Alesis DEQ224 User Manual

Reference Manual

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Table Of Contents

Introduction ..................................................................3

Welcome!......................................................................................................3

DEQ224 Key Features .................................................................... 4

How to Use This Manual................................................................ 5

Important Safety Instructions..................................7

Important Safety Instructions (English)................................... 7

Safety symbols used in this product.........................................................7

Please follow these precautions when using this product: ...................7

Instructions de Sécurité Importantes (French) ...................... 9

Symboles utilisés dans ce produit.............................................................9

Veuillez suivre ces précautions lors de l’utilisation de

l’appareil: ...................................................................................................... 9

Lesen Sie bitte die folgende Sicherheitshinweise

(German) ........................................................................................... 11

Sicherheit Symbole verwendet in diesem Produkt.................................11

Folgen Sie bitte diesen Vorkehrungen, wenn dieses

Produkt verwendet wird: ........................................................................... 11

CE Declaration Of Conformity..................................................... 13

FCC Compliance Statement ......................................................... 13

Chapter One: Quick Start Guide .............................. 15

If you can't wait to get started..................................................................15

Step 1: Hook it up to a mixer ........................................................ 15

Step 2: Try some equalization ...................................................... 16

Step 3: Try a filtering effect.......................................................... 16

Step 4: Store the Program............................................................. 17

Chapter Two: Connections ........................................19

Unpacking and Inspection............................................................ 19

Installing in a Rack ........................................................................ 19

Thermal Considerations in Rack Mounting ............................. 19

AC Power Hookup........................................................................... 20

To use the DEQ224 in another country: ................................................20

Connecting Inputs and Outputs .................................................. 21

Connecting to the Channel or Main Inserts of a

mixing console: ................................................................................ 21

Connecting to the inserts on an instrument

amplifier:........................................................................................... 23

About Audio Cables ........................................................................ 24

1

Chapter Three: Basics of Equalization...................25

What is equalization? ..................................................................... 25

Description of the Controls .......................................................... 26

Description of the Basic Modes ................................................... 27

Basic operation: Program mode .................................................. 29

Basic operation: Edit mode........................................................... 30

Basic operation: Store mode......................................................... 36

Channel Copy.............................................................................................. 37

Table Of Contents

Basic operation: Channel Level mode........................................ 38

The "Hidden" Modes........................................................................ 39

Button combinations.................................................................................. 42

Equalization Artifacts.................................................................... 43

Constant Q vs. Variable Q ............................................................. 44

Chapter Four: Applications.......................................49

Chapter Five: Program Charts .................................51

Chapter Six: Troubleshooting................................... 59

Restoring the Factory Programs & Defaults............................ 59

Line Conditioners and Protectors .............................................. 59

Care and Maintenance................................................................... 59

Troubleshooting Index .............................................................................. 60

Specifications................................................................63

Audio Input ................................................................................................. 63

Audio Output..............................................................................................63

Audio Performance .................................................................................... 63

Mechanical: .................................................................................................. 63

Warranty/Contact Alesis ............................................65

Alesis Limited Warranty.............................................................................65

Alesis Contact Information....................................................................... 66

2

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Introduction

Welcome!

Thank you for purchasing the Alesis DEQ224™. It is a versatile
product, and whether it becomes a part of your studio or finds its
place in your live setup, we know it will serve you well. Since 1984,
we've been designing and building creative tools for the audio
community. We believe in our products, because we've heard the
results that creative people like you achieve with them.

One of Alesis' goals is to make high-quality music technology
available to everyone. This Reference Manual is an important part
of that, because in it we try to present the DEQ224’s features in a
way that is easy to understand and remember. But even beyond
explaining each feature and parameter, this manual can be the key
that unlocks an application for the DEQ224 that you may not have
considered. So we try to write our manuals as carefully as we build
our products.

The goal of this manual is to get you the information you need as
quickly as possible, with a minimum of hassle. We hope we've
achieved that. If not, please drop us an email and give us your
suggestions on how we could improve future editions of this
manual.

We hope your investment will bring you many years of creative
enjoyment and help you achieve your goals.

Sincerely,
The people of Alesis

or more effective

ervice and product

update notices, please

egister your DEQ224

nline at:

ttp://www.alesis.com/

upport/warranty.htm

3

Introduction

DEQ224 Key Features

1. Designed to offer the best of digital technology and analog­style control: the immediacy of a graphic display with
instantaneous editing of any band or combination of bands, as
well as the ability to store your own programs

2. 60 programs total: 30 preset and 30 user-programmable

3. 48 KHz sampling rate

4. 24-bit A/D and D/A with 28-bit internal processing

5. Two channels of equalization

6. 24 EQ bands per channel, spanning 25 Hz-19 kHz

7. +/- 12 dB boost/cut with center detent

8. Constant Q technology allows finer control between bands
than conventional graphic equalizers

9. LOCK function allows the DEQ224 to be used in "set and
forget" situations, such as control room tuning, main live
mixes, monitor mixes, etc., without fear of accidental
reprogramming

10. Individual Channel Level adjustment per program

11. Master Level adjustment

12. [CHANNEL] button for switching quickly between

Channels A and B, for editing and viewing of EQ curves

13. LINK mode, accessed by [CHANNEL] button, allowing

quick creation of matched EQ curves

14. [BYPASS] button

15. Configurable editing mode to suit the way you work

16. Several methods of accelerated program selection

17. Ability to copy settings from Channel A to Channel B during

Store procedure

18. Instant reset of parameter/gain values with a simultaneous

press of the [DOWN/UP] buttons

19. Easy-to-read 7-segment Numeric LED Display

20. Over 300 Band Gain LEDs, making it easy to read EQ curves

from a distance

21. SIGNAL and CLIP LEDs

22. Balanced input/impedance-balanced output (TRS)

23. Compact 1/2-rack profile

For full operating specifications, see page 63.

4

Introduction

H

How to Use This Manual

This manual is divided into the following sections describing the
various functions of and applications for the DEQ224. While it's a
good idea to read through the entire manual once carefully, those
having general knowledge about audio equipment should use the
table of contents to look up specific functions.

Chapter 1: Quick Start Guide. If you're already familiar with
equalization, this will get you started using the DEQ224 right away.
It's a short guide to the essential elements of hooking it up and
using it for the first time.

Chapter 2: Connections. This section gives detailed instructions for
connecting the DEQ224 to a variety of typical audio systems.

Chapter 3: Basics of Equalization. This section explains what an
equalizer does and explains the function of each of the controls.

Chapter 4: Applications. Skip to this section for tips on using the
DEQ224 in a variety of settings.

Chapter 5: Program Charts. Here you will find the names for all 60
Factory Programs, with a brief description of each and a small
graphic representation of the front panel settings.

Chapter 6: Troubleshooting. Near the end of the manual you will find
troubleshooting tips and a complete list of the DEQ224’s
specifications.

elpful tips and advice are
highlighted in a shaded box
like this.

The names of specific buttons
on the DEQ224 are printed in
a bold font and bracketed:
i.e., the [BYPASS] button.

When something important
appears in the manual, an
exclamation mark (like the
one shown at left) will appear
with some explanatory text.
This symbol indicates that
this information is vital when
operating the DEQ224.

5

Introduction

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6

Important Safety

Instructions

Important Safety Instructions (English)

Safety symbols used in this product

operating and maintenance instructions in the literature
accompanying this unit.

the unit that can cause dangerous electric shocks.

voltages that can cause dangerous electrical shock.

Please follow these precautions when using
this product:

1. Read these instructions.

2. Keep these instructions.

3. Heed all warnings.

4. Follow all instructions.

5. Do not use this apparatus near water.

6. Clean only with a damp cloth. Do not spray any liquid cleaner

7. Install in accordance with the manufacturer's instructions.

8. Do not install near any heat sources such as radiators, heat

9. Do not defeat the safety purpose of the polarized or

10. Protect the power cord from being walked on or pinched,

11. Use only attachments or accessories specified by the

This symbol alerts the user that there are important

This symbol warns the user of uninsulated voltage within

This symbol warns the user that output connectors contain

onto the faceplate, as this may damage the front panel controls
or cause a dangerous condition.

registers, stoves, or other apparatus (including amplifiers) that
produce heat.

grounding-type plug. A polarized plug has two blades with
one wider than the other. A grounding-type plug has two
blades and a third grounding prong. The wide blade or the
third prong are provided for your safety. When the provided
plug does not fit into your outlet, consult an electrician for
replacement of the obsolete outlet.

particularly at plugs, convenience receptacles, and the point
where they exit from the apparatus.

manufacturer.

Continued next page

7

Important Safety Instructions

12. Use only with a cart, stand, bracket, or table designed for use
with professional audio or music equipment. In any
installation, make sure that injury or damage will not result
from cables pulling on the apparatus and its mounting. If a
cart is used, use caution when moving the cart/apparatus
combination to avoid injury from tip-over.

13. Unplug this apparatus during lightning storms or when unused
for long periods of time.

14. Refer all servicing to qualified service personnel. Servicing is
required when the apparatus has been damaged in any way,
such as when the power-supply cord or plug is damaged, liquid
has been spilled or objects have fallen into the apparatus, the
apparatus has been exposed to rain or moisture, does not
operate normally, or has been dropped.

15. This unit produces heat when operated normally. Operate in a
well-ventilated area with at least six inches of clearance from
peripheral equipment.

16. This product, in combination with an amplifier and
headphones or speakers, may be capable of producing sound
levels that could cause permanent hearing loss. Do not
operate for a long period of time at a high volume level or at a
level that is uncomfortable. If you experience any hearing loss
or ringing in the ears, you should consult an audiologist.

17. Do not expose the apparatus to dripping or splashing. Do not
place objects filled with liquids (flower vases, soft drink cans,
coffee cups) on the apparatus.

18. WARNING: To reduce the risk of fire or electric shock, do
not expose this apparatus to rain or moisture.

8

Important Safety Instructions

Instructions de Sécurité Importantes (French)

Symboles utilisés dans ce produit

Ce symbole alèrte l’utilisateur qu’il existe des instructions
de fonctionnement et de maintenance dans la documentation
jointe avec ce produit.

Ce symbole avertit l’utilisateur de la présence d’une
tension non isolée à l’intérieur de l’appareil pouvant engendrer des
chocs électriques.

Ce symbole prévient l'utilisateur de la présence de tensions
sur les raccordements de sorties, représentant un risque
d'électrocution.

Veuillez suivre ces précautions lors de
l’utilisation de l’appareil:

1. Lisez ces instructions.

2. Gardez ces instructions.

3. Tenez compte de tous les avertissements.

4. Suivez toutes les instructions.

5. N’utilisez pas cet allareil à proximité de l’eau.

6. Ne nettoyez qu’avec un chiffon humide. Il est potentiellement

dangereux d'utiliser des pulvérisateurs ou nettoyants liquides
sur cet appareil.

7. Installez selon les recommandations du constructeur.

8. Ne pas installer à proximilé de sources de chaleur comme

radiateurs, cuisinière ou autre appareils (don’t les
amplificateurs) produisant de la chaleur.

9. Ne pas enlever la prise de terre du cordon secteur. Une prise

murale avec terre deux broches et une troisièrme reliée à la
terre. Cette dernière est présente pour votre sécurité. Si le
cordon secteur ne rentre pas dans la prise de courant,
demandez à un électricien qualifié de remplacer la prise.

