COMPOSER PRO MDX2200
FOREWORD
Dear Customer,
Welcome to the team of COMPOSER 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 COMPOSER 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 COMPOSER PRO” has made it all possible. Everybody
has made very personal contributions, starting from the designers of the unit via the many staff members in my
company to you, the user of BEHRINGER products.
My friends, it’s been worth the trouble!
Thank you very much,
Uli Behringer
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COMPOSER PRO MDX2200
COMPOSER® PRO
Interactive 2-channel expander/gate/compressor/limiter of the reference class
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IKA (Interactive Knee Adaptation) compressor concept combines the advantages of “hard knee” and “soft
knee” characteristics
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Attack and release times controllable automatically or manually
Switchable high-pass filter in control signal path avoids low-frequency signals from dominating compressor
action
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Compression characteristics switchable between IKA and “hard knee” characteristics
IRC circuit in expander/gate allows for “inaudible” elimination of disturbing noise signals
IGC (Interactive Gain Control) peak limiter combines clipper with program limiter circuits
Extremely low-noise operational amplifiers and high-grade VCA’s
High-quality detent 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
Traffic-light function for easy threshold setting
Switchable side chain input with side chain monitor function
Operating level switchable from +4 dBu to -10 dBV
Servo-balanced inputs and outputs featuring 6.3 mm TRS and XLR connectors
High-grade output transformer BEHRINGER OT-1 can be retrofitted
Relay-controlled hard-bypass switch with auto-bypass function (failsafe relay)
Manufactured under ISO9000 certified management system
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COMPOSER PRO MDX2200
TABLE OF CONTENTS
1. INTRODUCTION.....................................................................................................................7
1.1 Before you begin ............................................................................................................................. 8
1.2 Design concept ............................................................................................................................... 8
1.2.1 High quality components and design..................................................................................... 8
1.2.2 Failsafe relays ...................................................................................................................... 8
1.2.3 Balanced inputs and outputs................................................................................................. 8
1.2.4 Transformer balanced outputs (optional) ................................................................................ 9
2. CONTROL ELEMENTS .........................................................................................................9
2.1 Expander/gate section .................................................................................................................... 9
2.2 Compressor section ...................................................................................................................... 10
2.3 Peak limiter section .......................................................................................................................11
2.4 Rear panel control elements of the COMPOSER PRO .................................................................. 12
3. TECHNICAL BACKGROUND ..............................................................................................12
3.1 Noise as a physical phenomenon.................................................................................................. 12
3.2 What are audio dynamics? ........................................................................................................... 13
3.3 Compressors/limiters .................................................................................................................... 14
3.4 Expanders/noise-gates ................................................................................................................. 14
4. APPLICATIONS .....................................................................................................................15
4.1 Compression/levelling/limiting/clipping ........................................................................................... 15
4.2 Expander/gate section .................................................................................................................. 16
4.2.1 Controlling leakage in the studio ......................................................................................... 17
4.2.2 Initial settings for the expander/gate section ....................................................................... 17
4.2.3 Reducing leakage in stage mics ......................................................................................... 18
4.2.4 Reducing feedback in stage mics ....................................................................................... 18
4.2.5 Noise reduction on effects paths ......................................................................................... 18
4.2.6 Creative use of the expander/gate section ........................................................................... 18
4.3 Compressor section ...................................................................................................................... 18
4.3.1 Initial settings for the compressor section ........................................................................... 19
4.3.2 The COMPOSER PRO as a sound effects unit ................................................................... 20
4.3.3 The “muffling” effect of a compressor ................................................................................... 20
4.4 Peak limiter section ...................................................................................................................... 20
4.4.1 Initial settings for the peak limiter section ........................................................................... 21
5. SPECIALAPPLICATIONS.....................................................................................................21
5.1 Using the COMPOSER PRO for recording and cassette duplication ............................................. 21
5.1.1 The COMPOSER PRO in digital recording and sampling .................................................... 22
5.1.2 The COMPOSER PRO in mastering ................................................................................... 22
5.2 The COMPOSER PRO as a protective device ............................................................................... 22
5.2.1 Protection of a system with a passive crossover ................................................................. 23
5.2.2 Protection of a system with an active crossover .................................................................. 23
5.2.3 Improving the sound of a processor system ........................................................................ 23
5.3 The COMPOSER PRO in broadcast ............................................................................................. 23
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COMPOSER PRO MDX2200
6. EXTERNAL SIDE CHAIN APPLICATIONS...........................................................................24
6.1 The side chain function ................................................................................................................. 24
6.2 Using an equalizer in the side chain path ..................................................................................... 24
6.2.1 The COMPOSER PRO as a “de-esser” ............................................................................... 24
6.2.2 Frequency-selective filtering of unwanted signals ................................................................ 25
6.2.3 Suppressing instruments during recording........................................................................... 25
6.2.4 Emphasizing musical instruments during recording............................................................. 25
6.3 Anticipated compression............................................................................................................... 25
6.4 “Voice-over” compression (“ducking”) ............................................................................................. 26
6.5 Triggering additional sounds from a rhythm track........................................................................... 26
7. INSTALLATION .....................................................................................................................26
7.1 Rack mounting.............................................................................................................................. 26
7.2 Audio connections ........................................................................................................................ 26
7.3 Selecting the operating level.......................................................................................................... 27
8. SPECIFICATIONS ..................................................................................................................28
9. WARRANTY ...........................................................................................................................30
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COMPOSER PRO MDX2200
1. INTRODUCTION
In purchasing the new COMPOSER PRO MDX 2200, 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 peak limiter. The
precision and flexibility of the functions are the main outstanding features of this high end unit.
