dbx 2-Series Graphic Equalizers

Introduction

Congratulations on your purchase of a dbx 2-Series Graphic Equalizer. These equalizers offer a wide range of professional features, including:

• Silent In/Out Switching
• Signal Present and Clip LEDs
• Precision Wein Bridge Filters
• 20mm Faders
• Constant "Q" Design
• Switchable Low Cut Filter
• Selectable 12dB or 6dB Range
• Balanced XLR, 1/4" Inputs
• Servo-Balanced XLR, 1/4" Outputs

dbx is confident that you will be pleased with the high performance, superb sound quality, and reliability that its equalizers are known for.

Important Safety Instructions

⚠️ CAUTION: RISK OF ELECTRIC SHOCK ⚡ DO NOT OPEN ?

The lightning flash with arrowhead symbol (⚡), within an equilateral triangle, is intended to alert the user to the presence of uninsulated "dangerous voltage" within the product's enclosure that may be of sufficient magnitude to constitute a risk of electric shock to persons. The exclamation point within an equilateral triangle (❗) is intended to alert the user to the presence of important operating and maintenance instructions in the literature accompanying the device.

Please read the entire owner's manual before connecting to a sound system to minimize the risk of injury, damage, or hearing loss.

English Instructions:

1. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
4. Follow all instructions.
5. To reduce the risk of fire or electric shock, do not expose this apparatus to rain or moisture.
6. Do not use this apparatus near water.
7. Clean only with dry cloth.
8. Do not block any ventilation openings. Install in accordance with the manufacturer's instructions.
9. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.
10. Do not defeat the safety purpose of the polarized or 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. If the provided plug does not fit into your outlet, consult an electrician for replacement of the obsolete outlet.
11. Protect the power cord from being walked on or pinched, particularly at plugs, convenience receptacles, and the point where they exit from the apparatus.
12. Only use attachments/accessories specified by the manufacturer.
13. Use only with the cart, stand, tripod, rack, or table specified by the manufacturer, or sold with the apparatus. When a cart is used, use caution when moving the cart/apparatus combination to avoid injury from tip-over.
14. Unplug this apparatus during lightning storms or when unused for long periods of time.
15. Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been damaged in any way, such as 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.

French Instructions (Consignes de sécurité à lire attentivement):

1. Lisez ces instructions.
2. Conservez ces instructions.
3. Observez les avertissements.
4. Suivez ces instructions.
5. Pour réduire le risque de feu ou la décharge électrique, ne pas exposer cet appareil pour pleuvoir ou l'humidité.
6. Ne pas utiliser l'appareil près de l'eau.
7. Le nettoyer à l'aide d'un tissus sec.
8. Ne pas bloquer les ouvertures de ventilation, installer selon les consignes du fabricant.
9. Eloigner des sources de chaleur tel: radiateurs, fourneaux ou autres appareils qui produisent de la chaleur.
10. Ne pas modifier ou amputer le système de la mise à terre. Une prise avec mise à terre comprend deux lames dont une plus large ainsi qu'une mise à terre: ne pas la couper ou la modifier. Si la prise murale n'accepte pas la fiche, consulter un électricien pour qu'il remplace la prise désuète.
11. Protéger le cordon de secteur contre tous bris ou pincement qui pourraient l'endommager, soit à la fiche murale ou à l'appareil.
12. N'employer que les accessoires recommandés par le fabricant.
13. N'utiliser qu'avec les systèmes de fixation, chariots, trépied ou autres, approuvés par le fabricant ou vendus avec l'appareil.
14. Débrancher l'appareil lors des orages électriques ou si inutilisé pendant une longue période de temps.
15. Un entretient effectué par un centre de service accrédité est exigé si l'appareil a été endommagé de quelque façon: si il a été exposé à la pluie, l'humidité ou s'il ne fonctionne pas normalement ou qu'il a été échappé.

FCC Compliance

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.
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 both commercial and residential installations. This equipment generates, uses, and can radiate radiofrequency 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.

Equalizer Technology

dbx 2-Series Equalizers use "Q" enhanced Wein bridge filters and interleaved summing for constant "Q", low ripple, and minimum filter interaction. A servo-balanced output stage simulates a true transformer output to allow interfacing with virtually any type of load.

Connectors & Cables

Your dbx equalizer is provided with two different connector types for interfacing with professional audio products:

• 1/4 inch stereo phone jacks (TRS)
• Three pin XLR type connectors

Inputs and servo-balanced outputs can be used balanced or unbalanced. Balanced connections are recommended between all components in your system to eliminate ground-loop induced hum and noise.

Connection Diagrams

Balanced TRS Phone Jack: Diagram showing a TRS phone jack with Tip (+), Ring (-), and Sleeve (Ground) connections.

Unbalanced TS Phone Jack: Diagram showing a TS phone jack with Tip (+) and Sleeve (Ground) connections.