10. Evitez de marcher sur le cordon secteur ou de le pincer, en

particulier au niveau de la prise, et aux endroits où il sor de
l’appareil.

11. N’utilisez que des accessoires spécifiés par le constructeur.

Suite de la page suivante

9

Important Safety Instructions

12. N’utilisez qu’avec un stand, ou table conçus pour l’utilisation

d’audio professionnel ou instruments de musique. Dans toute
installation, veillez de ne rien endommager à cause de câbles
qui tirent sur des appareils et leur support.

13. Débranchez l’appareil lors d’un orage ou lorsqu’il n’est pas

utilisé pendant longtemps.

14. Faites réparer par un personnel qualifié. Une réparation est

nécessaire lorsque l’appareil a été endommagé de quelque sorte
que ce soit, par exemple losrque le cordon secteur ou la prise
sont endommagés, si du liquide a coulé ou des objets se sont
introduits dans l’appareil, si celui-ci a été exposé à la pluie ou à
l’humidité, ne fonctionne pas normalement ou est tombé.

15. Puisque son fonctionement normale génère de la chaleur,

placez cet appareil au moins 15cm. des équipments
péripheriques et assurez que l’emplacement permet la
circulation de l’air.

16. Ce produit, utilisé avec un amplificateur et un casque ou des

enceintes, est capable de produite des niveaux sonores pouvant
engendrer une perte permanente de l’ouïe. Ne l’utilisez pas
pendant longtemps à un niveau sonore élevé ou à un niveau
non confortable. Si vous remarquez une perte de l’ouïe ou un
bourdonnement dans les oreilles, consultez un spécialiste.

17. N'exposez pas l'appareil à l'égoutture ou à l'éclaboussement.

Ne placez pas les objets remplis de liquides (vases à fleur,
boîtes de boisson non alcoolique, tasses de café) sur l'appareil.

18. AVERTISSEMENT: Pour réduire le risque du feu ou de

décharge électrique, n'exposez pas cet appareil à la pluie ou à
l'humidité.

10

Important Safety Instructions

Lesen Sie bitte die folgende Sicherheitshinweise (German)

Sicherheit Symbole verwendet in diesem
Produkt

Dieses Symbol alarmiert den Benutzer, daß es wichtige
Funktionieren und Wartung Anweisungen in der Literatur gibt, die
diese Maßeinheit begleitet.

Dieses Symbol warnt den Benutzer der nicht isolierten
Spannung innerhalb der Maßeinheit, die gefährliche elektrische
Schläge verursachen kann.

Dieses Symbol warnt den Benutzer, dem Ausgabestecker
Spannungen enthalten, die gefährlichen elektrischen Schlag
verursachen können.

Folgen Sie bitte diesen Vorkehrungen, wenn
dieses Produkt verwendet wird:

1. Lesen Sie die Hinweise.

2. Halten Sie sich an die Anleitung.

3. Beachten Sie alle Warnungen.

4. Beachten Sie alle Hinweise.

5. Bringen Sie das Gerät nie mit Wasser in Berührung.

6. Verwenden Sie zur Reinigung nur ein weiches Tuch.

Verwenden Sie keine flüssigen Reinigungsmittel. Dies kann
gefährliche Folgen haben.

7. Halten Sie sich beim Aufbau des Gerätes an die Angaben des

Herstellers.

8. Stellen Sie das Gerät nich in der Nähe von Heizkörpern,

Heizungsklappen oder anderen Wärmequellen (einschließlich
Verstärkern) auf.

9. Verfehlen Sie nicht den Zweck des grounging Terminals auf

dem Netzstecker. Dieses Terminal wird für Ihre Sicherheit zur
Verfügung gestellt.

10. Verlegen Sie das Netzkabel des Gerätes niemals so, daß man

darüber stolpern kann oder daß es gequetscht wird.

11. Benutzen Sie nur das vom Hersteller empfohlene Zubehör.

Fortsetzung auf nächster seite

11

Important Safety Instructions

12. Verwenden Sie ausschließlich Wagen, Ständer, oder Tische, die

speziell für professionelle Audio- und Musikinstrumente
geeignet sind. Achten Sie immer darauf, daß die jeweiligen
Geräte sicher installiert sind, um Schäden und Verletzungen zu
vermeiden. Wenn Sie einen Rollwagen benutzen, achten Sie
darauf, das dieser nicht umkippt, um Verletzungen
auszuschließen.

13. Ziehen Sie während eines Gewitters oder wenn Sie das Gerät

über einen längeren Zeitraum nicht benutzen den Netzstecher
aus der Steckdose.

14. Die Wartung sollte nur durch qualifiziertes Fachpersonal

erfolgen. Die Wartung wird notwendig, wenn das Gerät
beschädigt wurde oder aber das Stromkabel oder der Stecker,
Gegenstände oder Flüssigkeit in das Gerät gelangt sind, das
Gerät dem Regen oder Feuchtigkeit ausgesetzt war und
deshalb nicht mehr normal arbeitet oder heruntergefallen ist.

15. Dieses Gerät produziert auch im normalen Betrieb Wärme.

Achten Sie deshalb auf ausreichende Lüftung mit mindestens
15 cm Abstand von anderen Geräten.

16. Dieses Produkt kann in Verbindung mit einem Verstärker und

Kopfhörern oder Lautsprechern Lautstärkepegel erzeugen, die
anhaltende Gehörschäden verursachen. Betreiben Sie es nicht
über längere Zeit mit hoher Lautstärke oder einem Pegel, der
Ihnen unangenehm is. Wenn Sie ein Nachlassen des Gehörs
oder ein Klingeln in den Ohren feststellen, sollten Sie einen
Ohrenarzt aufsuchen.

17. Setzen Sie den Apparat nicht Bratenfett oder dem Spritzen

aus. Plazieren Sie die Nachrichten, die mit Flüssigkeiten
(gefüllt werden Blumevases, Getränkdosen, Kaffeetassen)
nicht auf den Apparat.

18. WARNING: um die Gefahr des Feuers oder des elektrischen

Schlages zu verringern, setzen Sie diesen Apparat nicht Regen
oder Feuchtigkeit aus.

12

Important Safety Instructions

CE Declaration Of Conformity

See our website at:

http://www.alesis.com

FCC Compliance Statement

This device complies with Part 15 of the FCC rules. Operation is
subject to the following two conditions: (1) This device may not
cause harmful interference and (2) this device must accept any
interference received, including interference that may cause
undesired operation.

NOTE: This equipment has been tested and found to comply with
the limits for a Class B digital device, pursuant to Part 15 of the
FCC Rules. These limits are designed to provide reasonable
protection against harmful interference in a residential installation.
This equipment generates, uses and can radiate radio frequency
energy and, if not installed and used in accordance with the
instructions, may cause harmful interference to radio
communications. However, there is no guarantee that interference
will not occur in a particular installation. If this equipment does
cause harmful interference to radio or television reception, which
can be determined by turning the equipment off and on, the user
is encouraged to try to correct the interference by one or more of
the following measures:

-- Reorient or relocate the receiving antenna.

-- Increase the separation between the equipment and receiver.

-- Connect the equipment into an outlet on a circuit different from
that to which the receiver is connected.

-- Consult the dealer or an experienced radio/TV technician for
help.

13

Important Safety Instructions

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14

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1 Quick Start Guide

If you can't wait to get started

The Alesis DEQ224™ is a unique product, but its basic hookup
and operation are similar to other equalizers in most respects. If
you're experienced with signal processors, this chapter is a
“shorthand” guide for those who want to start using the DEQ224
right away. If you have questions about any of the features, don’t
worry – we’ll cover everything in greater detail in later chapters.

Step 1: Hook it up to a mixer

1. Plug the POWER jack on the back of the DEQ224 into a

grounded AC power source with the supplied power adapter.

2. Using a pair of high-quality cables, plug the left and right main

outputs of a non-powered mixer into the CHAN A and
CHAN B INPUTs on the back of the DEQ224.

3. Connect another pair of cables to the CHAN A and CHAN

B OUTPUTs of the DEQ224 and plug them into your
amplification system or a pair of powered monitors.

4. Press the [POWER] switch on the front of the DEQ224 to

power up the unit.

5. To simplify your first editing experience, you may want to

link Channel A to Channel B. If both of the LINK A/B
LEDs are lit, this indicates that the channels are linked
already. If one of them is not lit, you may want to press
the [CHANNEL/EXIT] button on the front of the
DEQ224 once or twice until both LEDs are lit. That way
you’ll hear the changes you make to Channel A affect both
channels of audio at once.

f you're new to signal

rocessing, start with the more
detailed instructions for
hookup and operation found in
the next cha

The DEQ224’s power will turn
on automatically once its AC
adapter is plugged in, so be
sure to press the [POWER]
switch to turn the unit off while

ou’re connecting it to your

other equipment.

When connecting the DEQ224
to other equipment, make sure
all gear has been turned off.

lso, to protect your speakers,
be certain your amplifier(s)
are turned all the way down
before turning your equipment
back on.

ter.

15

1 Quick Start Guide

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Step 2: Try some equalization

Play some signal into the unit

While learning the unit, you should play a CD or a multitrack
source into the equalizer. Choose a song or musical passage with a
fairly consistent level, so you can take your time experimenting
with the different features.

1. Put the mixer’s main faders all the way down so you don’t
distort the unit by sending it too much signal.

2. Select program 00 on the DEQ224. The fastest way to do this
is to press the [DOWN] and [UP] buttons at the same time.
This will call up a program with all frequencies set to 0 dB,
which will allow you to hear the changes you make to the
audio more easily.

3. Begin playing your source material. Bring the mixer’s main
faders up gradually until the green LED over the words

SIGNAL A and SIGNAL B begin to light up. Carefully increase

the mixer’s output level until the green LEDs are lit most of
the time. If the red LEDs light up at all, back the mixer’s
output level down until they stop lighting up. This is
important, because the red LEDs indicate that the signal is
clipping on that channel.

4. Press one of the [BAND SELECT] buttons to select a
frequency. One of the LEDs above that button will begin to
blink.

5. Use the [DOWN] and [UP] buttons on either side of the
[POWER] switch to decrease or increase the chosen
frequency. If desired, select another frequency and repeat this
process.

6. Press the [BYPASS] button to hear the signal without the
equalization effect. Press it again to return to the EQ’d signal.

Step 3: Try a filtering effect

The answering machine

A popular vocal effect is to filter the voice to a limited frequency
range. This “telephone” effect is also called “futzing,” and can be
used on any instrument or mix. Here’s how to get that sound on
the DEQ224:

1. Follow the instructions for items 1 and 2 from Step 2.

2. Press all of the [BAND SELECT] buttons in the ranges
from 25 Hz to 607 Hz and from 6.1 kHz to 19 kHz on the
channel you are using.

emember: if one or both of the
red LEDs light up, that means
the signal is clipping. To

revent this, reduce the level
being sent to the proper
channel.

16

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3. Use the [DOWN] BUTTON to reduce all of these
frequencies until their LEDs are at -12 dB.