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 side-chain path, gives the user
unsurpassed creative flexibility when processing sound.
Advanced BEHRINGER technology
Compared to its predecessors, the COMPOSER PRO offers several advanced features such as the extended
LED meters for ease of operation when setting the threshold, the adjustable expansion ratio in the expander/
gate section and the side chain filter. Additionally, we have succeeded in refining the audio properties as well
as the circuit topology.
For the first time, the COMPOSER PRO MDX 2200 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.
IKA (Interactive Knee Adaption) 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.
With its IKA circuit the COMPOSER PRO is capable of delivering outstanding musical results both in studio
and live PA applications.
Additionally, the COMPOSER PRO’s side-chain 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 inappropri-
ate. 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 COMPOSER 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 COMPOSER PRO expander/
gate section can be used as an independent unit to eradicate noise offering almost limitless possibilities within
this application.
IGC (Interactive Gain Control) peak limiter
A further remarkable feature of the BEHRINGER COMPOSER PRO is the IGC (Interactive Gain Control)
limiter, an intelligent combination of a clipper and a program limiter. Above an adjustable threshold the peak
limiter begins to function and restricts signal peaks radically (clipper). If however, the threshold of the limiter
was surpassed for more than a few milliseconds, the IGC circuit automatically kicks in and reduces the level
of the overall output signal so that no audible distortion occurs (program limiter). After the level falls below the
threshold, the signal returns to the original value after a period of about 1 second. This IGC circuit proves to be
extremely valuable as much for live work (loudspeaker protection) as for digital situations, where any extreme
signal peaks would exceed the maximum headroom and therefore would cause severe problems. The following
instructions should initially familiarize you with the special terms used, 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. INTRODUCTION
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COMPOSER PRO MDX2200
1.1 Before you begin
The BEHRINGER COMPOSER PRO MDX2200 was carefully packed in the factory, in order to ensure safe
transport. Nevertheless, should the box show signs of damage please check the equipment itself immediately
for any signs of external damage.
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If the unit is damaged, please do not return it to us, 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.
Be sure that there is enough space around the unit for cooling and please do not place the COMPOSER PRO
on high-temperature devices such as power amplifiers, etc. to avoid overheating.
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Before connecting the COMPOSER PRO to the mains, please carefully check that your
equipment is set to the correct supply voltage!
The fuse holder on the female mains connector has 3 triangular markings. Two of these triangles are opposite
each other. The MDX2200 is set to the operating voltage shown next to these markings. It can be set to another
voltage by turning the fuse holder through 180°. CAUTION: this does not apply to export models, which
were designed e.g. only for a mains voltage of 115 V!
Connection to the mains is made by means of a mains cable with an IEC receptacle which complies with the
appropriate safety regulations.
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Please note that all units must be grounded properly. For your own safety, you should never
remove any ground connectors from electrical devices or power cords or render them in-
operative.
1.2 Design concept
1.2.1 High quality components and design
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 COMPOSER PRO, are
exceptional. They boast extreme linearity and very low distortion characteristics. The most important aspect of
the COMPOSER 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
tolerance resistors and capacitors, detent potentiometers, gold plated relay contacts and several other
stringently selected elements.
For the first time, the COMPOSER PRO MDX 2200 uses SMD technology (Surface Mounted Device). These
sub-miniature components known from aerospace technology allow for an extreme packing density, plus the
unit’s reliability could be improved. Additionally, the unit is manufactured in compliance with a ISO9000
certified management system.
1.2.2 Failsafe relays
Failsafe relays have been incorporated into the design of the BEHRINGER COMPOSER PRO, which
automatically and silently bypass the unit in the event of power supply disconnection or failure. These relays
are also active at switch-on to isolate the COMPOSER PRO until the power rails have settled, thus preventing
the possibility of a potentially damaging switch-on thump.
1.2.3 Balanced inputs and outputs
As standard, the BEHRINGER COMPOSER PRO is installed with electronically servo-balanced inputs and
outputs. The new circuit design features automatic hum and noise reduction for balanced signals and thus
allows for trouble-free operation, even at high operating levels. Externally induced mains hum etc. will be
effectively suppressed. The automatic servo-function recognizes the presence of unbalanced connectors and
adjusts the nominal level internally to avoid level differences between the input and output signals (correction
6 dB).
