LINE LINE LINE LINE LINE LINE

(PAD) (PAD) (PAD) (PAD) (PAD) (PAD)

0

30

40

20

GAIN

50

6-1 4 4060 6-14 4060

HPF

100Hz

HF

12k

-15

+15

3k

1k

4k

700

6k

500Hz

15k

HM

-15

+15

180

70

250

45

400

35Hz

1k

LM

-15

+15

LF

80Hz

-15

+15

EQ IN

AUX

1

OO +6

AUX

2

OO +6

AUX

3

OO +6

AUX

4

OO +6

POST
PRE

AUX

5

OO +6

AUX

6

+6OO

POST
PRE

=

PAN

R

L

ODD

EVEN

MUTE

PFL

+48V

POLARITY

0

30

40

20

GAIN

HPF

100Hz

HF

12k

-15

+15

3k

1k

4k

700

500Hz

15k

HM

-15

+15

180

70

250

45

35Hz

1k

LM

-15

+15

LF

80Hz

-15

+15

EQ IN

AUX

1

OO +6

AUX

2

OO +6

AUX

3

OO +6

AUX

4

OO +6

POST
PRE

AUX

5

OO +6

AUX

6

+6OO

POST
PRE

=

PAN

R

L

ODD

EVEN

MUTE

PFL

+48V

POLARITY

0

30

40

20

GAIN

50

6-14

HPF

100Hz

HF

12k

-15

+15

3k

1k

4k

700

6k

500Hz

15k

HM

-15

+15

180

70

250

45

400

35Hz

1k

LM

-15

+15

LF

80Hz

-15

+15

EQ IN

AUX

1

OO +6

AUX

2

OO +6

AUX

3

OO +6

AUX

4

OO +6

POST
PRE

AUX

5

OO +6

AUX

6

+6OO

POST
PRE

=

PAN

R

L

ODD

EVEN

MUTE

PFL

+48V

POLARITY

0

20

GAIN

50

6-14

4060

HF

12k

-15

1k

700

6k

500Hz

HM

-15

70

45

400

35Hz

LM

-15

LF

80Hz

-15

AUX

1

OO +6

AUX

2

OO +6

AUX

3

OO +6

AUX

4

OO +6

AUX

5

OO +6

AUX

6

PAN

L

ODD

0

30

HPF

100Hz

+15

3k

15k

+15

180

+15

+15

EQ IN

=

EVEN

MUTE

30

40

20

GAIN

50

4060 6-14 4060 6-14 4060

HF

12k

-15
3k

1k

4k

700

6k

500Hz

HM

-15
180

70

250

45

400

35Hz

1k

LM

-15

LF

80Hz

-15

AUX

1

OO +6

AUX

2

OO +6

AUX

3

OO +6

AUX

4

OO +6

POST
PRE

AUX

5

OO +6

AUX

6

+6OO

POST
PRE

R

=

PAN

L

ODD

PFL

+48V

POLARITY

40

HPF

100Hz

+15

4k

15k

+15

250

1k

+15

+15

EQ IN

POST
PRE

+6OO

POST
PRE

R

EVEN

MUTE

PFL

+48V

POLARITY

0

30

40

20

GAIN

HM

LM

80Hz

PAN

HF

12k

LF

AUX

1

AUX

2

AUX

3

AUX

4

AUX

5

AUX

6

700

500Hz

45

35Hz

ODD

-15

1k

-15

70

-15

-15

OO +6

OO +6

OO +6

OO +6

OO +6

L

50

HPF

100Hz

+15

3k

4k

6k

15k

+15

180

250

400

1k

+15

+15

EQ IN

POST
PRE

+6OO

POST
PRE

=

R

EVEN

MUTE

50

6k

400

PFL

+48V

30

20

MIC

GAIN

6

0

-5

ST1

-10

-20

O

O

STEREO

CH15

LR

0

-5

ST2

-10

-20

O

O

STEREO

CH15 CH16

LR

HF

12k

-15

+15

HM

2k5

-15

+15

LM

250Hz

-15

+15

LF

80Hz

-15

+15

EQ IN

AUX

1

OO +6

AUX

2

OO +6

AUX

3

OO +6

AUX

4

OO +6

AUX

5

OO +6

AUX

6

=

BAL

L

ODD

EVEN

MUTE

PFL

40

60

16

16

POST
PRE

+6OO

POST
PRE

+48V

30

40

20

MIC

GAIN

50

5

10

STEREO

5

10

STEREO

50

60

6

0

-5

ST3

5

-10

-20

10

16

O

O

CH16

LR

0

-5

ST4

5

-10

-20

10

O

O

16

LR

HF

12k

-15

+15

HM

2k5

-15

+15

LM

250Hz

-15

+15

LF

80Hz

-15

+15

EQ IN

AUX

1

OO +6

AUX

2

OO +6

AUX

3

OO +6

AUX

4

OO +6

POST
PRE

AUX

5

OO +6

AUX

6

+6OO

POST
PRE

=

BAL

R

R

L

ODD

EVEN

MUTE

PFL

PK!
+6

0

SIG

L-R

1-2

3-4

PK!

10

+6

0

SIG

5

L-R

0

1-2

5

3-4

10

20

30

00

PK!

10

+6

0

SIG

5

L-R

0

1-2

5

3-4

10

20

30

00

PK!

10

+6

0

SIG

5

L-R

0

1-2

5

3-4

10

20

30

00

PK!

10

+6

0

SIG

5

L-R

0

1-2

5

3-4

10

20

30

00

PK!

10

+6

0

SIG

5

L-R

0

1-2

5

3-4

10

20

30

00

PK!

10

+6

0

SIG

5

L-R

0

1-2

5

3-4

10

20

30

20

30

00

PK!

10

5

0

5

10

10

+6

0

SIG

5

L-R

0

1-2

5

3-4

10

20

30

00

0

0

40 GL2400 User Guide