4. Select all of the unedited frequencies and boost them as high
as you can without clipping the signal.

5. Be sure to toggle the [BYPASS] button to compare the result
with the original.

Quick Start Guide 1

Step 4: Store the Program

Once you have created an interesting program, you can save it to
one of the 30 User program locations. Here’s how to do this:

1. Press the [STORE] button to enter Store mode.

2. Use the [DOWN/UP] buttons to select the new location for
the edited program. For your convenience, programs 51-59
have been left “blank” so you can store your editing
experiments somewhere without fear of overwriting a
program you might want to use later.

3. Press the [STORE] button again to store the program to the
new location.

For a detailed explanation on how to use this mode, see page 36.

rograms 51-59 have been left
“blank” so you have
somewhere to store your

rograms right away.

17

1 Quick Start Guide

18

2 Connections

Unpacking and Inspection

Your DEQ224 was packed carefully at the factory. The shipping
carton was designed to protect the unit during transit. Please keep
this carton in the highly unlikely event that you need to return the
DEQ224 for servicing.

The shipping carton should contain the following items:

• DEQ224 with the same serial number as shown on shipping
carton

• A/C power supply adapter

• 4 Rubber Feet

• This instruction manual

Installing in a Rack

The DEQ224 may be simply set on a table, or you can use a
universal rack adapter to install one or two units in a standard 19"
audio equipment rack. There are many companies that make rack
adapters or rack utility shelves. A couple of examples would be
the UTR1 Half Rack Shelf by Middle Atlantic and the UNS-1
Universal Shelf by Raxxess.

Thermal Considerations in Rack
Mounting

The DEQ224 can be mounted in an equipment rack (occupying
one rack space) or placed on a table or shelf. When you install it,
keep in mind that heat is the greatest enemy of electronic
equipment. Please observe the following:

• The DEQ224 is designed to perform properly over a range of
ambient temperatures from 10° C to +40° C (50° F to 104° F),
in up to 80% non-condensing humidity. These are not absolute
limits, but Alesis cannot guarantee that the DEQ224 will meet
its published specs or remain reliable if operated outside of
these ranges.

• Always allow adequate ventilation behind the DEQ224. Do not
seal any enclosure that holds this unit. It is not necessary to
leave an empty rack space above or below the DEQ224.
However, if your environment is unusually warm and not air
conditioned, space between units will help the units run cooler.

19

2 Connections

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AC Power Hookup

The DEQ224 works with any standard line voltage from 100 to
240 volts as long as the appropriate detachable power supply
adapter is used. The DEQ224 has been shipped with the suitable
adapter for the line voltage in your area.

Plug the "barrel" end of an approved power supply adapter into
the DEQ224’s POWER 9V AC jack and the transformer end into
a good quality, noise-free AC power source of the proper rating.

To use the DEQ224 in another country:

Your DEQ224 was supplied with the correct power supply adapter
for your country or local area. If you plan to travel with it to
another country, obtain an Alesis AC power supply adapter
compatible with the outlets used in the other country and use it in
place of the supplied adapter. These can be obtained through your
Alesis dealer or through the Alesis Parts department.

The DEQ224 is specifically
designed to be powered by
the power supply adapter we
have included. Do not
substitute any other type of

ower supply adapter. If a
replacement is needed, one
may be purchased from your

lesis dealer or from the
lesis Parts departmen

.

20

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Connections 2

Connecting Inputs and Outputs

Connecting to the Channel or Main Inserts
of a mixing console:

Unbalanced I/O

Most mixing consoles have insert jacks near the main outputs and
for each channel as well. These are typically Tip-Ring-Sleeve (TRS)
jacks with the send and return on the same jack. To use the
DEQ224 as an effects insert device, you will need an insert cable
(not included).

When connecting audio
cables and/or turning power
on and off, please make sure
that your amplifiers are
turned off or down to prevent
damage to your speakers.

This cable splits the TRS insert jack into two unbalanced mono
connectors. Usually, the tip is wired to the "Send" connector,
which plugs into one INPUT of the equalizer, and the ring is
wired to the "Return" connector, which plugs into the
corresponding OUTPUT of the equalizer. However, the wiring
of the insert jacks is different on some recording consoles, which
means that the input/output relationship may be reversed. Check
your mixer’s Reference Manual to be sure, or just try it both ways –
this won’t damage the DEQ224.

f your mixer does not have
insert jacks available at its
main outputs, simply connect
the main outputs of your non-

owered mixer to the inputs
of the DEQ224, then connect
the outputs of the equalizer to
the inputs of your mixdown
recorder or amplified
monitoring system.

21

2 Connections

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Mono connections

This example shows how to connect the DEQ224 to one mono
source. You can use this method to connect two mono sources or
one stereo source to the DEQ224. You would need two insert
cables to make both of these connections.

Stereo connections

Use two insert cables to connect the DEQ224 to the main L/R
bus in the same way you would connect it to a pair of channel
inserts. Simply connect one insert cable to the left main insert of
the mixer, and connect the two mono jacks to the CHAN A
INPUT and OUTPUT of the DEQ224. Use another insert cable
to connect the right main insert to the CHAN B INPUT and
OUTPUT of the DEQ224.

You can also simply connect the balanced main outputs of the
mixer to the inputs of the DEQ224, then connect the outputs of
the equalizer to the inputs of your mixdown recorder, monitor
system, etc.

Balanced I/O

Some recording consoles have separate balanced jacks for the
sends and returns instead of a single TRS jack. If your recording
console has these connections, use a balanced TRS cable to
connect the insert send to the INPUT of the equalizer, and
another balanced TRS cable to connect the equalizer OUTPUT to
the insert return.

Operating Levels

The DEQ224 is a “line level” device, which means that it operates
at a nominal level of –10dBV, with a maximum input level of
+5dBV. Some equipment operates at a nominal level of +4dBU,
and can run the signal up to +24dBU. To prevent clipping, reduce
the level being sent from this equipment.

If you are unsure about the nominal operating level of the
equipment to which you will be connecting the DEQ224, refer to
the Reference Manual for that equipment.

Since the DEQ224 has two
channels, A and B, you can
connect two independent
sources. Try using channel

to EQ the rhythm guitar
and channel B to EQ the
bass guitar. Or use channel

on the kick drum and
channel B for the snare
drum.

ever place the equalizer

between the power amp and
the speakers, as the high-

owered levels created by
the power amp will damage
the DEQ224.

odern production values
sometimes lead to the heavy
use of compression during
the mastering process. When

rocessing CD audio, you
may find it necessary at
times to lower the Channel

evel of the active program
so as to avoid clipping the
output stage of the DEQ224.
This will allow additional
headroom for more
extensive equalization. See

g. 38 for details on the
Channel Level function.

22

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Connections 2

Connecting to the inserts on an instrument
amplifier:

Unbalanced I/O

The insert sends on a guitar or bass amp are usually labeled
"effects send and return" or "insert send and return." This allows
your instrument to be boosted to line level before the signal is sent
to the equalizer, processed, and returned to the power amp.

Another method would be to insert the DEQ224 between the
preamp and the power amp, if you are using a two-piece system.
You should never put the equalizer between the power amp and
the speaker, as the high-powered levels created by the power amp
will damage the unit.

Connecting to equipment with XLR inputs and
outputs:

If you are connecting the DEQ224 to a product with XLR
balanced inputs and outputs, you will need to convert this signal to
a TRS balanced connector. Make sure that Pin 2 of the XLR
connector is connected to the Tip of the TRS adapter, and Pin 3 is
connected to the Sleeve.

on't use line transformers!

any XLR-to-1/4" adapters

sold at electronics stores are

OT adapters, but
transformers (and very low
quality transformers at that).

on't use these on the output
of the DEQ224—they're
unnecessary and generally
sound awful because they
don't have the headroom to
handle the DEQ224's output.
Get a hard-wired adapter or
cable from your professional
audio dealer, or make one

ourself from components.

23

2 Connections

About Audio Cables

The connections between the DEQ224 and your studio are your
music’s lifeline, so use only high quality cables. These should be
low-capacitance shielded cables with a stranded (not solid) internal
conductor and a low-resistance shield. Although quality cables cost
more, they do make a difference.

Route cables to the DEQ224 correctly by
observing the following precautions:

• Do not bundle audio cables with AC power cords.

• Avoid running audio cables near sources of electromagnetic
interference such as transformers, monitors, computers, etc.

• Do not place cables where they can be stepped on. Stepping on
a cable may not cause immediate damage, but it can compress
the insulation between the center conductor and shield,
degrading the cable’s performance, or reduce the cable’s
reliability.

• Avoid twisting the cable or having it make sharp, right angle
turns.

• Never unplug a cable by pulling on the wire itself. Always
unplug by grasping the body of the plug firmly and pulling
directly outward.

And most importantly, keep connectors clean. Every few months,
unplug them and wipe off oxidation with a clean cloth soaked in
alcohol or contact cleaner. Insert the plugs in the jacks a few times
to clean the internal jack contacts.

Although Alesis does not endorse any specific product, chemicals
such as Tweek (also known as Stabilant) and Cramolin, when
applied to electrical connectors, are claimed to improve the
electrical contact between connectors.

24

3 Basics of Equalization

This section will explain how equalization works, and explain the
functions of the DEQ224’s controls.

What is equalization?

An equalizer boosts or cuts a frequency range. The DEQ224 is a
graphic equalizer, which means it has many fixed frequency bands
that can be cut or boosted. The term "graphic" is appropriate
because the combined settings of the bands often resemble a
curve, or a "graph." Thus it is often possible to know what the unit
is doing to the sound simply by looking at it from a distance. The
other type of equalizer, a parametric equalizer, can sweep the
frequency bands and adjust the frequency range affected by the cut
or boost of each band. Alesis sells a parametric equalizer called the
PEQ-450.

The most basic level of control on a graphic equalizer is the gain
setting for a band. Each of the bands represents a pre-determined
frequency range, and its gain setting controls the amount of boost
or cut for that frequency range. A setting of 0 dB means that the
signal will not be affected in the area of those audio frequencies.

Depending on the program material, boosting or cutting just one
frequency can have a significant impact on the sound. When all of
the frequency bands are being modified, the impact can be huge.

Equalization is used for:

• Adjusting the timbre of an instrument, voice, mix or effect

• Cutting or boosting frequencies to make a source easier to mix
with other tracks

• Compensating for a less-than-ideal recording

• Compensating for less-than-ideal control room or auditorium
acoustics

• Creating a filter effect

• Eliminating buzz, noise or hum

Equalizers can make your recorded tracks sound polished and
professional. Chapter 5 will describe some specific settings for
various instruments and applications.

25

3 Basics of Equalization

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Description of the Controls

There are twenty-four channel buttons on the DEQ224. These are
the [BAND SELECT] buttons. Above each button is a number
like "25" or "19k." These stand for the audio frequencies,
measured in Hertz (Hz), which are selected for editing by pressing
the [BAND SELECT] buttons below them.

Situated just right of the [BAND SELECT] buttons you will find
three larger buttons. The one in the very middle is the [POWER]
button. On either side of that are the [DOWN] and [UP]
buttons, which are used to edit the gain amount of the frequency
you have selected with the [BAND SELECT] buttons. (It is also
possible to select and edit several frequencies at once; more about
this later.) The [DOWN/UP] buttons are also used to select
programs in Program mode.