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1. INTRODUCTION
COMPOSER PRO MDX2200
1.2.4 Transformer balanced outputs (optional)
In contrast to electronic balancing, the use of transformer-balanced outputs offers the advantage of galvanic
separation between units. Electrical potential differences and ground loops in audio installations do not there-
fore impair the performance of the units. The transformer-balanced outputs, commonly used in radio and TV
engineering, can also be fitted retrospectively upon request. The BEHRINGER transformer OT-1 is designed to
the highest exacting standards and is available as an accessory.
2. CONTROL ELEMENTS
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Fig. 2.1: COMPOSER PRO front panel
The BEHRINGER COMPOSER PRO has two identical channels. Each channel is equipped with eight backlit
push-buttons, eight rotary controls and 30 LED’s. The COUPLE switch is for stereo operation:
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By engaging the COUPLE switch the COMPOSER 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 a result, the controls of channel 1 take over the functions of
channel 2.
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Should you wish to use the SC EXT function in stereo mode, then be sure that both SC RETURN
connectors 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
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Use the THRESHOLD control to determine the threshold point below which expansion occurs. The
range of this control is from OFF to +15 dB.
2. CONTROL ELEMENTS
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COMPOSER PRO MDX2200
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The RATIO control is used to adjust the expansion ratio when the signal drops below the threshold
value. This control determines whether the unit works as an expander (low ratio level) or as a gate (1:8).
The expansion ratio can be set from 1:1 to 1:8.
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When a signal below 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.
2.2 Compressor section
Fig. 2.3: Control elements of the compressor section
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The THRESHOLD control sets the threshold point for the compressor section. It has a range of -40 to
+20 dB. The “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
THRESHOLD-LEDs show the actual state of the input signal relative to the THRESHOLD setting. The
IKA-“soft knee” range is indicated by the middle yellow LED.
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The RATIO control determines the ratio between the input and output level for all 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 ex-
ceeds the threshold. This control can be adjusted from 1 to 150 milliseconds.
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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 5 seconds.
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By activating the AUTO switch, the ATTACK and RELEASE controls are disabled and the attack and
release rates are automatically derived from the programme material. This function allows for unobtru-
sive musical compression of signals or mixes with widely varying dynamics. Only if set to “MANUAL”
will the settings of the attack and release controls function.
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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.
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Please note when using the THRESHOLD control of the peak limiter section, that the OUTPUT
control of the compressor section precedes the peak limiter section. If the OUTPUT control is
set too high, this can result in continuous peak limiting (see item 19 “THRESHOLD control”).
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When activated, the SC EXT switch severs the connection between the audio input and the side chain
path, whilst at the same time allowing an external signal to be sourced at the SC RETURN jack on the
rear panel.
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2. CONTROL ELEMENTS
COMPOSER PRO MDX2200
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Using the SC MON switch will enable you to connect the side chain 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
side chain signal that is returned via inserted equalizers or other external processors. The SC MONITOR
function will assist you with tuning equalizer parameters for example.
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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.
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The IN/OUT switch activates the relay and hence the corresponding channel. This switch acts as a so-
called “hard-bypass” relay, which means that when the switch is OUT or when the unit is disconnected
from the mains, 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.
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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 should be more or less inaudible.
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The SC FILTER switch activates a high-pass filter in the side-chain path and thus limits the influence of
low frequencies on the COMPOSER PRO’s control processes.
The 12-digit GAIN REDUCTION meter indicates how effectively the gain is reduced by the compressor,
within a range from 1 to 30 dB.
The 12-digit INPUT/OUTPUT LEVEL meter informs you—depending on the setting of the I/O METER
switch—about the current input or output level, within a range from -30 to +18 dB. When the switch is
set to IN (engaged), the meter reads the input level, when it is OUT (not engaged), the output level is
displayed. The meter is referenced to the operating level (-10 dBV or +4 dBu) adjusted with the
OPERATING LEVEL switch.
2.3 Peak limiter section
Fig. 2.4: Control elements of the peak limiter section
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The peak limiter limits the signal to a level adjusted with the THRESHOLD control. Owing to its
extremely fast response (“zero” attack), the limiter is capable of limiting signal peaks without audible
distortion. Whenever the signal is limited for more than 20 ms, the overall level is reduced for about
1 second to avoid heavy and thus audible signal distortion.
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When you use the peak limiter as a protective device against signal peaks, the THRESHOLD
control should be set in combination with the OUTPUT control in the compressor section so
that the peak limiter responds rarely or not at all. Thus, only real signal peaks will activate the
limiter circuit. However, to produce creative sound effects, the peak limiter can be
deliberately set to lower levels.
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The LIM LED lights up as soon as the limiter function is activated.
2. CONTROL ELEMENTS
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COMPOSER PRO MDX2200
2.4Rear panel control elements of the COMPOSER PRO
Fig. 2.5: Control elements of the rear panel
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SERIAL NUMBER. Please take the time to complete and return the warranty card within 14 days of the
date of purchase, otherwise you will lose the right to the extended warranty. Or just use our online-
registration (www.behringer.com).
