Behringer XR4400 Owner's Manual

User Manual

MULTIGATE PRO XR4400

Reference-Class 4-Channel Expander/Gate

2 MULTIGATE PRO XR4400 User Manual

Table of Contents

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

Legal Disclaimer ............................................................. 3

Limited warranty ............................................................ 3

1. Introduction ............................................................... 4

1.1 Technical background ....................................................... 4

2. The Design Concept ..................................................6

2.1 High quality components and design......................... 6

2.2 Inputs and outputs ............................................................ 6

3. Installation ................................................................. 6

3.1 Rack mounting ..................................................................... 6

3.2 Mains voltage ....................................................................... 6

3.3 Audio connections ............................................................. 6

4. Controls ...................................................................... 7

4.1 The front panel control elements ................................. 7

4.2 The rear panel elements .................................................. 8

5. Technical Background ............................................... 8

5.1 EXPANDER mode ................................................................ 8

5.2 Interactive control functions .......................................... 8

5.3 FLEXLINK function ............................................................ 10

5.4 The SIDECHAIN lter ........................................................ 10

6. Applications ............................................................. 10

6.1 Basic setting ........................................................................ 10

6.2 Proper positioning of microphones .......................... 11

6.3 Applications ...................................................................... 12

7. Specications ........................................................... 12

3 MULTIGATE PRO XR4400 User Manual

9. Do not defeat the safety purpose of the polarized

TO BIND MUSICGROUP BY ANY EXPRESS OR IMPLIED

Important Safety Instructions

Terminals marked with this symbol carry electrical current of su cient magnitude

to constitute risk of electric shock. Use only high-quality professional speaker cables with ¼" TS or twist-locking plugs pre-installed. Allother installation or modi cation should be performed only by quali edpersonnel.

This symbol, wherever it appears,

alertsyou to the presence of uninsulated

dangerous voltage inside the enclosure-voltage that may be su cient to constitute a risk ofshock.

This symbol, wherever it appears,

alertsyou to important operating and

maintenance instructions in the accompanying literature. Please read the manual.

Caution

To reduce the risk of electric shock, donot

remove the top cover (or the rear section). No user serviceable parts inside. Refer servicing to quali ed personnel.

Caution

To reduce the risk of  re or electric shock,

do not expose this appliance to rain and moisture. The apparatus shall not be exposed to dripping or splashing liquids and no objects  lled with liquids, suchas vases, shall be placed on the apparatus.

Caution

These service instructions are for use

by quali ed service personnel only. Toreduce the risk of electric shock do not perform any servicing other than that contained in the operation instructions. Repairs have to be performed by quali ed servicepersonnel.

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  t into your outlet, consult an electrician for replacement of the obsolete outlet.

10. Protect the power cord from being walked on or pinched particularly at plugs, convenience receptacles, and the point where they exit from the apparatus.

11. Use only attachments/accessories speci ed by themanufacturer.

12. Use only with the cart, stand, tripod, bracket, or table speci ed 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.

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

14. Refer all servicing to quali ed 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.

15. The apparatus shall be connected to a MAINS socket outlet with a protective earthing connection.

16. Where the MAINS plug or an appliance coupler is used as the disconnect device, the disconnect device shall remain readily operable.

UNDERTAKING OR REPRESENTATION. THIS MANUAL IS COPYRIGHTED. NO PART OF THIS MANUAL MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM OR BY ANY MEANS, ELECTRONIC OR MECHANICAL, INCLUDING PHOTOCOPYING AND RECORDING OF ANY KIND, FOR ANY PURPOSE, WITHOUT THE EXPRESS WRITTEN PERMISSION OF MUSICGROUPIPLTD.

LIMITED WARRANTY

For the applicable warranty terms and conditions and additional information regarding MUSIC Group’s Limited Warranty, please see complete details online at www.music-group.com/warranty.

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 dry cloth.

