Behringer MDX1400 User Manual

Users Manual

ENGLISH

PRO MDX1400

Version 1.4 June 2001

AUTOCOM

www.behringer.com

AUTOCOM PRO MDX1400

SAFETY INSTRUCTIONS

CAUTION: To reduce the risk of electric shock, do not remove

the cover (or back). No user serviceable parts inside; refer servicing to qualified personnel.

WARNING: To reduce the risk of fire or electric shock, do not

expose this appliance to rain or moisture.

This symbol, wherever it appears, alerts you to the presence of uninsulated dangerous voltage inside the enclosurevoltage that may be sufficient to constitute a risk of shock.

DETAILED SAFETY INSTRUCTIONS:

All the safety and operation instructions should be read before the appliance is operated.

Retain Instructions:

The safety and operating instructions should be retained for future reference.

Heed Warnings:

All warnings on the appliance and in the operating instructions should be adhered to.

Follow instructions:

All operation and user instructions should be followed.

Water and Moisture:

The appliance should not be used near water (e.g. near a bathtub, washbowl, kitchen sink, laundry tub, in a wet basement, or near a swimming pool etc.).

Ventilation:

The appliance should be situated so that its location or position does not interfere with its proper ventilation. For example, the appliance should not be situated on a bed, sofa, rug, or similar surface that may block the ventilation openings, or placed in a built-in installation, such as a bookcase or cabinet that may impede the flow of air through the ventilation openings.

Heat:

The appliance should be situated away from heat sources such as radiators, heat registers, stoves, or other appliances (including amplifiers) that produce heat.

Power Source:

The appliance should be connected to a power supply only of the type described in the operating instructions or as marked on the appliance.

Grounding or Polarization:

Precautions should be taken so that the grounding or polarization means of an appliance is not defeated.

Power-Cord Protection:

Power supply cords should be routed so that they are not likely to be walked on or pinched by items placed upon or against them, paying particular attention to cords and plugs, convenience receptacles and the point where they exit from the appliance.

Cleaning:

The appliance should be cleaned only as recommended by the manufacturer.

Non-use Periods:

The power cord of the appliance should be unplugged from the outlet when left unused for a long period of time.

Debris and Liquid Entry:

Care should be taken that debris and/or liquids do not enter the enclosure through openings.

Damage Requiring Service:

The appliance should be serviced by qualified service personnel when:

- The power supply cord or the plug has been damaged; or

- Debris or liquid has entered the appliance; or

- The appliance has been exposed to rain; or

- The appliance does not appear to operate normally or exhibits a marked change in performance; or

- The appliance has been dropped, or the enclosure damaged.

Servicing:

The user should not attempt to service the appliance beyond that which is described in the operating instructions. All other servicing should be referred to qualified service personnel.

This symbol, wherever it appears, alerts you to important operating and maintenance instructions in the accompanying literature. Read the manual.

AUTOCOM PRO MDX1400

FOREWORD

Dear Customer,

Welcome to the team of AUTOCOM PRO users and thank you very much for expressing your confidence in Behringer products by purchasing this unit.

It is one of my most pleasant tasks to write this letter to you, because it is the culmination of many months of hard work delivered by our engineering team to reach a very ambitious goal: making an outstanding device better still. The AUTOCOM has for quite a long time been a standard tool used by numerous studios and PA rental companies. The task to improve one of our best-selling products certainly meant a great deal of responsibility, which we assumed by focusing on you, the discerning user and musician. It also meant a lot of work and night shifts to accomplish this goal. But it was fun, too. Developing a product usually brings a lot of people together, and what a great feeling it is when everybody who participated in such a project can be proud of what weve achieved.

It is our philosophy to share our joy with you, because you are the most important member of the BEHRINGER family. With your highly competent suggestions for new products youve greatly contributed to shaping our company and making it successful. In return, we guarantee you uncompromising quality (manufactured under ISO9000 certified management system) as well as excellent technical and audio properties at an extremely favorable price. All of this will enable you to fully unfold your creativity without being hampered by budget constraints.