FUSE HOLDER/VOLTAGE SELECTOR. Before connecting the equipment to the mains supply, please
check that the voltage display conforms with your mains voltage supply. When replacing the fuse, make
sure you use another one of the same type. With many units the fuse holder can be set in one of two
positions, in order to switch between 230 V and 115 V. Please note: if you wish to operate a unit outside
Europe, then a stronger fuse must be used.
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MAINS CONNECTION. Use the enclosed power cord to connect the unit to the mains. Please also note
the instructions given in the chapter 7. “INSTALLATION”.
AUDIO IN. These are the audio inputs of your COMPOSER PRO, available both as balanced 6.3 mm
jack and XLR connectors.
AUDIO OUT. These are the audio outputs of your COMPOSER PRO. Matching phone jack and XLR
connectors are wired in parallel. These outputs can be transformer-balanced by retrofitting the optional
output transformer OT-1.
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With the OPERATING LEVEL switch you can adapt the COMPOSER PRO to various operating levels,
i.e. you can select both the -10 dBV home recording level and the professional studio level of +4 dBu.
The level meters are referenced automatically to the selected level, i.e. an optimum operating range of
the meters will always be ensured.
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SC SEND. This is the unbalanced side-chain output which allows for routing the audio signal to external
processing devices.
SC RETURN. This is the unbalanced side-chain input used to return any external or processed control
signal.
3. TECHNICAL BACKGROUND
By employing current modern analog technology it is possible to manufacture audio equipment with a dynamic
range of up to 125 dB. In contrast to analog techniques, the dynamic range of digital equipment is approxi-
mately 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.
3.1 Noise as a physical phenomenon
All electrical components produce a certain level of inherent noise. Current flowing 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 amplified, the result will be perceived as noise. Since all
frequencies are equally affected, 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 effect is similar when replaying a tape. The non-directional magnetic particles passing the replay head can
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3. TECHNICAL BACKGROUND
COMPOSER PRO MDX2200
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.
3.2 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 amplifiers, 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 floor and thus repre-
sents 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 floor of the program material would be increased considerably.
P/dB
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120
100
80
60
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Fig. 3.1: The dynamic range capabilities of various devices
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 difficult to detect signal peaks and it is almost impossible to level them out. Manual control is
simply not fast enough to be satisfactory.
3. TECHNICAL BACKGROUND
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COMPOSER PRO MDX2200
P/dB
Clipping
+20
Headroom
0
-20
-40
-60
-80
Operating level
Effective SNR
Noise floor
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Fig. 3.2: The interactive relationship between the operating level and the headroom
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. This system is a part of the COMPOSER PRO.
3.3 Compressors/limiters
By measuring the dynamic range of musical instruments in live recording situations, you will find 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.
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 different: 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 com-
pression, 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.
3.4Expanders/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, effects devices, guitar pickups, amplifiers 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 significantly above the level of the
noise. This perception by the ear is based on the “masking” effect: noise will be masked and thus becomes
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3. TECHNICAL BACKGROUND
COMPOSER PRO MDX2200
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 floor becomes a disturbing factor.
Expanders or noise-gates offer a solution for this problem: these devices attenuate signals when their ampli-
tudes drop, thereby fading out the background noise. Relying on this method, gain controlling amplifiers, 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 5:1 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 off the signal abruptly. In most applications this method is not
very useful, since the on/off 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. This is part of the many features of the COMPOSER PRO.
4. APPLICATIONS
In this section, several typical applications of the BEHRINGER COMPOSER PRO are discussed. The follow-
ing basic settings can resolve most dynamic problems. They are the ideal starting point. Please take the time
to study the application examples carefully, in order to be able to make full use of the COMPOSER PRO’s
capabilities in the future.
Main Applications And Initial Settings
The main applications of the COMPOSER PRO can be divided into three categories:
1. The EXPANDER/GATE section is used to eliminate interference and to suppress background noise and
leakage on individual tracks in multitrack recording.
2. The COMPRESSOR section is used to compress the program material and to create special effects and
unusual sounds, which are used for recording and musical performance.
3. The subsequent PEAK LIMITER section is designed to protect loudspeakers, tape recorders, transmitters
etc. from being overloaded.
4.1 Compression/levelling/limiting/clipping
Now that the functions of the individual sections have been clearly explained, we would like to acquaint you
with more terms and relationships of the dynamics process.
Compression
A compressor converts a large dynamic level into a restricted range. The extent of the resulting dynamic level
is dependent on the threshold, attack, release and ratio settings. As it is the desired effect of a compressor to
increase a low level signal, generally the threshold is set low. The “inaudible” compression mode requires fast
attack and release times and low ratios. The faster the chosen control times and the higher the compression
ratio, the greater the effect on the short term dynamics. This fact is often used to achieve audible and creative
sound effects.