Directly above these three buttons are three more buttons: the
[BYPASS], [STORE], and [CHANNEL/EXIT] buttons. Their
functions are as follows:

[BYPASS]

When this button is first pressed, a red LED will light. This means
the DEQ224 is in Bypass mode. As long as this LED is lit,
incoming audio will pass through the unit without being affected
by the DEQ224. This is useful for comparing the "equalized"
signal with the original signal so you can decide if you like the edit
you made. Press the button again to get out of Bypass mode and
hear the effect.

[STORE]

Once you have made an edit you would like to keep, press this
button to enter Store mode. From there you can decide which
of the 30 User locations will become the new home for the
edited Program. You can also copy the settings from Channel A
to Channel B as you store a program. For more information on
this function, see page 36.

[CHANNEL/EXIT]

This button serves a dual purpose:

1. While in Program mode, pressing this button will cycle the

DEQ224 through 3 modes. You can select Channel A,
Channel B or you can Link A and B together which will cause
the settings for Channel B to "mirror" the settings for Channel
A. This is useful for quickly setting up a program without
having to make independent adjustments for each channel.

2. If you’re in the middle of some other activity, such as editing

or storing, pressing this button will allow you to "exit" to
Program mode.

ypass mode “hides” the

effect the EQ and Channel

evel controls have on the

audio. However, the Master

evel function from Setup

mode is unaffected by the

BYPASS] button. For more

information about the
relationship between Channel

evel and Master Level, see
age 40.

Warning! Storing a program
will overwrite the program
that resides in the chosen
location. Be certain this is
what you want to do before

ressing [STORE] a second

time!

t is possible to copy the
settings from Channel A to
Channel B during the Store

rocess so they are not merely

“mirrored.” See page 37 for

urther details.

26

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Basics of Equalization 3

Description of the Basic Modes

Program Mode

When this manual refers to Program mode, we mean the very top
level of functionality of the DEQ224. Program mode is where you
are when it is possible to use the [DOWN/UP] buttons to select
between the different programs that reside in the unit. In this
mode, you have access to the 30 Preset programs and 30 User
programs.

A Program consists of all of the settings on the front panel, with
the exception of the status of the [BYPASS] button. The things
stored in memory and recalled when you select a program are:

• The gain settings of all 24 bands for both channel A and
channel B

• The status of the [CHANNEL/EXIT] button

• The gain settings for all 24 bands of channel B, even if
Channels A and B are Linked. They are merely "hidden" by
the Link function.

• The individual Channel Level settings for channels A and B

If the DEQ224 has been in some other mode, pushing the
[CHANNEL/EXIT] button will return it to Program mode. If
you see a dot to the right of the Program number LEDs, that
means the program has been edited. Be certain to save any changes
you've made that you would like to keep! To learn how to Store an
edited program, turn to page 36.

Edit mode

While in Program mode, if you push one of the [BAND
SELECT] buttons the unit will enter Edit mode. You can tell you

are in Edit mode when you see one or more of the LEDs above
the [BAND SELECT] buttons blinking. Whichever bands have a
blinking LED are the ones that will be boosted or cut when you
use the [DOWN] and [UP] buttons.

After you have edited a frequency or an Edit Group (a group of
frequencies), if you push the [CHANNEL/EXIT] button you
will be returned to Program mode. If you made any changes, you
will see a dot to the right of the Program number LEDs. But be
certain to save any changes you've made that you would like to
keep! That is where Store mode comes in.

Store mode

Pressing the [STORE] button takes you into Store mode. From
here you can decide which of the 30 User Programs will become
the new location for the edited program. You may also instruct
the DEQ224 to copy the settings from Channel A to Channel B
during the Store process. For information on how to perform
either of these procedures, see page 36.

ressing the [DOWN/UP]

buttons at the same time will
reset the band you have
selected to 0 dB.

Warning! Storing a program
will overwrite the program
that resides in the chosen
location. Be certain this is
what you want to do before

ressing [STORE] a second

time!

27

3 Basics of Equalization

f

Bypass mode

This mode is nearly as simple as it sounds: push the [BYPASS]
button and the DEQ224 will let you hear the non-equalized audio.
But there’s a bit more to it than that. There are also two gain
adjustment stages that can be used to compensate for a reduction
or increase in signal level caused by the equalization curve being
used. The value for one of these stages (Channel Level) is saved
along with the EQ settings when the program is stored; the value
for the other stage (Master Level) is not. So what Bypass mode
really is doing is causing the audio to “pass by” the processing
stages that are stored as a part of the program.

Here is a diagram that shows the relationship of each of the stages
in the DEQ224’s signal processing chain:

Channel Level mode

If you are running two different instruments into channels A and
B, you may be experiencing drastically different signal levels in
each Channel. Channel Level mode allows you to adjust the output
of channels A and B independently.

This mode is also useful when processing a stereo signal. If the
combination of the source material and extreme EQ settings is
causing the output of the DEQ224 to clip, Channel Level mode
allows you to adjust the output of channels A and B
simultaneously.

Unlike the Master Level function in Setup mode, the settings for
Channel Level mode are stored with each program. To learn how
to use this mode, see page 38.

You’ll find a description of
Channel Level mode further
down on this page. For a
description of the Master Level

unction, turn to page 40.

28

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Basics of Equalization 3

Basic operation: Program mode

Program mode is where to be if you want to call up another
program, or if you just want to know the number of the program
you are using. The DEQ224 has 60 programs in all: 30 Preset
programs and 30 User programs. The Preset programs are the
ones numbered 00-29, while the User programs are numbered 30-

59. You can use the Preset programs as starting points for your

own programs, but you cannot store your creations back on top of
a Preset program. That's what the User programs are for.

Navigation in Program mode is a breeze. First, if you're not in
Program mode, get there by pressing the [CHANNEL/EXIT]
button. The large LED readout will show you the number of the
current program. All you have to do to call up a new Program is
press one of the [DOWN/UP] buttons.

If you hold down one of the [DOWN/UP] buttons for a few
seconds, the DEQ224 will begin to race through the programs.
That's one way to get from Program 10 to Program 40 more
quickly, for example. You'll also notice that it doesn't matter
whether you go up or down; you can get from Program 10 to
Program 40 going either direction.

But there's a way to get around Program mode even more quickly.
If you press and hold the [UP] button while you press the
[DOWN] button, the DEQ224 will jump to Program 00. If you
keep pressing the [DOWN] button, the DEQ224 will jump
backward through the programs in increments of 10 (50, 40, 30,
etc.). Likewise, if you press and hold the [DOWN] button while
you press the [UP] button, the DEQ224 will jump to Program 00.
And if you keep pressing the [UP] button, the DEQ224 will jump
forward through the programs in increments of 10 (10, 20, 30,
etc.).

Once you get the hang of those two methods of navigation, you
can reach any program in the unit's memory in two seconds or
less.

ressing the [DOWN/UP]

buttons at the same time
while in Program mode will
call up Program 00, the
default program.

29

3 Basics of Equalization

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Basic operation: Edit mode

If you're not already there, exit to Program mode by using the
[CHANNEL/EXIT] button. Then select program 00 on the
DEQ224 by pressing the [DOWN] and [UP] buttons at the same
time.

Program 00 is a "flat" program, and it's easy to see why it's called
that: the gain setting for every band is 0 dB. Calling up this
program is almost the same as pressing the Bypass button, in that
the audio passing through the unit will not be equalized in any way.
Of course, the difference is that you can edit the program and hear
the changes that you make. If you don't already know what kind
of EQ you're looking for, this may be a good place to start.

Single Band Edit

Pressing a [BAND SELECT] button puts the DEQ224 into Edit
mode. The Numeric LED Display will change from the current
program number to the gain value in decibels (dB) of the band
you just selected. In addition, one of the Band Gain LEDs above
that [BAND SELECT] button will start blinking. If the gain
value of that band is 0 dB, the green LED will blink. This means
there is no gain change occurring in this frequency range. If it is
higher or lower than that, one of the yellow LEDs will blink. This
indicates that some amount of cut or boost is happening.

Use the [DOWN/UP] buttons to change the gain value of that
band. The [DOWN] button will lower the gain value, or "cut" the
chosen frequency; the [UP] button will raise the gain value, or
"boost" the frequency. Pressing both the [DOWN] and [UP]
buttons at the same time will reset the gain value of the frequency
to 0dB. There is an overall range of +/- 12 dB of gain change
available.

Band Solo

The DEQ224 has a handy feature called Band Solo that allows you
to “isolate” a given frequency while you are editing. This can help
you determine exactly which band you need to highlight or de­emphasize. It’s simple to do:

1. Select a band by pressing and holding its [BAND SELECT]

button.

2. Press the [UP] button. You’ll see the LED for that band

jump to +12 dB.

3. Press the [DOWN] button. The LED for that band will

jump to –12 dB.

4. Release the [BAND SELECT] button and the value of that

band will be unchanged.

This only works with one band at a time, but you’ll find it to be a
very helpful feature.

Use Program 00 if you want to
start with a “clean slate” and
build a new program from the
ground up.

fter resetting a band’s value,

ou can change the level of

that band in 2 dB increments if

ou hold one of the

DOWN/UP] buttons and

ress the opposite button
repeatedly. This can help you
set up a curve with greater
accuracy and speed.

30

R

To exit Edit mode, press the [CHANNEL/EXIT] button. This
will return the DEQ224 to Program mode. The same thing will
happen if you de-select the single band you have selected.

Band Gain Cut/Boost Ranges

Whether you are cutting or boosting a band, the first 10 dB of
change happens in 0.5 dB increments. The last 2 dB of change,
going from +/-10 dB to +/-12 dB, happens in increments of 1.0
dB. So as you make the change, the Numeric LED Display will
show you values like this: 0.5, 1.0, 1.5, 2.0, 2.5 ... 9.0, 9.5, 10, 11,

12.

It’s not possible to show a minus sign in the LED display for
negative gain values. So when you're pushing the [DOWN]
button, you'll see the same values: 0.5, 1.0, 1.5, 2.0, 2.5 ... 9.0, 9.5,
10, 11, 12. But if there's any doubt in your mind about which away
you're going, the Band Gain LED will clue you in. As soon as you
move 0.5 dB away from 0, the LED for that band will change from
green to yellow. If you are cutting the frequency, the -2 dB LED
will light. If you are boosting the frequency, the +2 dB LED will
light. And on it goes until you reach the maximum value in either
direction.

The resolution of the gain increments is higher than the number
of gain LEDs in each band on the front panel can fully display.
Therefore, you may make 0.5dB changes to gain and a band's Gain
LED may not change. The following table shows the amount of
change in dB it takes to light each of the Band Gain LEDs:

LED Gain change

+ 12 dB + 12 dB

+ 10 dB 9.5 – 11 dB

+ 8 dB 7.5 - 9.0 dB

+ 6 dB 5.5 - 7.0 dB

+ 4 dB 3.5 - 5.0 dB

+ 2 dB 0.5 - 3.0 dB

0 dB 0 dB

- 2 dB 0.5 - 3.0 dB

- 4 dB 3.5 - 5.0 dB

- 6 dB 5.5 - 7.0 dB

- 8 dB 7.5 - 9.0 dB

- 10 dB 9.5 - 11 dB

- 12 dB - 12 dB

Basics of Equalization 3

emember, if you want to
keep the edited program,
be sure to store it to one of
the User locations. For
instructions on how to do
this, turn to page 36.

