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) ..............
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..
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.
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.
Introduction 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.
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Important Safety Instructions Important Safety Instructions (English) Safety symbols used in this product This symbol alerts the user that there are important operating and maintenance instructions in the literature accompanying this unit. This symbol warns the user of uninsulated voltage within the unit that can cause dangerous electric shocks. This symbol warns the user that output connectors contain voltages that can cause dangerous electrical shock.
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.
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.
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.
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.
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.
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.
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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.
1 Quick Start Guide 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.
Quick Start Guide 1 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. 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.
1 18 Quick Start Guide
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.
2 Connections 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.
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). This cable splits the TRS insert jack into two unbalanced mono connectors.
2 Connections 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.
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.
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.
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.
3 Basics of Equalization 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.
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.
3 Basics of Equalization 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.
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 3059. 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.
3 Basics of Equalization 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.
Basics of Equalization 3 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.
3 Basics of Equalization 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.
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.
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).
Basics of Equalization 3 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.
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.
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.
3 Basics of Equalization 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.
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.
3 Basics of Equalization 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.
Basics of Equalization 3 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.
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.
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.
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.
Basics of Equalization 3 In the next illustration, the difference between a narrow Q and a wide Q is seen: Variable 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.
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.
Basics of Equalization 3 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.
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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.
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.
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 Front panel The DEQ224 will not affect the signal; the output signal will sound the same as the input signal.
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.
Program Charts 11b 5 Female Vocal Lows reduced to avoid rumble, highend emphasized for intelligibility. 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.
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).
Program Charts 26 5 Narrow Cut 5 (8.2kHz) See note for programs 16-20 and 22-26 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.
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.
Program Charts 40 5 Sizzle Cymbals Reduce any live drum bleed-through and emphasize the cymbals' place at the high end of the mix. 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.
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.
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.
6 Troubleshooting Troubleshooting Index Symptoms No audio at outputs. Cause No input audio. Bad cables. Destination is turned down. Weak output signal. Input level weak. Output level weak. Clip LED lights often. (Decide which is the case by pressing the Bypass button.) Input level too high. Output level too high. (Decide which is the case by pressing the Bypass button.) 60 Can’t edit program, can’t select new program. Numeric LED Display keeps flashing “Lo.
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.
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Specifications Audio Input Input Connectors: Nominal Input Level: Maximum Input Level: Input Impedance: 2 Impedance-Balanced 1/4” TRS jacks -10dBV (-15dBFS) +5dBV (1.78 Vrms) 10kΩ All measurements done over a 22 Hz - 22 kHz range with 1 kHz sine wave at -1dBFS input. Impedances are measured at 1 kHz. Audio Output Output Connectors: Nominal Output Level: Maximum Output Level: Output Impedance: 2 Impedance-Balanced 1/4” TRS jacks -10dBV (-15dBFS) +5dBV (1.
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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.
Warranty/Contact Alesis Contact Information Alesis Distribution, LLC Los Angeles, CA USA E-mail: Website: support@alesis.com 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.