7. Do not block any ventilation openings. Install in

accordance with the manufacturer’s instruc tions.

8. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including ampli ers) that produce heat.

LEGAL DISCLAIMER

TECHNICAL SPECIFICATIONS AND APPEARANCES ARE SUBJECT TO CHANGE WITHOUT NOTICE AND ACCURACY IS NOT GUARANTEED. BEHRINGER, KLARKTEKNIK, MIDAS, BUGERA, AND TURBOSOUND ARE PART OF THE MUSIC GROUP MUSICGROUP.COM. ALL TRADEMARKS ARE THE PROPERTY OF THEIR RESPECTIVE OWNERS. MUSICGROUP ACCEPTS NO LIABILITY FOR ANY LOSS WHICH MAY BE SUFFERED BY ANY PERSON WHO RELIES EITHER WHOLLY OR IN PART UPON ANY DESCRIPTION, PHOTOGRAPH OR STATEMENT CONTAINED HEREIN. COLORS AND SPECIFICATIONS MAY VARY FROM ACTUAL PRODUCT. MUSIC GROUP PRODUCTS ARE SOLD THROUGH AUTHORIZED FULLFILLERS AND RESELLERS ONLY. FULLFILLERSAND RESELLERS ARE NOT AGENTS OF MUSICGROUP AND HAVE ABSOLUTELY NO AUTHORITY

4 MULTIGATE PRO XR4400 User Manual

1. Introduction

With the BEHRINGER MULTIGATE PRO you purchased a dynamics processor of the high-end class designed to meet highest requirements: professionalrecording, broadcast and television studios, CD and digital production facilities, etc. Its complete range of features and innovative circuit topology make the MULTIGATE PRO an all-purpose device for reducing noise in audio recordings, forautomatically muting stage mics, expanding the dynamic range of compressed recordings, improving the signal-to-noise ratio of noisy communications systems and for producing special eects, etc.

Future-oriented BEHRINGER technology

Our MULTIGATE range of devices has been a hit ever since we introduced our rst model several years ago. This expander/gate is based on many years of experience and ndings in psychoacoustics and is used throughout the world in renowned studios, sound reinforcement systems as well as in broadcast and television studios.

It was a real challenge to improve the well-known MULTIGATE even further, and we are proud of our success. Compared to its predecessor models, the MULTIGATE PRO not only has additional features, but also comes with dramatically improved functionalities. For example, it now has a parametric lter enabling you to accurately set the trigger frequencies, while the FlexLink system allows for great exibility when linking the device’s individual channels in a master/slaveconguration.

Basically, quadruple gates are not a new invention. However, packing four simple noise gates into one enclosures usually means a compromise in terms of ease of operation and func tionality. Too many control elements make such a device impossible to handle, and if you sacrice crucial functions for the sake of easy operation, the range of useful applications is restricted considerably.

The BEHRINGER MULTIGATE PRO is a quadruple expander/gate with a maximum of functionalities and can still be operated conveniently. Interactive functions make it easy and ecient to specically process any kind of program material, while the need for “adjustment work” has been reduced drastically. Each of the MULTIGATE PRO’s four sections comprises an ultra-fast gate, a programdependent expander, a lter section and high-precision meters indicating both threshold point and gain reduction.

The IAC circuit (Interactive Attack Control)

One of the MULTIGATE PRO’s most outstanding features is the program-dependent control of attack times. The new IAC circuit (Interactive Attack Control) analyzes the program material to calculate the attack time by way of interac tion, so that the hold/release process is triggered automatically depending on the program, which is why the MULTIGATE PRO does not need a dedicated attack control.

Switchable gate/expander function

Another highlight of the MULTIGATE PRO is the switchable operating mode of gate and expander. With the MODE func tion o, the MULTIGATE PRO works in gate mode using an extremely fast attack time to gate all kinds of drum and synthesizer sounds, without cutting their percussive edge.