We are often asked how we can make it to produce such high-grade devices at such unbelievably low prices. The answer is quite simple: its you, our customers! Many satisfied customers means large sales volumes enabling us to get better conditions of purchase for components, etc. Isnt it only fair to pass this benefit back to you? Because we know that your success is our success, too!

I would like to thank all people whose help on Project AUTOCOM PRO has made it all possible. Everybody has made very personal contributions, starting from the designers of the unit via the many staff members our our company to you, the user of BEHRINGER products.

My friends, its been worth the trouble!

Thank you very much,

Uli Behringer

AUTOCOM PRO MDX1400

AUTOCOM

Interactive 2-channel expander/gate/compressor/enhancer of the reference class

PRO

IKA (Interactive Knee Adaptation) compressor concept combines the advantages of hard knee and soft knee characteristics

Attack and Release times controllable automatically or manually

Switchable highpass filter in control signal path avoids low-frequency signals from dominating compressor action

Compression characteristics switchable between IKA and hard knee characteristics

IRC circuit in expander/gate allows for inaudible elimination of disturbing noise signals

Dynamic Enhancer for compression dependent equalization

Extremely low-noise operational amplifiers and high-grade VCAs

MDX1400

High-quality detented potentiometers and backlit switches

Stereo Couple function selectable with real totaling of RMS output

Accurate 12-digit LED meters for input level, output level and gain reduction

Switchable sidechain input with sidechain monitor function

Operating level switchable from +4 dBu to -10 dBV

Servo-balanced gold-plated XLR and 1/4" TRS connectors

High-grade output transformer BEHRINGER OT-1 can be retrofitted

Manufactured under ISO9000 certified management system

AUTOCOM PRO MDX1400

TABLE OF CONTENT

1. INTRODUCTION..................................................................................................................... 6

1.1 The Design Concept ........................................................................................................................ 6

1.2 Before you begin ............................................................................................................................. 7

2. CONTROLS ............................................................................................................................8

2.1 Expander/Gate Section ................................................................................................................... 8

2.2 Compressor Section ....................................................................................................................... 9

2.3 Dynamic Enhancer Section ........................................................................................................... 10

2.4 Rear Panel Control Elements Of The AUTOCOM PRO .................................................................. 10

3. APPLICATIONS ..................................................................................................................... 11

3.1 Compression/Levelling/Limiting/Clipping ......................................................................................... 11

3.2 Expander/Gate Section ................................................................................................................. 12

3.2.1 Controlling Leakage In The Studio ....................................................................................... 12

3.2.2 Initial Settings For The Expander/Gate Section ................................................................... 13

3.2.3 Reducing Leakage In Stage Mics ........................................................................................ 13

3.2.4 Reducing Feedback In Stage Mics ...................................................................................... 14

3.2.5 Noise Reduction On Effects Paths ...................................................................................... 14

3.2.6 Creative Use Of The Expander/Gate Section ....................................................................... 14

3.3 Compressor Section ..................................................................................................................... 14

3.3.1 Initial Settings For The Compressor Section ....................................................................... 15

3.3.2 The AUTOCOM PRO As A Sound Effects Unit .................................................................... 16

3.3.3 The Muffling Effect Of A Compressor ................................................................................. 16

3.4 Dynamic Enhancer Section ........................................................................................................... 16

3.4.1 Initial Settings For The Dynamic Enhancer Section ............................................................. 17

4. SPECIAL APPLICATIONS ..................................................................................................... 17

4.1 Using The AUTOCOM PRO For Recording And Cassette Duplication ............................................ 17

4.1.1 The AUTOCOM PRO In Digital Recording And Sampling ..................................................... 18

4.1.2 The AUTOCOM PRO In Mastering ...................................................................................... 18

4.2 The AUTOCOM PRO As A Protective Device ................................................................................. 18