Levelling
The levelling mode is used to keep output level constant, i.e. to compensate for long term gain changes,
without affecting the short term dynamics. Normally, the threshold is set quite low in order to be able to
increase low level signals. Levelling requires slow attack and release times, combined with a high ratio. Be-
cause of the very slow response time, levelling has no effect on signal peaks or short term changes in average
level.
Limiting
The limiting function requires a fast attack time and a high ratio and release time setting, which is dependent
on the specific use and the desired sound effect. As it is usually the task of a limiter to limit only high signal
peaks, the threshold is usually set at a high level. The dynamics are reduced dependent on the ratio setting
and the degree by which the threshold point was exceeded. If the attack time is adjusted to control only the
4. APPLICATIONS
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COMPOSER PRO MDX2200
average level without affecting signal peaks above the threshold, this is referred to as the program limiter. For
this purpose the attack time will be set above 20 ms. If the attack time is further reduced in order to also control
signal peaks, this is defined as the peak limiter.
Clipping
In contrast to the two previously mentioned limiters, the clipping mode features infinitely fast control times, an
infinite compression ratio and creates an unsurpassable barrier (“brickwall”) for all signals above a certain level.
To be able to control the signal peaks, the clipping function radically cuts signals above the threshold, without
affecting the amplitude of the original signal. If used in normal applications, this function remains inaudible and
under certain circumstances it can even lead to an improved sound, because cutting the transients creates
artificial harmonics. If misused, clipping can cause very obvious and distasteful distortion, which in an extreme
manner, will convert the signal’s waveform into a square wave signal. This effect is often produced in guitar
distortion devices (“fuzz boxes”).
4.2 Expander/gate section
The main task of the expander/gate is to “inaudibly” eliminate undesirable background noise from the usable
signal. As already described in chapter 3.4, a downward expander automatically reduces the overall level for all
signals below an adjustable threshold. The expander therefore operates in opposite way to that of a compres-
sor/limiter. Expanders generally function with a flat ratio curve, so that the signal continually fades. Noise-
gates however, can be seen as “high ratio” expanders. If the signal falls below the threshold, it is radically
attenuated.
The BEHRINGER COMPOSER PRO is equipped with a newly developed IRC (Interactive Ratio Control) Ex-
pander, the ratio of which is automatically adjusted dependent on the program material. The response charac-
teristics of conventional expanders tend to cut into the signal abruptly and the result of this is unacceptable
most of the time. Gain changes become audible.
The IRC Expander is therefore equipped with a soft, interactive non-linear ratio curve, which is best suited to
human hearing. Critical signals in the vicinity of the threshold level are processed with a minute expansion
ratio, whereas signals that reduce in level will be subjected to an increasingly higher ratio, which will result in
greater attenuation.
Output
Gain 0 dB
Threshold
IRC-Curve
Expander, 1:8
Noise Gate, 1:oo
Input
Fig. 4.1: IRC curve characteristic of the Expander
The result is expansion, which is less critical to adjust and which is more tolerant of useable signals, whose
level is slightly above that of the noise floor. Expansion therefore occurs extremely “soft” with low ratio settings,
while the known negative effects of expansion are inaudible. The attack time of the IRC expander is set
automatically and program-dependent, i.e. extremely short for quickly changing signals and slower for a more
balanced program material. Since the expander/gate adapts itself automatically to the program material, you
will note that the new IRC (Interactive Ratio Control) circuit produces considerably better results than conven-
tional expanders.
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COMPOSER PRO MDX2200
4.2.1 Controlling leakage in the studio
Expander/gates are most commonly used to suppress undesirable leakage of sound from one track to another
during recording or playback. They are usually used when recording drum kits, where the mics are very close
to each other. High volume levels of individual instruments often cause considerable leakage onto all the
adjacent mics and results in conflicting frequency and phase coherence problems, as well as unspecified
sounds (“comb” filter effects). It is vitally important that every instrument is recorded into a separate mic and
that each mic is individually gated.
Patch the MDX2200 into a snare drum channel for example and adjust it so that triggering only occurs on snare
hits. Each mic should be set to its maximum operating level, monitored (see SC MON switch) and the
THRESHOLD level set so that each snare hit sounds acoustically clean and seperate, as though it was played
on its own.
The optimum use of the expander/gate depends principally on microphone technique. Be particularly careful,
when high frequency instruments are located to the side or rear of a cardioid microphone. Most cardioids
exhibit a sharply rising off-axis response characteristic at higher frequencies. If there is only a 2 or 3 dB
difference between the on-axis and off-axis response in the 5 to 10 kHz region, cymbals may leak excessively
into the tom mics and you may have hi-hat spilling all over the snare mic.
Please make full use of the directional characteristic of the mics, to acoustically exclude all other instruments
as much as possible. Make sure that you do everything possible to achieve source separation with good
microphone technique. Otherwise the expander/gate is not able to undertake clear acoustic separation.