In expander mode the device analyzes the shape and dynamic contents of the input signal to calculate the control time parameters. It thus works as an interactive expander that adapts automatically to the program signal. The result: guitar sounds, vocals and complex mix signals can be “cleaned” without audible clicks, breathing or other detrimental eects. Additionally, you can freely expand any type of program material in its dynamic range.

Side-chain lter section

When several microphones are used, for example to pick up a drum set, crosstalk between microphones can lead to unwanted triggering of the gate. The built-in parametric sidechain lter of the MULTIGATE PRO allows the user to accurately

select the frequencies causing the trouble, so that the device responds to these frequencies only. The monitor function can be used to pre-monitor the lter, making it easier to adapt the circuitry to the acoustic proper ties of the programmaterial.

FlexLink system

An innovative couple function gives you great exibility to synchronize the expander/gate sections in a master/slave conguration.

◊ The following operational manual will introduce you to the BEHRINGER

MULTIGATE PRO and its various functions. After reading the manual carefully, make sure it is always on hand for future reference.

1.1 Technical background

By employing current modern analog technology it is possible to manufacture audio equipment with a dynamic range of up to 130 dB. In contrast to analog techniques, the dynamic range of digital equipment is approximately 25dB less. With conventional record and tape recorder technology, as well as broadcasting, this value is further reduced. Generally, dynamic restrictions are due to noisy storage in transmission media and also the maximum headroom of thesesystems.

1.1.1 Noise as a physical phenomenon

All electrical components produce a certain level of inherent noise. Currentowing through a conductor leads to uncontrolled random electron movements. For statistical reasons, this produces frequencies within the whole audio spectrum. If these currents are highly amplied, the result will be perceived as noise. Since all frequencies are equally aected, we term this white noise. It is fairly obvious that electronics cannot function without components. Even if special low-noise components are used, a certain degree of basic noise cannot be avoided.

This eect is similar when replaying a tape. The non-directional magnetic particles passing the replay head can also cause uncontrolled currents and voltages. The resulting sound of the various frequencies is heard as noise. Even the best possible tape biasing can “only” provide signal-to-noise ratios of about 70 dB, which is not acceptable today since the demands of listeners have increased. Due to the laws of physics, improving the design of the magnetic carrier is impossible using conventional means.

1.1.2 What are audio dynamics?

A remarkable feature of the human ear is that it can detect the most wide ranging amplitude changes—from the slightest whisper to the deafening roar of a jet-plane. If one tried to record or reproduce this wide spectrum of sound with the help of ampliers, cassette recorders, records or even digital recorders (CD, DAT etc.), one would immediately be restricted by the physical limitations of electronic and acoustic sound reproduction technology.

The usable dynamic range of electro-acoustic equipment is limited as much at the low end as at the high end. The thermal noise of the electrons in the components results in an audible basic noise oor and thus represents the bottom limit of the transmission range. The upper limit is determined by the levels of the internal operating voltages; if they are exceeded, audible signal distortion is the result. Although in theory, the usable dynamic range sits between these two limits, it is considerably smaller in practice, since a certain reserve must be maintained to avoid distortion of the audio signal if sudden level peaks occur. Technically speaking, we refer to this reserve as “headroom”— usually this is about 10 - 20 dB. A reduction of the operating level would allow for greater headroom, i.e. the risk of signal distortion due to level peaks would be reduced. However, at the same time, the basic noise oor of the program material would be increased considerably.

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P/dB

140

120

100

Ear

Fig. 1.1: The dynamic range c apabilities of va rious devices

Microphone Ampliﬁer

Power Ampliﬁer

Tape Radio

Radio

Cassette

Recorder

It is therefore useful to keep the operating level as high as possible without risking signal distortion in order to achieve optimum transmission quality.