31

3 Basics of Equalization

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Multiple Band Edit

Selecting an Edit Group

Pressing a [BAND SELECT] button puts the DEQ224 into Edit
mode. And until you press one of the [DOWN/UP] buttons, you
can keep pressing [BAND SELECT] buttons until you have
several of them selected simultaneously. This is called selecting an
Edit Group. An Edit Group can be made up of any number of
bands from both channels if the Link LED is not active.

The Relative Gain Display

When you pressed the first [BAND SELECT] button, two things
happened: the Numeric LED Display changed to show the gain
value of that band, and one of the corresponding Band Gain
LEDs started to blink. Then when you pressed the second
[BAND SELECT] button, two more things happened: the
Numeric LED Display changed to show the number "0," and a
second Band Gain LED started to blink. Each additional [BAND
SELECT] button you press adds a band and a blinking LED to
the Edit Group.

But why did the Numeric LED Display change to a zero? Because,
once you have selected an Edit Group, you can cut or boost the
gain of all of the bands in the Edit Group at once. They will move
up or down in proportion to one another. The zero in the display
represents a "benchmark" for the amount of gain change that
happens to the Edit Group. The 7-segment LEDs can't display the
gain values of each band within the Edit Group all at once, so if
you raise the overall level of the Edit Group by 2 dB, that's the
number you will see. The function of the display in this case is to
tell you the Relative Gain amount.

For the sake of clarity, when this manual is describing what is
shown in the 7-segment LEDs while changing the overall gain
value of the Edit Group, we will refer to it as the Relative Gain
display.

Here’s an example: let's say you have selected the bands at 4.6k and

6.1k as your Edit Group. The initial gain value for 4.6k is +2 dB
and the gain value for 6.1k is -2 dB. The Relative Gain display at
this point will read "0." If you press the [UP] button four times,
the final value of the Relative Gain display will be a "2." The actual
gain values for 4.6k and 6.1k are now +4 dB and 0 dB, respectively,
which will be indicated by their Band Gain LEDs.

Proportional Gain Memory

It's possible you may see numbers as large as 24 in the Relative
Gain display. This is due to a very powerful aspect of the Relative
Gain feature, and it will require some careful explanation.

Here's another example. Let's say you have two bands selected.
The first band is set to 0 dB, and the second band is set to -12 dB.
The Relative Gain display reads "0." If you press the [UP] button
and keep holding it, you will see that number change from 0 to 12
(see fig. 1 on page 33). But it won't stop at 12; it will keep racing

n Multiple Band Edit mode,

ressing the [DOWN/UP]

buttons at the same time will
reset the Relative Gain

isplay to 0. This resets the
bands within the Edit Group
back to their original values.
From this point you can
change the Relative Gain of
the Edit Group in 2 dB
increments by holding one of
the [DOWN/UP] buttons and

ressing the other one

repeatedly.

For maximum preservation of

idelity of the input signal, the
largest number of bands in a
channel should be set to 0 dB.
For example, if you have more
than half of your bands set to
some cut amount and the
majority of those cut

requencies are at -4 dB, then
select all bands and
compensate by +4 dB.

32

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Basics of Equalization 3

upward until it reaches 24. This is because that's how far the band
that was set to -12 dB had to travel until it hit the "ceiling," or + 12
dB (see fig. 2).

But what about the band that was set to 0 dB originally...was it
boosted to +24 dB? The answer is, "Yes and no." It was, in the
sense that the DEQ224 keeps track of the proportional values of
the bands, even if they exceed the +/-12 dB limit of gain change
for a frequency. But the audible audio gain is limited to +/-12 dB.

The reason the DEQ224 keeps track of the gain relationship
between the bands in the Edit Group is simple. It's so you can
change your mind, pull them back down to values within the +/­12 dB limit, and still have them be the same distance apart!

For example: let's say you decided these frequencies have been

emember, pressing the

DOWN/UP] buttons at the
same time will reset the

elative Gain Display to 0.
From this point you can
change the Relative Gain of
the Edit Group in 2 dB
increments by holding one of
the [DOWN/UP] buttons and

ressing the other one
repeatedly. This can be a real
time-saver if you want to get

rom a Relative Gain value of

+24 to a value of –24!

boosted too much, and you cut them by 12 dB. At this point the
Relative Gain display would read "12," with band one's Gain LED
at +12 dB and band two's Gain LED at 0 dB (as in fig. 1). So far
you haven't really reduced the gain of the first band, because it's
still at +12 dB. You still want to bring it down a bit, so you take
both frequencies down another 3 dB. So now the Relative Gain
display would read "9," with band one's Gain value at +9 dB and

33

3 Basics of Equalization

band two's Gain value at -3 dB. And now you can see that the gain
relationship between the two bands was preserved; they're still 12
dB apart.

One important note, though; Proportional Gain Memory is only
temporary. If you have run one or more bands "past" the +/-12
dB limit and then you exit Edit mode for any reason (such as to
store the program), the gain value of those bands will be
remembered as +/-12 dB (whichever was the value that was last
reached for those bands).

The Limits of Relative Gain

There will be times when the Relative Gain display will not go all
of the way up or down to a value of 24. This is because the
DEQ224 takes into account the gain setting of all of the bands
when an Edit Group is formed. If the highest gain setting of any
band in the Edit Group is + 6 dB, then from there down to -12 dB
is only 18 dB. So this is the largest number you will see in the
Relative Gain display if you run the relative gain value all the way
down (see fig. 3 and 4).

34

R

Likewise, if the lowest gain setting of any band in this same Edit
Group is -4 dB, then the largest number you will see in the Relative
Gain display going all the way up is 16 (see fig. 5).

So if you run the Relative Gain display up and down repeatedly
with this Edit Group, the display will hit the "ceiling" at 16 and
bottom out at 18.

The Release Edit Group function

Once you have changed the value of the Edit Group, the DEQ224
will react one of two ways to further presses of the [BAND
SELECT] buttons. To decide which option suits your working
method or circumstance, experiment with the setting for the
Release Edit Group function in Setup Mode.

If this function is on, the very next [BAND SELECT] button
you press after you have changed the level of the Edit Group will
"release" all of the previously selected bands. The only band that
will be selected is the one you just pressed. You will know this
when it happens, because that's the only Band Gain LED that will
be blinking.

If the Release Edit Group function is off, the next [BAND
SELECT] button you press after you have changed the level of
the Edit Group will simply add that band to the Edit Group.

For a more detailed explanation of the Release Edit Group
function, see pages 39 and 40.

Basics of Equalization 3

emember, if you want to
keep the edited program,
be sure to store it to one of
the User locations. For
instructions on how to do
this, turn to page 36.

35

3 Basics of Equalization

Basic operation: Store mode

Once you have created a program you would like to save, press the
[STORE] button to enter Store mode. This will cause the
Numeric LED Display to blink with the number of the current
program.

If you were on a Preset program while editing, you will not be able
to store the program until you select one of the 30 User program
locations as its destination. To do this, use the [DOWN/UP]
buttons. If you press the [UP] button first, you will see the
Numeric LED Display jump to User program 30, which is the first
available User program location. If you press the [DOWN]
button first, you will see the Numeric LED Display jump to User
program 59, which is the highest-numbered User program location
available. If you were already on a User program when you entered
Store mode, then using the [DOWN/UP] buttons will call up the
next User program.

Once you are in the User program area inside Store mode, pressing
the [DOWN/UP] buttons allows you to choose a program
number between 30-59 as the destination for your edited program.
Pressing and holding one of these buttons will cause the unit to
scroll progressively faster through the available choices. If you're
holding the [DOWN] button, when the unit reaches User
program 30 it will "wrap" around to number 59 and continue
scrolling downward. Pressing and holding the [UP] button will
cause the numbers to scroll in the opposite direction, wrapping
from program 59 to program 30 and continuing upward.

As in Program mode, there's an even faster way to select the
destination program location. If you press and hold the [DOWN]
button and then push the [UP] button, the unit will jump to
Program 30. If you continue pressing the [UP] button, the
DEQ224 will jump forward through the User locations in
increments of 10 (40, 50, 30, 40, 50, etc.). Similarly, if you press
and hold the [UP] button and then push the [DOWN] button,
the unit will jump to Program 30. If you continue pressing the
[DOWN] button, the DEQ224 will jump backward through the
User locations in increments of 10 (50, 40, 30, 50, 40, 30, etc.).

Once you have chosen the location you want, press the [STORE]
button again. This will store the program into the user location
you selected.

Remember, if at any time you decide you do not want to save the
edited program, simply press the [CHANNEL/EXIT] button to
return to Program mode. Your edited program will still be there, as
evidenced by the dot on the right side of the Numeric LED
Display. The “destination” program will not have been
overwritten.

36

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Basics of Equalization 3

Channel Copy

You can use the Link function while editing to help set up identical
curves on both channels. But at some point the curves may need
to diverge slightly (or significantly). Rather than unlinking the
channels and starting all over again on Channel B, we have
included a handy feature called Channel Copy as a subset of Store
mode.

The Channel Copy feature is a real time-saver. It will allow the
settings from Channel A to be stored over whatever settings are in
Channel B, so that after the completion of the Store process there
will be no difference between the settings of Channels A and B for
that program. Then you can begin to diversify the settings of the
channels to match the needs of the incoming audio.

The process is simple, but it is subtly different from the normal
Store procedure. Pay close attention to the following steps:

1. Before storing the program, unlink the channels. That way
you’ll be able to begin editing Channels A and B
independently as soon as you complete step 7.

2. Press and hold the [STORE] button to enter Store mode. The
Numeric LED Display will begin to flash.

3. While holding the [STORE] button, press the
[CHANNEL/EXIT] button. This will cause the Link A
LED to begin flashing also.

4. Release both buttons.

5. Select the location for the new program using the methods
described on the previous page.

6. To abort the Store procedure, press the
[CHANNEL/EXIT] button. The settings for Channel A
will not have been copied over to Channel B.

7. To store the program, press the [STORE] button a second
time. The settings for Channel A will have been duplicated on
Channel B. To confirm this, toggle the
[CHANNEL/EXIT] button. You should see no difference
between the settings of the channels. Even the Channel Level
settings of Channel B should match that of Channel A.

Warning! Copying settings

rom Channel A to Channel B
will overwrite the current
settings for Channel B. Be
certain this is what you want
to do before pressing

STORE] a second time!

37

3 Basics of Equalization

R

M

L

Basic operation: Channel Level mode

Channel Level mode allows you to adjust the output level of
channels A and B independently or simultaneously. Use this
feature to compensate for a reduction or increase of signal level
due to the equalization curve you have selected.

To enter this mode you must start from Program mode. Once you
are there, you can enter Channel Level mode by doing the
following:

• Select Channel A, Channel B, or both channels by using the
[LINK] button

• Press and hold the 15 kHz button and then press the 19 kHz
button, or vice versa

Note: If you press only one Band Gain button, you won't

enter Channel Level mode--you may have entered Band Edit
mode by mistake.

Once the DEQ224 is in Channel Level mode, you will see the
Band Gain LEDs go completely dark except for the ones over the
buttons mentioned in the two steps above.

From this point onward, Channel Level mode operates exactly like
Band Edit mode: the settings for Release Edit Group and Edit
Time Out are in effect.

The only real difference between the way this mode and Edit
mode operate is in the amount of boost that is allowed to occur in
Channel Level mode. The DEQ224 will allow each channel to be
boosted up to +6 dB, with an allowable cut range of -12 dB. If
you want another 6 dB of gain (for a total of 12 dB), you will find
that in the Master Level function in Setup mode. But remember,
the settings for Channel Level mode are stored with each program.
The settings for the Master Level function are not.