Sometimes, it is necessary to prevent the expander/gate from responding to low frequencies (rumbles etc.),
especially if a singer is moving the microphone around on a mic-stand. More information about this topic in
chapter 6.2.
4.2.2 Initial settings for the expander/gate section
Control
Setting
OFF
THRESHOLD control
RELEASE switch
RATIO control
SLOW
1:2
Tab. 4.1: Initial settings for the expander/gate section
Begin with very low threshold levels, so that the signal can pass through the unit unaffected. Now turn the
control clockwise until all unwanted noise is removed and only the sound of the desired instrument can be
heard.
To adapt the unit to the program material properly, you can additionally choose between a SLOW or FAST
release time. In the depressed position, the unit works at a slow release time. Percussive material with little or
no reverb, is processed in fast mode, whereas the slow mode is advantageously used for signals with long
durations or signals with heavy ambience. You will find that a fast release time (FAST mode) is preferable for
acoustic separation of most percussive sounds, whilst cymbals and tom toms, normally benefit from the
SLOW mode.
The RATIO control determines the ratio between input and output level, for all signals below the selected point
of threshold. Use this control to determine whether the section works as an expander or as a gate (Ratio 1:8).
If the controls are set correctly, the drum sounds will be “dry”, “sharp” and clearly defined. If you do not have
enough mics (or COMPOSER PRO channels!) to record each instrument separately, try to create sub-groups:
put the snare and mid-toms together, and group the side-toms, bass drum and cymbals together with the help
of a mixing console.
The aim is to set up the expander/gate and to position the group mics so that each strike on an instrument
opens a specific mic and so only that instrument is recorded, whilst the other mics remain “muted”.
4. APPLICATIONS
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COMPOSER PRO MDX2200
4.2.3 Reducing leakage in stage mics
The COMPOSER PRO has many uses in live-work, on stage and in multi-miking situations: a well set up
expander/gate can effectively suppress background noise, compressor type pumping noise and microphone
leakage etc. without producing any undesirable side effects. Expander/gates are commonly used for process-
ing vocals. When specifically used with a compressor, the distance and position of the mic in relation to the
singer is very critical: the further the distance, the more sensitive the mic is to background noise. Use the
expander/gate section in the slow release mode to “inaudibly” eliminate background noise, that occurs in
pauses between singing. When used in live situations, leakage of miked instrumentation is substantially
reduced, as well as other acoustic contaminants in various recording situations.
4.2.4 Reducing feedback in stage mics
When a singer is using a vocal mic, their voice effectively stops other sounds from entering the mic. But in
pauses between the singing, the mic will pick up noise from the house PA and monitors, which can lead to
unpleasant feedback problems. If the COMPOSER PRO is inserted into the mic channel, it will shut off the
channel when it is not being used, reducing the possibility of feedback. Principally all mics should be included
in this application.
4.2.5 Noise reduction on effects paths
The effects rack is one of the main overlooked sources of noise in a PA system or recording facility. The price
of reverb and delay units and harmonizers has fallen drastically over the last number of years, which have made
these units a common feature in small studios and home recording installations. However, multiple effects
units considerably increase the overall noise level, so that the pleasure in acquiring a new sound effect is short
lived.
It will prove useful to use the BEHRINGER COMPOSER PRO as the last component in the chain of effects
units and use the noise reduction function of the expander/gate section. We recommend that you use a slow
release time in order to maintain the natural reverb.
4.2.6 Creative use of the expander/gate section
In addition to the previously explained applications, the expander/gate can be used to change the sound
characteristics. For example, the quality of ambience or reverberation created by an instrument within a room
can be modified: when an instrument stops decaying, the reverberation of the instrument falls below the user-
defined threshold. The reverberation can be controlled by using the THRESHOLD control and the RELEASE
switch. The decay characteristics of the instrument can be controlled using the release switch, so that the
natural characteristics of the instrument remains. Experiment with the effect, this control has on the decay of
the instrument. In SLOW mode, the signal is gently faded out - in FAST mode, the duration of the reverberation
can be removed completely.
4.3 Compressor section
The task of a compressor is to reduce the dynamic range of program material and to control the overall level.
The extensive controls of the compressor section, provide a great range of dynamic effects: from musical and
soft compression to limiting signal peaks, right up to extreme and effective compression of the overall dynam-
ics. For example, a low ratio and very low threshold setting can be used to achieve soft and musical processing
of the general dynamics of the program material.
Higher ratios, together with low threshold settings, create relatively constant volume (levelling) for instruments
and vocals. High threshold levels generally limit the overall level of a program. Ratios greater than 6:1 effectively
prevent the output level from significantly exceeding the threshold point (provided that the OUTPUT control is in
the 0 dB position).
Please note that the compression of the entire program material (achieved by low threshold settings) sounds
less natural with higher ratio settings. Ratio settings in the range of 4:1 and lower, effect the dynamics of the
program material less and are often used to compress the sound of a bass guitar, a snare drum or a vocal.