4.2.1 Protection Of A System With A Passive Crossover .............................................................. 18

4.2.2 Protection Of A System With An Active Crossover ............................................................... 19

4.2.3 Improving The Sound Of A Processor System ..................................................................... 19

4.3 The AUTOCOM PRO In Broadcast ................................................................................................ 19

5. EXTERNAL SIDECHAIN APPLICATIONS............................................................................ 20

5.1 The Sidechain Function ................................................................................................................. 20

5.2 Using An Equalizer In The Sidechain Path .................................................................................... 20

5.2.1 The AUTOCOM PRO As A De-Esser ................................................................................. 20

5.2.2 Frequency Selective Filtering Of Unwanted Signals ............................................................. 21

5.2.3 Suppressing Instruments During Recording ......................................................................... 21

5.2.4 Emphasizing Musical Instruments During Recording ........................................................... 21

5.3 Anticipated Compression .............................................................................................................. 22

5.4 Voice-Over Compression (Ducking) ........................................................................................... 22

5.5 Triggering Additional Sounds From A Rhythm Track ...................................................................... 22

6. TECHNICAL BACKGROUND .............................................................................................. 22

6.1 Noise As A Physical Phenomenon ................................................................................................ 22

6.2 What Are Audio Dynamics? .......................................................................................................... 22

6.3 Compressors/Limiters .........................................................................................................24

6.4 Expanders/Noise Gates ...................................................................................................... 24

7. AUDIO CONNECTIONS ....................................................................................................... 25

7.1 Inputs And Outputs ....................................................................................................................... 25

7.1.1 Balanced Inputs And Outputs .............................................................................................. 25

7.1.2 Transformer Balanced Outputs (Optional) ............................................................................ 25

8. TECHNICAL DATA ................................................................................................................ 27

9. WARRANTY ........................................................................................................................... 29

AUTOCOM PRO MDX1400

1. INTRODUCTION

In purchasing the new AUTOCOM PRO Model MDX1400, you have acquired an extremely efficient and universal dynamics processor, which combines the most commonly used dynamic functions within a compact stereo unit: every channel has its own independent Compressor/Limiter, an Expander/Gate and a Dynamic Enhancer. The precision and flexibility of the functions are the main outstanding features of this high end unit.

Advanced BEHRINGER Technology

Compared to its predecessors, the AUTOCOM PRO offers several advanced features such as the extended LED meters, balanced inputs and outputs, a couple function for the two channels and the sidechain filter. Additionally, we have succeeded in refining the audio properties as well as the circuit topology.

For the first time, the AUTOCOM PRO MDX1400 uses SMD technology (Surface Mounted Device). These sub-miniature components known from aerospace technology allow for an extreme packing density, plus improve the units reliability. Additionally, the unit is manufactured under ISO9000 certified management system.

1.1 The Design Concept

The philosophy behind BEHRINGER products guarantees a no-compromise circuit design and employs the best choice of components. The operational amplifiers NJM4580 which are used in the AUTOCOM PRO, are exceptional. They boast extreme linearity and very low distortion characteristics. The most important aspect of the AUTOCOM PRO design is a radical VCA implementation which results in outstanding technical specification and excellent performance. To complement this design the choice of components includes high precision resistors and capacitors, detent potentiometers and several other stringently selected elements.

Despite the extremely complex internal circuitry, the unit has a control surface which is clearly laid out and easy to understand. The internal design of the unit, together with its external sidechain path, gives the user all the creative flexibility when processing sound.

IKA (Interactive Knee Adaptation) Compressor

Our proven IKA (Interactive Knee Adaptation) circuit successfully combines the concept of a hard knee compressor with the characteristics of a soft knee approach. This program-dependent regulation scheme forms the prerequisite both for inaudible and musical program compression and for creative and highly effective dynamics processing.

The chosen value for the compression-ratio is being reached after the signals level is higher then 10 dB above the treshold point. This stands for an extremely smooth impact of the compression. Thereby a convincingly dense audiomaterial can be achieved: Even at extreme levels of compression or while processing critical audiodata (e. g. classical music), your material stays musical, transparent and free from breathing or pumplike effects in a wide range. With its IKA circuit the AUTOCOM PRO is capable of delivering outstanding musical results both in studio and live PA applications.