To exit Channel Level mode and return to Program mode, deselect
both channels or press the [CHANNEL/EXIT] button.

For information on selecting
an Edit Group, see page 32.
For information on the

elease Edit Group function,
see page 40. For information
on the Edit Time Out feature,
see page 41. For information
on the Relative Gain Display,
see page 32. For information
on Proportional Gain

emory, see page 32. For

information on the Master

evel function, see page 40.

38

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Basics of Equalization 3

The "Hidden" Modes

There are several sub-levels of operation that can be accessed by
pressing different button combinations:

Demonstration mode

Sometimes it’s fun to have a lot of little lights flashing from the
stage or in the studio. The DEQ224 has a special key combination
that will activate a “light show” for the entertainment of your
clients, audience, or children. To begin the pyrotechnics, first make
sure you are in Program mode. Once you are, hold down the
[CHANNEL/EXIT] button and press the [UP] button.

To exit Demonstration mode, press the [CHANNEL/EXIT]
button.

Setup mode

This is where you will find some of the features that govern the
way the DEQ224 operates in the other modes. They are what you
would call "Global" settings, in that their status is not stored with a
program. No matter which program you call up, these settings will
not change. And since they make such a big difference in how the
unit works, they have been "tucked away" so they won’t be altered
accidentally.

To access Setup mode, first you must turn off the DEQ224. Then
turn the unit back on, wait until you see the letters “DEQ224” in
the display, and then hold down the [STORE] button. After a
couple of seconds you will see the word "SETUP" appear in large
letters above the [BAND SELECT] buttons. Then the LEDs will
read "M LV" and "+00."

The first four [BAND SELECT] buttons are used to select
between the different functions in Setup mode. They are:

Item (button) Function Displayed Options Default

1 (25 Hz) Master Level M L V +/- 6 dB 0 dB

When in Demonstration mode
the DEQ224 will cycle
automatically through all 60

rograms one after the other.
The main difference is that
while in Demonstration
mode, the audio signal is

assed.

b

To return to Program mode

rom Setup mode, press the
CHANNEL/EXIT] button

or turn the DEQ224 off and
back on.

Value

39

2 (34 Hz) Release Edit

3 (45 Hz) Edit Time Out E T O Off/On Off

4 (60 Hz) Lock L C K Off/On Off

Group

R E G Off/On On

Note that as you switch from one function to the next that the
Numeric LED Display will change to show the number of the
selected function.

The [STORE] button may be
used to cycle through the

unctions also.

3 Basics of Equalization

I

Here's a description of what each function does.

Button 1: Master Level (+/- 6 dB)

The Master Level function is one way to customize the DEQ224
to your environment. If the equipment in your setup tends to send
very hot signals, you can use this function to prevent the output of
the DEQ224 from clipping.

When a hot line level signal comes in, the DEQ224 has plenty of
headroom to deal with it. But if you perform some radical
equalization on this signal, it is possible that the combination of
the incoming hot signal plus the equalization you have done may
put the signal "over the top" and within range of clipping. The
Master Level function allows you to reduce the level of the
equalized signal before it reaches the final output stage of the
DEQ224.

Don't confuse this with the Channel Level settings in Edit mode.
The Channel Level settings are stored with the program, and
therefore may vary from program to program. The Master Level
setting is global; i.e., it is always active and will affect every
program. There is a diagram on page 28 that illustrates the
relationship between Channel Level and Master Level.

To lower or raise the Master Level setting, use the [DOWN/UP]
buttons. To reset the value of this function to 0 dB, press the
[DOWN] and [UP] buttons at the same time.

For an explanation of how to use the Channel Level control
feature, see page 38.

Button 2: Release Edit Group (on/off)

Of all the Setup features, this is the one that will most affect the
way you work with the DEQ224. The Release Edit Group setting
determines the behavior of the [BAND SELECT] buttons in
Edit mode.

For the sake of describing this feature, let's review some things we
already know. When you press a [BAND SELECT] button, you
enter Edit mode. If you don't press one of the [DOWN/UP]
buttons right away, you can keep pressing [BAND SELECT]
buttons until you have several of them selected simultaneously.
This is called selecting an Edit Group.

Once you have selected an Edit Group, you can cut or boost the
gain of all of the bands in the Edit Group simultaneously; they
will move up or down in proportion to one another. The Release
Edit Group feature does not affect these things; this is always how
the DEQ224 operates.

However, once you make an edit, it makes a big difference whether
the Release Edit Group feature is on or off. If it is on, the very
next [BAND SELECT] button you press will "release" all of the
previously selected bands. The only band that will be selected is
the one you just pressed. You will know this when it happens,
because that's the only Band Gain LED that will be blinking.

f you are likely to edit only
one or two bands at a time
when constructing a new
curve, set the Release Edit
Group function to On. This
will enable you to move more
quickly across the audio
spectrum.

40

If the Release Edit Group feature is off, the next [BAND
SELECT] button you press after you have changed the level of

the Edit Group will simply add that band to the Edit Group. The
upside of this is the convenience of being able to edit three
frequencies +3 dB, for example, and then add another frequency
to the pile and edit them all another +2 dB without having to
reselect the first three. The downside is that you will have to
deselect all four bands if you want to grab one more frequency
and edit it by itself.

There are pros and cons to both ways of working. So, experiment
with this feature and see which way works best for you.

To enable or disable the Release Edit Group feature from this
Setup mode page, press one of the [DOWN/UP] buttons.

Button 3: Edit Time Out (on/off)

The Edit Time Out function serves as an "auto-exit" feature.
When it is enabled, if you have not changed the gain value of any
band or Edit Group for 30 seconds, the DEQ224 will exit
automatically to Program mode.

We have included this feature so the DEQ224 can mold itself as
seamlessly as possible into your working style. If you prefer not to
have the unit continue reminding you it is still in Edit mode by
blinking its LEDs, vying for your attention, as it were, with the VU
meters on your mixer, then Edit Time Out is a feature you will
appreciate.

On the other hand, if you prefer to have the DEQ224 remain in
Edit mode so you will not lose your chosen Edit Group when the
unit returns to Program mode, you may want to turn the Edit
Time Out function off.

The default setting for this function is "Off"; to enable it press one
of the [DOWN/UP] buttons.

Button 4: Lock (on/off)

This function enables you to choose a particular program as the
only one that can be selected once the DEQ224 is powered on.
After this has been done, pressing any button besides the
[POWER] button will cause the Numeric LED Display to show
“Lo” for “locked.” This is handy for environments in which the
DEQ224 is used for tuning a room, for example, or whenever you
don't want someone calling up a different program, editing the
current program, and/or storing a different program on top of the
one you have created for a particular application.

Before you try this feature, make sure you're happy with the
program you had selected prior to turning the unit off. It will be
the program you are "stuck" with when you turn the unit back on
after enabling the Lock feature.

If you're already in Setup mode, all you have to do to enable this
feature is press the fourth [BAND SELECT] button and then
press one of the [DOWN/UP] buttons. You should see the

Basics of Equalization 3

41

3 Basics of Equalization

LEDs over the Band Gain buttons change from "OFF" to "ON."
Then turn the unit off and on again. Your DEQ224 is now locked.
(No fair using this knowledge to play tricks on your salesperson!)

It's simple to restore the DEQ224 to full functionality (i.e.,
"unlock" it). Just turn the unit off and power it up in Setup mode
again (turn the unit on and press the [STORE] button).
Then press the fourth [BAND SELECT] button and press one
of the [DOWN/UP] buttons to turn this feature off. The next
time you power up the DEQ224 it will operate normally.

Button combinations

Here is a list of the combinations of buttons that are possible in
the DEQ224 and what they do:

Hold: Press: Result

[UP] (First press) Resets

[DOWN]

[UP] (2+ presses) Jumps

[DOWN] (First press) Resets

[UP]

[DOWN] (2+ presses) Jumps

[CHANNEL/EXIT] [UP] Demo mode

[STORE] [CHANNEL/EXIT] Channel

15 k 19 k

“Power up” button combinations

Press & Release Press

[STORE] Setup mode

Power

[DOWN/UP] Reinitialize

value

value

value

value

Copy
Channel

Level

Result

42

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Basics of Equalization 3

Equalization Artifacts

When you apply a lot of EQ (6dB or more), you may hear some
unintended consequences on the output. Here are a few common
side effects to applying a lot of equalization and some ways to
avoid them.

Distortion

If you boost too many frequencies too high, you will distort the
output. If this happens, the red CLIP LED will light. To avoid
this, turn down the signal being sent to the DEQ224. Other
options include adjusting the Channel Level settings in Edit mode,
or adjusting the Master Level setting in Setup mode. The best
option is to try another method of achieving the desired effect: cut
the highs instead of boosting the low frequencies; reduce the lows
and highs instead of boosting the midrange, etc.

Noise

If you boost the high frequencies enough you may hear noise in
your system that was inaudible otherwise. If this is objectionable,
you may want to gate that channel when it isn’t being used or
automate the console so that channel is muted when that
instrument isn’t playing.

Phasing

You may hear some phase distortion if you apply a lot of EQ,
such as boosting 12dB on several bands, for example. This is just
the nature of EQ –the more you cut or boost, the more phase
distortion will occur. Try getting the same effect with less EQ; try
cutting instead of boosting; try a different position for the
microphone. All of these suggestions can help you to achieve the
desired effect with minimal phase distortion.

The potential for artifacts is
highly dependent on the audio
source material. A DEQ224

rogram that works well for

rocessing one source may
clip when processing another
source, depending on which

requencies are present.

aking the program work may
be simply a matter of a slight
adjustment in the gain setting

or one or two bands.

nstruments usually sound

better when you cut the

roblem frequencies instead of
boosting the frequencies you
want to feature.

43

3 Basics of Equalization

Constant Q vs. Variable Q

What makes the DEQ224 unique?

At their inception, graphic equalizers relied solely on a form of
equalization known as "Variable Q." The DEQ224, on the other
hand, is what is known as a "Constant Q" equalizer. This method
of equalization is a relatively recent development in the history of
sound reinforcement and recording technology. As you will see
illustrated in the charts in this section, the Constant Q method
allows for a higher degree of control over the sound being
processed because of its significantly greater accuracy.

Before we go any further, it's time for some definitions:

Q The range of frequencies affected by a

Variable Q A process in which the range of

Constant Q A process in which the range of

It may help to define these terms visually as well.

In the following illustration, we see the three basic terms that
govern the operation of a single band. The vertical bar of the
graph represents decibels of cut/boost, and the horizontal bar
represents frequency in Hz. The dotted line leading to the center
of the curve indicates the frequency at which this band is set. You
can see that in this example, Q covers a range of frequencies from
about 200 Hz to about 5 KHz.

band

frequencies affected by a band changes as the
amount of gain is cut/boosted

Frequencies affected by a band stays the
same as the amount of gain is
cut/boosted

44

In the next illustration, the difference between a narrow Q and a
wide Q is seen:

Varia b le Q

Now we're ready for a visual definition of the term Variable Q. In
the next illustration, the wider and more gradual curve represents a
lower gain setting for a variable Q equalizer. The narrower and
more steep curve represents a higher gain setting at the same
frequency:

The previous illustration has been exaggerated somewhat to make
the point, but you can see how a lower gain setting also boosts
frequencies that overlap to some extent into the regions affected
by the next highest and lowest frequency band controls.