XLR Connectors: Diagrams showing XLR connectors with Pin 1 (Ground), Pin 2 (Positive/+), and Pin 3 (Negative/-) connections for both male and female types. For unbalanced input on XLR, the signal should be on the + connection (Pin 2) and the - connection (Pin 3) tied to ground (Pin 1).

Unbalanced Connections and Grounding

If unbalanced connectors must be used, the negative lead of the connector should be tied to the ground lead. Using unbalanced connections could result in chassis ground-loop noise. Altering the signal/chassis ground relationship in equipment connected to your unit may eliminate the noise.

Physical Description

Front Panel

The front panel features two channels, each labeled 'CHANNEL 1' and 'CHANNEL 2'. Each channel has a 'SIGNAL' LED and a 'CLIP' LED. A row of 15 sliders per channel controls the frequency response. A 'GAIN' control knob is present for each channel, with a range from -10 to +10 dB, center-detented at unity gain (0 dB). The unit is labeled 'Graphic Equalizer' with the 'dbx by HARMAN' logo.

The front panel also includes controls for 'RANGE EG' (selectable 12dB or 6dB) and a 'HIGH-PASS FILTER' frequency selection control.

Rear Panel

The rear panel includes 'CHANNEL 1' and 'CHANNEL 2' sections. Each section has 'INPUT' and 'OUTPUT' connectors. These include female XLR and 6.35mm TRS jacks for balanced and unbalanced signals. The output circuits are active and servo-balanced, maintaining a constant output level regardless of grounding. A 'WOOFER' output section with 'FREQ' and 'LEVEL' controls is also present. A 'POWER' switch of the rocker type applies power to the unit, and an IEC receptacle is provided for AC mains connection (220-240V, 50/60Hz).

Installation and AC Power

Installation

Use four screws and washers when rack mounting the Equalizer. For mobile use, the unit should be further secured.

AC Power

Your equalizer should be connected to a standard 3-wire grounded electrical outlet supplying 220-240 Volts, 50-60 Hz. To reduce the risk of ground loop hum, connect all audio equipment to the same electrical power source. Do not remove the AC plug ground pin, as a potential shock hazard could result.

This unit will perform normally within the AC voltage range specified above. Voltages less than this, as found in "brown-out" conditions, may reduce performance. No user serviceable parts are inside the chassis. Refer all servicing to qualified service personnel. Overall power consumption is less than 15 watts.

NOTE: The power switch does NOT isolate the appliance from mains. Make sure the mains power socket or an alternative disconnect device is near by and easily accessible. When the product is connected to mains, the line-filter and the input of the fuse are energized.

Typical Applications

General Tone Control

The graphic equalizer is a very useful device for general tone shaping because it is intuitive and easy to adjust. The visual reference provided by the slider position gives an approximate idea of the frequency response generated, with lower frequencies on the left and higher frequencies on the right. To use the power of an equalizer effectively, translate your desired tone into a range of numerical frequencies. This is simple after a little practice. Here are a few references for starting points:

• Very low bass (e.g., "wind" in a kick drum, felt as much as heard): 40Hz-80Hz.
• Low register of a male voice: 200Hz.
• Low register of a female voice: 350Hz.
• Lower midrange ("warmth" frequencies): 400Hz-1KHz.
• Upper midrange ("harshness", snare drum "bite", "hot" sound): 2.5KHz-4KHz.
• Sibilance ("sss" sounds, cymbal "sizzle"): 8KHz-15KHz.

Use these starting points as a guide when you want more or less of these sounds. Adjust by ear from there. It is always a good idea to remember that a little equalization usually works out much better than a lot, and that there are many audio problems which cannot be solved with equalization alone.

Feedback Control

A graphic equalizer can provide some control over moderate feedback problems, but lacks the flexibility for severe situations. Achieve best results by eliminating one or two feedback points with sliders set for no more than a 6dB cut. You can find feedback points by boosting sliders in succession to determine which frequency ranges contain feedback modes, and then cutting those ranges. Be very careful to avoid explosive feedback and possible system and hearing damage. If you find feedback points with many equalizer bands, cutting every band may not help (it will only reduce system gain). The combination of a graphic equalizer for tone control and a parametric equalizer for feedback control is highly recommended.

Console Channel Equalization

Many mixing consoles provide only simple equalization for individual channels. If your console has channel inserts, you can patch your graphic equalizer into a channel requiring more precise equalization.

Large Room Equalization

Large rooms tend to suffer from multiple reflections with long time delays, long reverberation times, and "ring modes", all leading to reduced intelligibility and a generally "muddy" sound. As sound travels long distances, high frequencies are attenuated more than low frequencies. In general, large rooms benefit from some low frequency roll-off, high frequency boost, and attenuation of ring mode frequencies. As with feedback control, a graphic equalizer can help reduce an isolated ring-mode or two, but a tunable narrow-band equalizer such as a parametric is more effective.

Specifications