Sensitive and moderate settings are generally used in mixing and for levelling of program material in broadcast.
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5. APPLICATIONS
COMPOSER PRO MDX2200
Output
Gain 0 dB
Threshold
Ratio 2:1
Hard Knee
Ratio 4:1
Limiter
oo:1
IKA Curve
green
yellow
red
Input
LED
Fig. 4.2: IKA characteristic of the compressor section
The new IKA (Interactive Knee Adaptation) circuit prevents aggressive compression, created by high ratios,
from sounding too unnatural. This is achieved with an interactive control function, which begins above the
threshold level and introduces a “Soft Knee“ curve characteristic in the range up to 10 dB above the threshold
point. Beyond this range, the signal is subjected to linear (“Hard Knee“) compression.
+
With the threshold control completely turned to the right, the threshold value is +20 dB. Since such a
value will not be reached in practice, you can use it to disable the compressor section and work exclu-
sively with the expander/gate and limiter circuits.
4.3.1 Initial settings for the compressor section
Control
Setting
IN
IN/OUT switch
SC EXT switch
SC MON switch
INTERACTIVE switch
SC FILTER switch
THRESHOLD control
RATIO control
OUT
OUT
IN
OUT
+20 dB
3:1
AUTO switch
IN
OUTPUT control
0 dB
Tab. 4.2: Initial settings for the compressor section
Rotate the THRESHOLD control counterclockwise until an appropriate amount of gain reduction is indicated on
the GAIN REDUCTION meter. This operation will be accompanied by an audible drop in output level. The
OUTPUT control should now be turned clockwise to reinstate the output level. The level of the unprocessed and
the processed signal can be compared by pressing the I/O METER switch and observing the INPUT/OUTPUT
LEVEL meter.
Final adjustments of the controls can then be made to suit your particular requirements, including the RATIO,
ATTACK and RELEASE controls. The AUTO function of the attack and release times, provides program
dependent dynamic processing which suits most standard uses. If a “condensed“ or “wider“ sound processing
4. APPLICATIONS
19
COMPOSER PRO MDX2200
technique is required, the attack and release times can also be manually adjusted.
The experienced user will be in a position to specify parameters while in bypass mode and thus realize the
effect before the unit is actually switched into operation. This is important in live situations, where a signal
needs to be managed efficiently by the engineer, without the convenience of continual A/B comparison.
4.3.2 The COMPOSER PRO as a sound effects unit
In the early 1960’s, musicians began looking at the recording process as a way to create new sounds. The
pumping effect which had been avoided by earlier engineers suddenly became fashionable and was utilized as
a creative tool, laying the groundwork for many of the sounds which are now considered indispensable in
contemporary music. The compressor is used in this role because you can hear it working, and control of the
dynamic range is of secondary importance.
The BEHRINGER COMPOSER PRO, with its extensive range of functions, is well suited to this application.
Sound effects of this kind can be achieved using “extreme” settings. To achieve this, set the THRESHOLD
control to a fairly low level, the RATIO control to almost maximum and use the ATTACK and RELEASE
controls to obtain the desired effect. Experiment with all the controls in order to get a feel of their function!
4.3.3 The “muffling” effect of a compressor
Quite often, compressors are sometimes accused of “muffling” the sound, whilst at the same time reducing the
dynamics. This fact should be investigated further. Bass frequencies contain most of the energy within music
and therefore cause the compressor to reduce the overall dynamics. If the music also contains high frequen-
cies along with the bass frequencies, these are also reduced in level. This is the reason why: in an extremely
compressed recording of drums, the cymbals and high-hats are acoustically swamped by the sound of the
snare or the bass drum. The same effect is experienced when processing reverberated or ambient sounds. The
solution commonly used to this basic problem is either to reduce the compression ratio or to slow down the
attack time, so that the increasing high frequency transients pass through the compressor unhindered before
the compressor takes effect.
The COMPOSER PRO MDX2200 offers a solution to this problem that is by much more elegant. The SC
FILTER switch allows you to activate a high-pass filter in the control signal path of the compressor. This filter
makes sure that midrange and treble range frequencies are taken into account to a greater extent, and that a
low-frequency signal triggers less compression than a midrange/treble signal of comparable level. A major
advantage of this design can be seen in the fact that the frequency response of the overall signal is not modified
below the threshold adjusted with the Threshold control.
In pop music the dynamics of both kick drum and bass guitar are usually processed individually. The side-
chain filter is therefore ideally suited to apply overall compression in the mix-down, to compress the music
while increasing its loudness, but without having to accept the drawbacks described above.
Please note that we offer a whole series of high-grade equalizers and enhancers/exciters, which are perfect
tools to give any dynamics-processed signal the finishing acoustic touch. Please ask for detailed information!
4.4 Peak limiter section
As a section of its own and independent of the remaining control functions, the peak limiter enables you to limit
the maximum peak level on the COMPOSER PRO’s output. It has been designed for use in combination with
the compressor section. Independently of all compressor functions, you can protect subsequent devices against
signal peaks, short-time overload and excess modulation (radio stations, etc.).