Constant Q

In contrast, a Constant Q equalizer has a more consistent range of
frequencies under its control throughout its cut/boost range, as
illustrated below:

Basics of Equalization 3

45

3 Basics of Equalization

Multi-band application and results

So far we have only dealt with cutting or boosting single frequency
bands. The differences between the constant Q and variable Q
methods become more "graphic," if you will, when adjacent
frequency bands are involved.

In this example, three adjacent bands are used. They have settings
of + 6 dB, 0 dB, and + 6 dB, respectively:

You can see how the 0 dB setting on the variable Q equalizer
merely serves to round off the top of the curve; in actuality, this
translates into a boost in the range of frequencies under that
band's control. You would have to cut the gain on that band
significantly to reduce the unintended consequences of boosting
the other two frequency ranges.

The constant Q equalizer, on the other hand, has more precise
control over each of the frequency bands. As you can see in this
example, the effect on the center band is significantly lower:

46

To further illustrate the differences, here is a pair of examples in
which three adjacent bands have settings of + 3 dB, -3 dB, and + 3
dB, respectively:

Remember that at lower gain settings, there is an even wider Q for
a given frequency band on a variable Q equalizer. The center
frequency band needs to be edited even more drastically in order
for any noticeable reduction of frequencies in its range.

The corresponding illustration for the constant Q equalizer speaks
for itself:

We offer this information regarding the differences between
constant Q and variable Q equalizers not as an attempt to
persuade the world to reject variable Q equalizers out of hand; in
some applications either would do the job nicely. But when a
greater degree of control over the program material is needed, a
constant Q equalizer like the DEQ224 offers a significant
advantage.

Basics of Equalization 3

47

3 Basics of Equalization

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48

4 Applications

This section is designed to get you started with the DEQ224 by
giving some sample settings. These are merely suggested settings;
experiment and find your own once you begin to hear what the
DEQ224 does to your sound.

In a way, it’s absurd to suggest EQ settings without knowing what
the source sounds like. EQ is a tool that’s used to change the
timbre of a sound, and it’s impossible to suggest an EQ setting
that, for example, will make all guitars sound better. So the goal of
this section is to give you some ideas for using EQ on your own
tracks.

Rock Kick Drum

A rock and roll kick drum is usually EQ’d quite a bit to make it
sound the way it does on the radio. Usually an engineer will choose
to cut some of the woofy low-midrange, while boosting the high­end "slap" and maybe even some of the lows. Here is a setting to
try on a close-miked kick drum:

• Select all frequencies below 80Hz and boost 3dB

• Cut 454Hz by 8dB

• Boost all frequencies above 4.6kHz by 4dB

You may also want to apply some compression and gating with the
Alesis CLX-440.

Vocal Air

A popular effect on vocals is to boost the high frequencies to add
"air" to the vocal. This is an especially popular effect on ballads
sung by R&B divas. This effect is achieved by boosting the high
frequencies:

• Boost 15 kHz by 6dB

• Boost 19 kHz by 6dB

Tape Hiss Removal

If a recording has a lot of tape hiss, such as one transferred from
cassette, you can usually get rid of it by dropping the high
frequencies a bit:

• Select all frequencies from 8.2kHz up and cut them by 6dB

Adjust the gain of different bands to compromise between
keeping the high end of the recording and eliminating tape hiss.

49

4 Applications

Eliminating Feedback

During a live performance, you may experience feedback if a
microphone is placed too close to a monitor. However, this
feedback often occurs at one frequency before it happens at
others. You can "ring out" the monitor by using EQ to cut the
frequency that’s feeding back. The following is best to try when the
band and audience are not present:

1. Insert the EQ between the mixer’s monitor output and the
monitor amplifier.

2. Slowly and carefully raise the monitor level to the point of
feedback. Notice that it always feeds back at the same
frequency unless the mic is moved a lot. As soon as you hear
feedback, turn the monitor level down, but not off.

3. Select a band that is near where you think the feedback is
occurring. For example, if you’re getting high-frequency
feedback, try 6.1 kHz.

4. Slowly raise the 6.1 kHz Band Gain level while listening for
feedback. If you hear feedback, cut that frequency because you
guessed right.

5. If you don’t hear feedback, return that band to “0” and repeat
this procedure with another frequency band. Once you hear
feedback, cut that frequency.

If you don’t hear feedback at any frequency using this method, try
boosting the monitor level a little more.

This procedure can be an
effective tool in isolating and
eliminating feedback in the
main or house system as well.

50

5 Program Charts

Note for all program charts

An "L" in the box on the right side of the front panel illustration indicates that a program’s
Link function is active. Programs that are not linked have a different curve for each channel,
so there will be two charts for that program (e.g., 9a “Kick” and 9b “Snare”).

# Title

0 Flat

The DEQ224 will not affect the
signal; the output signal will sound
the same as the input signal.

1 Smile

The smile curve is a time-tested
technique used by live sound
engineers. No time for a sound
check? Start here.

2 Brighten

If you need to give your sound a
little sharpness to cut through...

Front panel

51

3 Warmth

Soften the edginess of your mix
with this program.

4 Darken

This is for the times when subtlety
isn't enough.

5 Speech

This eliminates unexpected
rumbling or mic handling noise and
lends some clarity to the upper end.

6 Loudness Plus

Mimics the “Boost” button on
stereo equipment: a more balanced
sound for low-level listening.

5 Program Charts

7 Techno

This setting emphasizes the
extremes to get the dancing bodies
really moving.

8 Proximity Effect

This curve mimics the aural
phenomenon that the closer a
listener is to a sound source, the
more the bass is emphasized.

Note for programs 9-12

The next four programs have the Link function turned off, so each channel is doing
something different. Each of these programs has two charts listed below, an “a” chart and a
“b” chart.

9a Kick

Link=Off. Feed a kick drum into
Channel A for thump, beater tap,
and to reduce hollowness.

9b Snare

Link=Off. Ch. B reduces low end to
separate the snare and kick and also
reduces hollowness.

52

10a Bass Guitar

Link=Off. General setting for bass
guitar--make adjustments as needed.

10b Acoustic Guitar

Link=Off. Ballpark setting for
acoustic guitar--adjust as needed.

11a Male Vocal

Lows reduced to avoid rumble, high­end emphasized for intelligibility.

11b Female Vocal

Lows reduced to avoid rumble, high­end emphasized for intelligibility.

Program Charts 5

12a Cross-Over

Split a full-range mono signal into
both channels and send Channel A to
an amplifier feeding the woofers.

12b Cross-Over

Split a full-range mono signal into
both channels and send Channel B to
an amplifier feeding the tweeters.

13 Hum Reduction

This will reduce 60Hz hum and its
harmonics without having a large
impact on the sound.

14 Telephone

Use this to make the signal sound as
if it is coming out of a phone.

53

15 Less SSS

This helps reduce sibilance—use it
as a “de-esser.”

Note for programs 16-20 and 22-26

Send the signal you want to equalize through Narrow Boosts 1-5 to find the frequency that
may be most objectionable. Take note of that frequency for further editing or just set the
DEQ224 to the Narrow Cut 1-5 program that matches the Boost program that emphasized
the frequency range in question.

16 Narrow Boost 1 (80Hz)

See note for programs 16-20 and
22-26

5 Program Charts

17 Narrow Boost 2 (255Hz)

See note for programs 16-20 and
22-26

18 Narrow Boost 3 (810Hz)

See note for programs 16-20 and
22-26

19 Narrow Boost 4 (2.6kHz)

See note for programs 16-20 and
22-26

20 Narrow Boost 5 (8.2kHz)

See note for programs 16-20 and
22-26

21 Low Shelf

Eliminates low rumble, leaving
everything else untouched (corner
frequency is approximately 65Hz).

54

22 Narrow Cut 1 (80Hz)

See note for programs 16-20 and
22-26

23 Narrow Cut 2 (255Hz)

See note for programs 16-20 and
22-26

24 Narrow Cut 3 (810Hz)

See note for programs 16-20 and
22-26

25 Narrow Cut 4 (2.6kHz)

See note for programs 16-20 and
22-26

26 Narrow Cut 5 (8.2kHz)

See note for programs 16-20 and
22-26

Program Charts 5

27 High Shelf

Eliminates high end, leaving
everything else untouched (corner
frequency is approximately 8kHz).

Note for programs 28 and 29

These two programs are mirrored. The setting for Channel A on program 28 is the same as the
setting for Channel B on program 29. Likewise, the setting for Channel A on program 29 is
the same as the setting for Channel B on program 28.

28a

29b

Mostly for show, but since Channel A
& B are not linked, there can be some
happy accidents in terms of how
these programs affect your signals.

Sine Wave Pattern I

29a

28b

Sine Wave Pattern II

55

See note for program 28.

Note for programs 30-59

The following 30 programs reside in the User program area. They can be overwritten with
your own programs. (Naturally, if you have done that, the following diagrams no longer
apply.) We suggest that you try these before storing a new program in their place, though;
you might find some of them useful as a starting point for some of your own programs. It is
possible to recall all 30 of these at once (see page 59 for details). But be forewarned: doing
so will erase any programs you have stored.

30 Vinyl Warmth

This mimics the frequency response
of common phono players.

31 Tape Hiss Reduction

This is a way to deal with noisy
source material that originates from
magnetic media.

5 Program Charts

32 Mini TV

If you’re looking for that sound you
get with one of those portable
televisions, try this one.

33 Megaphone Bandlimit

Sounds like what the name implies.

34 Air Boost

Just the opposite of the high shelf
curve.

35 AM Radio

Another band-limiting curve for
using as an effect.

36 R&B Radio

This has the same bass and treble
emphasis often found across
modern R&B radio stations.

37 Acoustic Guitar Air

Try pointing two mics at different
areas of an acoustic guitar and
running it through this program.

38 Electric Guitar Bandlimit

Often a really hot guitar track has to
find a place in a crowded mix. This
is a good place to start.

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39 Rap Drums Hype

If you have a drum machine or mix
that calls for woof and hot treble,
send it through this curve.

40 Sizzle Cymbals

Reduce any live drum bleed-through
and emphasize the cymbals' place at
the high end of the mix.

Program Charts 5

41 Cardboard Tube

Remember when you were a kid and
you had a friend speak to you
through a cardboard tube?

42 Bathtub

Do you like the sound of singing in
the shower?

43 Presence

This curve gives the signal a little
more life when you want to get the
listener's attention.

44 Distance

Sometimes you want the signal to
not be so much of an attention
grabber.

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45 11kHz Sample Rate

If a very low sample rate like 11kHz
is used for effect, bandlimiting the
signal to half the sample rate
(around 5kHz) will help avoid some
nasty-sounding artifacts.

46 Next Door Neighbor

This is what it sounds like when
there's a party going on next door.

5 Program Charts

Note for programs 47-49

The following three programs are for DJs to “squash” the response of the music in order to
create a temporary effect or to make an announcement.

47 High DJ Isolation

See note for programs 47-49

48 Mid DJ Isolation

See note for programs 47-49

49 Low DJ Isolation

See note for programs 47-49

50 Nasal

This curve boosts the frequencies
that most sound engineers consider
to be hollow and honking.