Additionally, the AUTOCOM PROs sidechain filter allows for limiting the influence low-frequency signal portions usually have on the control logic, so that the compression ratio is mainly determined by those frequencies that are essential to the loudness perceived by the listener  the midrange frequencies.

IRC (Interactive Ratio Control) Expander

A basic problem in the use of a compressor is the fact that the noise floor is highly amplified during quiet sections or when there are music pauses. This effect is exaggerated when the compression ratio is inappropriate. In order to eliminate this problem, one would normally use an additional expander or gate. The noise is then simply faded out in the quiet sections. However, simple expanders, even when they are used correctly, drastically cut signals below the preset threshold. This effect becomes more noticeable during the transition from signal to noise floor. This can mean, that the start or end of words can be cut on a vocal track.

A newly developed IRC (Interactive Ratio Control) Expander has been integrated into the AUTOCOM PRO the ratio of which, is automatically adjusted, depending on the program material. The result is an expander which is less critical of adjustment and which is more tolerant in the presence of those signals which appear slightly above the noise floor. Because of its new IRC circuit design, the BEHRINGER AUTOCOM PROs Expander/

1. INTRODUCTION

AUTOCOM PRO MDX1400

Gate section can be used as an independent unit to eradicate noise offering almost limitless possibilities within this application.

The BEHRINGER Dynamic Enhancer

One of the most common negative effects of broadband compressors is the dulled or squashed sound that is produced when it is applied to composite music, since high-energy low frequency instruments cause a compressor to reduce the overall gain. Any high frequency instrument which occurs at the same time will also be reduced in level. This spectral intermodulation causes the squashed sound effect.

The solution to this problem is the new AUTOCOM PROs Dynamic Enhancer which allows for selective replacement of high-end loss accrued through use of compression. Since the Enhancer tracks the amount of compression, enhancement will not be added when no compression throughout the mix without any additional outboard enhancer etc.

+ The following instructions should familiarize you with the special terms used first, so that you

can get to know all the functions of the unit. After you have read the instructions carefully, please put them away safely, so that you can refer to them again if necessary.

1.2 Before you begin

Your BEHRINGER AUTOCOM PRO was carefully packed in the factory and the packaging is designed to protect the unit from rough handling. Nevertheless, we recommend that you carefully examine the packaging and its contents for any signs of physical damage, which may have occurred during transit.

+ If the unit is damaged, please do not return it to BEHRINGER, but notify your dealer and the

shipping company immediately, otherwise claims for damage or replacement may not be granted. Shipping claims must be made by the consignee.

The BEHRINGER AUTOCOM PRO fits into one standard 19" rack unit of space. Please allow at least an additional 4" depth for the connectors on the back panel.

Be sure that there is enough space around the unit for cooling and please do not place the ULTRA-GRAPHPRO on high temperature devices such as power amplifiers etc. to avoid overheating.

+ Before you connect your AUTOCOM PRO to the mains, please make sure that your local volt-

age matches the voltage required by the unit!

The fuse holder on the female mains connector has 3 triangular markers, with two of these triangles opposing each other. Your AUTOCOM PRO is set to the operating voltage printed next to these markers, and can be set to another voltage by turning the fuse holder by 180°. CAUTION: this instruction does not apply to export

models exclusively designed, e.g., for 115 V operation!

The mains connection of the AUTOCOM PRO is made by using the enclosed mains cable and a standard IEC receptacle. It meets all of the international safety certification requirements.

+ Please make sure that all units have a proper ground connection. For your own safety, never

remove or disable the ground conductor of the unit or of the AC power cable.