It is possible to further improve the transmission quality by constantly monitoring the program material with the aid of a volume fader, which manually levels the material. During low passages the gain is increased, during loud passages the gain is reduced. Of course it is fairly obvious that this kind of manual control is rather restrictive; it is dicult to detect signal peaks and it is almost impossible to level them out. Manual control is simply not fast enough tobesatisfactory.

P/dB

+20

-20

-40

-60

-80

Fig. 1.2: The interactive relationship between the operating level and the headroom

Headroom

Effective SNR

Clipping

Operating level

Noise floor

The need therefore arises for a fast acting automatic gain control system which will constantly monitor the signals and which will always adjust the gain to maximize the signal-to-noise ratio without incurring signal distortion. Thisdevice is called a compressor or limiter.

1.1.3 Compressors/Limiters

The principal function used in these devices is dependent on an automatic gain control as mentioned in the previous section, which reduces the amplitude of loud passages and therefore restricts the original dynamics to a desired range. This application is particularly useful in microphone recording techniques, tocompensate for level changes which are caused by varying microphone distances. Although compressors and limiters perform similar tasks, oneessential point makes them dierent: Limiters abruptly limit the signal above a certain level, while compressors control the signal “gently” over a wider range. Alimiter continuously monitors the signal and intervenes as soon as the level exceeds a user-adjustable threshold. Any signal exceeding this threshold will be immediately returned to the adjusted level.

A compressor also monitors the program material continuously and has a certain threshold level. With compression, in contrast to the action of a limiter, signalsare not reduced in level abruptly once the threshold has been exceeded, but are returned to the threshold gradually. The signal is reduced in gain, relativeto the amount the signal exceeds this point.

Generally, threshold levels for compressors are set below the normal operating level to allow for the upper dynamics to be musically compressed. For limiters, the threshold point is set above the normal operating level in order to provide reliable signal limiting, to protect subsequent equipment from signal overload.

1.1.4 Expanders/Noise gates

Audio, in general, is only as good as the source from which it was derived. Thedynamic range of signals will often be restricted by noise. Synthesizers,eects devices, guitar pickups, ampliers etc. generally produce a high level of noise, hum or other ambient background hiss, which can disturb the quality of the program material.

Normally these noises are inaudible if the level of the desired signal lies signicantly above the level of the noise. This perception by the ear is based on the “masking” eect: noise will be masked and thus becomes inaudible as soon as considerably louder sound signals in the same frequency band are added. Nevertheless, the further the level that the desired signal decreases, the more the noise oor becomes a disturbing factor. Expanders or noise gates oer a solution for this problem: these devices attenuate signals when their amplitudes drop, thereby fading out the background noise. Relying on this method, gaincontrolling ampliers, like expanders, can extend the dynamic range of a signal and are therefore the opposite of a compressor.

In practice, it is shown that an expansion over the entire dynamic range is not desired. With an expansion ratio of 1:5 and a processed dynamic range of 30 dB, an output dynamic range of 150 dB will be the result, exceeding all subsequent signal processors, as well as human hearing. Therefore, the amplitude control is restricted to signals whose levels are below a certain threshold. Signalsabove this threshold pass through the unit unchanged. Due to the continuous attenuation of the signals below this threshold, this kind of expansion is termed “downward” expansion.

The noise gate is the simplest form of an expander: in contrast to the expander, which continuously attenuates a signal below the threshold, the noise gate cuts o the signal abruptly. In most applications this method is not very useful, sincethe on/o transition is too drastic. The onset of a simple gate function appears very obvious and unnatural. To achieve inaudible processing of the program material, it is necessary to be able to control the signal’s envelopeparameters.

By measuring the dynamic range of musical instruments in live recording situations, you will nd that extreme amplitudes occur which often lead to overload in subsequent signal processing equipment. Especially in broadcasting and record cutting techniques, these signal peaks can lead to heavy distortion. To avoid this kind of distortion or, for example, to avoid loudspeakers being damaged by overload, Compressors or Limiters are used.

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