Note for programs 51-59

These programs have been left blank so you will have places to store your programs right away.
They are different from program 00 “Flat” in that they have their Link function active. This is
what one of those programs looks like:

51-

59

Blank

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Store one of your programs here.

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6 Troubleshooting

Restoring the Factory Programs & Defaults

There is a power-up button combination that will restore the
DEQ224's User programs to the factory default programs. This
same combination of buttons will reset all of the Setup
functions to their default values. This procedure is called
"reinitializing."

To reinitialize the DEQ224, follow these steps:

1. Make sure you really want to erase every program you have

stored. That is what reinitializing the unit does.

2. If you haven't already done so, turn off the DEQ224.

3. Turn the unit on and press the [DOWN/UP] buttons during

the “splash screen.”

4. When you see the word "RESET" in large letters over the

[BAND SELECT] buttons, you may let go of the
[DOWN/UP] buttons. After a couple of seconds, the DEQ224

will return to Program mode.

Line Conditioners and Protectors

Although the DEQ224 is designed to tolerate typical voltage
variations, in today’s world the voltage coming from the AC line
may contain spikes or transients. These can cause audible noises,
and they can stress your gear and, over time, possibly cause a
failure. There are three main ways to protect against this, listed in
ascending order of cost and complexity:

• Line spike/surge protectors. Relatively inexpensive, these
are designed to protect against strong surges and spikes, acting
somewhat like fuses in that they need to be replaced if they’ve
been hit by an extremely strong spike.

• Line filters. These generally combine spike/surge protection
with filters that remove some line noise (dimmer hash,
transients from other appliances, etc.). A good example is the
Isobar™ series from Tripp Lite.

Care and Maintenance

Cleaning

Disconnect the AC power supply, then use a damp cloth to clean
the DEQ224’s metal and plastic surfaces. For heavy dirt, use a
non-abrasive household cleaner such as Formula 409™ or
Fantastik™. DO NOT SPRAY THE CLEANER DIRECTLY
ONTO THE FRONT OF THE UNIT AS IT MAY DESTROY
THE LUBRICANTS USED IN THE SWITCHES AND
CONTROLS! Spray onto a cloth, and then use the cloth to clean
the unit.

WARNING! Following the

rocedures in this section

will ERASE ALL OF
YOUR USER PROGRAMS
and replace them with the
User programs that shipped
with the DEQ224. Please be
certain this is what you want
to do before going through
these steps.

o not spray cleaning

olution of any sort onto the

ront panel of the DEQ224.

f a cleaning becomes

ecessary, spray a
ecommended cleaning
olution onto a cloth first,

nd use the cloth to clean

he front panel.

59

6 Troubleshooting

Troubleshooting Index

Symptoms Cause Solution

No audio at outputs. No input audio. Test with a known good

Bad cables. Replace the cables.
Destination is turned

Weak output signal. Input level weak. Increase level from source

Output level weak. Boost channel levels of

(Decide which is the case

Clip LED lights often. Input level too high. Reduce input level at

Output level too high. Reduce gain of problem

(Decide which is the case

Reduce Master Level in

Can’t edit program, can’t
select new program.

Numeric LED Display
keeps flashing “Lo.”

Must de-select all bands in
order to edit a single band.

DEQ224 won’t turn
on/won’t go into Setup
mode

DEQ224 won’t turn
on/won’t re-initialize

input.

down.

by pressing the Bypass
button.)

by pressing the Bypass
button.)

DEQ224 is locked. Unlock DEQ224 in Setup

DEQ224 is locked. Unlock DEQ224 in Setup

Release Edit Group

function set to Off.

Holding down buttons

when turning on power

Holding down buttons

when turning on power

Check the connections

and the level of the mixer
or amp to which the
DEQ224 is connected.

into DEQ224.

quiet program.

Boost Master Level in

Setup mode.

source.

bands within program.

Reduce channel levels of

that program.

Setup mode.

mode. Refer to page 41.

mode. Refer to page 41.

Set Release Edit Group

function to On in Setup
mode.

Turn on power first, then

hold down [STORE]
button to enter Setup
mode.

Turn on power first, then

press [DOWN/UP]
buttons to re-initialize.

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Troubleshooting 6

Refer All Servicing to Alesis

We believe that the DEQ224 is one of the best signal processors
that can be made using current technology, and should provide
years of trouble-free use. However, should problems occur, DO
NOT attempt to service the unit yourself unless you have training
and experience. Service on this product should be performed only
by qualified technicians. NO USER-SERVICEABLE PARTS
INSIDE.

Obtaining Repair Service

Before contacting Alesis, check over all your connections, and
make sure you’ve read the manual.

Customers in the USA and Canada:

If the problem persists, contact Alesis and request the Technical
Support department. Make sure you have the unit’s serial number
with you. Talk the problem over with one of our technicians; if
necessary, you will be given a return authorization (RA) number
and instructions on how to return the unit. All units must be
shipped prepaid and COD shipments will not be accepted.

For prompt service, indicate the RA number on the shipping label.
Units without an RA will not be accepted. If you do not have the
original packing, ship the unit in a sturdy carton, with shock­absorbing materials such as Styrofoam pellets (the kind without
CFCs, please) or "bubble-pack" surrounding the unit. Shipping
damage caused by inadequate packing is not covered by the Alesis
warranty.

Tape a note to the top of the unit describing the problem,
including your name and a phone number where Alesis can
contact you if necessary, as well as instructions on where you want
the product returned. Alesis will pay for standard one-way
shipping back to you on any repair covered under the terms of this
warranty. Next day service is available for a surcharge. Field repairs
are not authorized during the warranty period, and repair attempts
by unqualified personnel may invalidate the warranty.

Customers outside the USA and Canada:

Contact your local Alesis distributor for any warranty assistance.
The Alesis Limited Warranty applies only to products sold to users
in the USA and Canada. Customers outside of the USA and
Canada are not covered by this Limited Warranty and may or may
not be covered by an independent distributor warranty in the
country of sale. Do not return products to the factory unless you
have been given specific instructions to do so.

Internet Address:

Important information and advice is available on our web site:
http://www.alesis.com

Email may be addressed to [e-mail].

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6 Troubleshooting

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62

A

Specifications

Audio Input

Input Connectors: 2 Impedance-Balanced 1/4” TRS
jacks
Nominal Input Level: -10dBV (-15dBFS)
Maximum Input Level: +5dBV (1.78 Vrms)
Input Impedance: 10kΩ

Audio Output

Output Connectors: 2 Impedance-Balanced 1/4” TRS
jacks
Nominal Output Level: -10dBV (-15dBFS)
Maximum Output Level: +5dBV (1.78 Vrms)
Output Impedance: 220Ω

Audio Performance

Signal To Noise Ratio: >96 dB A-Weighted, Analog In
to Analog Out
THD+N: <0.007%, Analog In to Analog
Out
Frequency Response: 22-22kHz ± 0.50dB, Analog In
to Analog Out
Power Consumption: 15 Watts Max (90-230 VAC /
50-60 Hz)

Mechanical:

Size: 1.75" H x 8.5" W x 5.5" D
Rack Spaces: 1/2 Space
Weight: 2.0 lbs. (0.91 kg)

ll measurements done over
a 22 Hz - 22 kHz range with 1
kHz sine wave at -1dBFS
input. Impedances are
measured at 1 kHz.

63

Specifications

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Warranty / Contact

Alesis Limited Warranty

ALESIS CORPORATION ("ALESIS") warrants this product to be free of defects
in material and workmanship for a period of one (1) year for parts and for a period of
one (1) year for labor from the date of original retail purchase. This warranty is
enforceable only by the original retail purchaser and cannot be transferred or assigned.
For the most effective service, the purchaser should register the purchase on the
ALESIS website at http://www.alesis.com/support/warranty.htm.
During the warranty period ALESIS shall, at its sole and absolute option, either repair
or replace free of charge any product that proves to be defective on inspection by
ALESIS or its authorized service representative. In all cases disputes concerning this
warranty shall be resolved as prescribed by law.
To obtain warranty service, the purchaser must first call or write ALESIS at the
address and telephone number available on the Alesis Website to obtain a Return
Authorization Number and instructions concerning where to return the unit for
service. All inquiries must be accompanied by a description of the problem. All
authorized returns must be sent to ALESIS or an authorized ALESIS repair facility
postage prepaid, insured and properly packaged. Proof of purchase must be
presented in the form of a bill of sale, canceled check or some other positive proof
that the product is within the warranty period. ALESIS reserves the right to update
any unit returned for repair. ALESIS reserves the right to change or improve design
of the product at any time without prior notice.
This warranty does not cover claims for damage due to abuse, neglect, alteration or
attempted repair by unauthorized personnel, and is limited to failures arising during
normal use that are due to defects in material or workmanship in the product.
THE ABOVE WARRANTIES ARE IN LIEU OF ANY OTHER
WARRANTIES OR REPRESENTATIONS WHETHER EXPRESS OR
IMPLIED OR OTHERWISE, WITH RESPECT TO THE PRODUCT, AND
SPECIFICALLY EXCLUDE ANY IMPLIED WARRANTIES OF FITNESS
FOR A PARTICULAR PURPOSE OR MERCHANTABILITY OR OTHER
IMPLIED WARRANTIES. Some states do not allow limitations on how long an
implied warranty lasts, so the above limitation may not apply to you.
IN NO EVENT WILL ALESIS BE LIABLE FOR INCIDENTAL,
CONSEQUENTIAL, INDIRECT OR OTHER DAMAGES RESULTING
FROM THE BREACH OF ANY EXPRESS OR IMPLIED WARRANTY,
INCLUDING, AMONG OTHER THINGS, DAMAGE TO PROPERTY,
DAMAGE BASED ON INCONVENIENCE OR ON LOSS OF USE OF THE
PRODUCT, AND, TO THE EXTENT PERMITTED BY LAW, DAMAGES
FOR PERSONAL INJURY. Some states do not allow the exclusion or limitation of
incidental or consequential damages, so the above limitation or exclusion may not
apply to you.
THIS CONTRACT SHALL BE GOVERNED BY THE INTERNAL LAWS OF
THE STATE OF CALIFORNIA WITHOUT REFERENCE TO CONFLICTS
OF LAWS. This warranty gives you specific legal rights, and you may also have other
rights required by law which vary from state to state.
This warranty only applies to products sold to purchasers in the United States of
America or Canada. The terms of this warranty and any obligations of Alesis under
this warranty shall apply only within the country of sale. Without limiting the
foregoing, repairs under this warranty shall be made only by a duly authorized Alesis
service representative in the country of sale. For warranty information in all other
countries please refer to your local distributor.

or more effective

ervice and product

update notices, please

egister your DEQ224

nline at:

ttp://www.alesis.com

upport/warranty.htm

65

Warranty/Contact

Alesis Contact Information

Alesis Distribution, LLC
Los Angeles, CA USA

E-mail: [e-mail]
Website: http://www.alesis.com

Alesis DEQ224 Reference Manual
Revision A by Randy Lee and Brooks Bruner

Copyright 2003, Alesis Distribution, LLC. All rights reserved
Reproduction in whole or in part is prohibited. “DEQ224” is a
trademark of Alesis Distribution, LLC. Specifications subject to
change without notice.

7-51-0136-A
02/21/2003

66