1. INTRODUCTION

AUTOCOM PRO MDX1400

2. CONTROLS

Fig. 2.1: AUTOCOM PRO front panel

The BEHRINGER AUTOCOM PRO has two identical channels. Each channel is equipped with 8 backlit push-buttons, 7 rotary controls and 26 LEDs. The COUPLE switch is for stereo operation:

By engaging the COUPLE switch the AUTOCOM PRO is converted to stereo mode, where the controls of the left channel take over the control of both audio channels. The control signal for the control characteristic consists of either the sum of the left and right audio signal or the sum of the external audio signals, which are being fed into both SC RETURN connectors. By pressing the COUPLE switch, you override all the controls and switches of channel 2 with the exception of the IN/OUT, SC EXT, SC MON, SC FILTER and I/O METER switches as well as the OUTPUT and PROCESS controls. As a result, the controls of channel 1 take over the functions of channel 2.

+ Should you wish to use the SC EXT function in stereo mode, then be sure that both SC RETURN

jacks are connected to the external control signal, and that the SC EXT switches on both channels are engaged.

2.1 Expander/Gate Section

Fig. 2.2: Control elements of expander/gate section

Use the THRESHOLD control to determine the threshold point below which expansion occurs. The range of this control is from OFF to +10 dB.

When a signal above the threshold value is applied, the - LED lights up, while the + LED lights up when expansion occurs.

To optimally adapt the expander/gate to the program material, the RELEASE switch allows for selecting a SLOW or FAST release time. When you engage this switch, the expander responds with a slow release. As a general rule, percussive material with little or no ambience is processed using the FAST release mode, whereas signals with long decay or with heavy ambience require the SLOW release mode.

2. CONTROLS

2.2 Compressor Section

AUTOCOM PRO MDX1400

The THRESHOLD control sets the threshold point for the compressor section. It has a range of -40 to +20 dB. If the channel is switched to INTERACTIVE mode (Interactive Knee Adaptation), a Soft Knee characteristic is applied to the signal exceeding the threshold point by a maximum of 10 dB. Above 10 dB, the signal would experience Hard Knee compression.

The RATIO control determines the ratio between the input and output level for all signals exceeding the threshold point. If the INTERACTIVE mode is used, this control determines the ratio between input and output levels for signals exceeding the threshold point by more than 10 dB. The control range can be adjusted from 1:1 to oo:1.

The ATTACK control determines the rate by which the compressor responds to the signal which exceeds the threshold. This control can be adjusted from 0.1 to 200 milliseconds.

The RELEASE control determines the rate that the compressor returns to unity gain after falling below the threshold level. This control can be adjusted from 0.05 to 4 seconds.

By activating the AUTO switch, the ATTACK and RELEASE controls are disabled and the attack and release rates are automatically derived from the program material. This function allows for unobtrusive musical compression of signals or mixes with widely varying dynamics. Only if set to MANUAL the settings of the attack and release controls will function.

The OUTPUT control allows for the increase or decrease of the output signal by a maximum of 20 dB. Thus, a level loss due to the compression or limiting process can be compensated for.

When activated, the SC EXT switch severs the connection between the audio input and the sidechain path, whilst at the same time allowing an external signal to be sourced at the SC RETURN jack on the rear panel.

Using the SC MON switch will enable you to connect the sidechain control signal to the audio output, whilst at the same time muting the audio input. This function provides you with the ability to monitor the sidechain signal that is returned via inserted equalizers or other external processors. The SC MONITOR function will assist you with tuning equalizer parameters for example.

14 16

Fig. 2.3: Control elements of the compressor section

13108976155

+ Please note when the SC MON switch is engaged, the audio processing facility of the respec-

tive channel is disabled. When this function is active, a visual indication will be provided by the switches LED, which will blink.

The IN/OUT switch activates the corresponding channel. This switch acts as a so-called hard-bypass, which means that when the switch is OUT, the input jack is directly linked to the output jack. Normally, this switch is used to perform a direct A/B comparison between the unprocessed and the compressed or limited signals.

Press the INTERACTIVE switch to change from hard knee to IKA characteristics. IKA provides a very subtle and musical compression of the program material and should therefore be used whenever compression is expected to be more or less inaudible.

2. CONTROLS

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