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4. APPLICATIONS
COMPOSER PRO MDX2200
Peak Limiting
Level
Program Limiting
Release
Threshold
Input
Output
approx. 1 s
5 ms
20
20 ms
10
30
t/ms
Fig. 4.3: IGC characteristic of the limiter section
The diagram illustrates the functioning of the IGC limiter. The solid graph represents the output signal, while the
dashed graph above shows the input signal response. The areas between the graphs represent the amount of
gain reduction (bright areas are “clipping areas“, i.e. signal peaks are radically cut off, dark areas show the
effect of the program limiter). The limiter is activated when the adjusted threshold is exceeded for more than 20
ms, so as to limit audible clipping to a very short moment. About 1 s after the signals has dropped below the
threshold again, the reduction is set to 0 dB, so that input and output signals are identical again (unity gain).
4.4.1 Initial settings for the peak limiter section
Control
Setting
OFF
THRESHOLD control
Tab. 4.3: Initial settings for the peak limiter section
The THRESHOLD control of the Peak Limiter sets the threshold level, so that subsequent units are protected
from overloading. If the LIM comes on regularly or is on constantly, the OUTPUT control of the Compressor
section must be turned down, as this control sets the level of the signal, which is routed to the Peak Limiter
section.
If this technique leads to an undesired drop in the overall level, it is recommended that you increase the
compression: either, reduce the threshold level, or increase the compression ratio with the RATIO control. The
OUTPUT control will compensate for a renewed drop in level.
5. SPECIAL APPLICATIONS
5.1 Using the COMPOSER PRO for recording and cassette duplication
In the recording and duplication field the goal should always be to achieve an optimum recording level onto the
recording media. Too low or too high recording levels lead to side effects such as noise, distortion etc. In
mastering and multitrack recording, as well as in duplication, one should always take care to utilize the full
dynamic range of the tape recorder, DAT recorder etc. Principally, it is possible to control the recording level by
“riding“ faders, which means with low level signals, the gain is increased, whereas the amplitude of high level
signal is reduced. It is obvious that this method is insufficient because, especially in live recordings, the
expected signal levels cannot be anticipated correctly. Especially with multitrack recordings, which are run
under hectic circumstances, the signal level of all channels cannot be monitored and controlled at the same
time. Generally, with manual control, it is not possible to achieve satisfying recording results.
An automatic gain control system achieves better and more constant results. Use the COMPOSER PRO by
starting with the initial settings, and use its dynamic control functions in order to be able to drive an analogue,
as well as a digital recording, up to the limit of its maximum dynamic range while remaining noise- and
distortion-free.
5. SPECIAL APPLICATIONS
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COMPOSER PRO MDX2200
5.1.1 The COMPOSER PRO in digital recording and sampling
In an analogue recording, too low recording levels lead to an increased noise level, whereas too high levels will
cause a compressed and “squashed” sound. In extreme cases, it will cause distortion due to tape saturation.
In contrast to analogue, side effects in the digital field always become extremely audible: with decreasing level,
a tape previously recorded with insufficient level loses resolution: the recording sounds “hard” and loses “at-
mosphere”. With excessive level, the recording sounds harsh and heavily distorted. In order to avoid these
effects, the Peak Limiter section of the COMPOSER PRO should be placed before for example a sampler. As
a result of this process, a digital recording or a sampling event can be optimally set in level without any
problem.
5.1.2 The COMPOSER PRO in mastering
The mastering process is one of the most critical processing steps in recording. In this production step, it is
the goal to achieve a “maximum level” copy of the recording, without any noise or distortion. In many applica-
tions it is further required to produce a high average volume. In the field of commercial media for example, this
is apparent especially with records and cassettes which are processed with high average volumes. Quite often
in these cases, dynamics suffer drastically, because the program material has been compressed and limited
too heavily. Using the Compressor and the Peak Limiter section of the COMPOSER PRO allows you to
drastically increase the overall volume, without audibly affecting the dynamics.
Proceed as follows:
1. Limit the dynamics of the program material by 6 dB using the Peak Limiter section. By softly clipping just
the transients, the real audio signal will not be limited, resulting in a higher headroom. The overall gain can
now be increased by 6 dB, which leads to a higher volume. More than 6 dB should not be limited, otherwise
side effects could become audible.
2. Therefore, in addition, you should also use compression. It is recommended that the compression is limited
to the “first” 6 dB of the dynamic range only. A high threshold level in addition to the auto mode will give good
results.
This effect is particularly noticeable with DAT recorders, whose level indicators achieve a response time of less
than 1 ms. Set the DAT recorder at unity and now reduce the LEVEL control of the peak limiter until the LIM
LED starts to illuminate. The “cut” signal peaks cause a reduced recording level of about 6 dB, which is visible
on the level indicators of the DAT recorder. Now increase the recording level of the recorder back to unity. The
result is a clearly louder recording without any loss of sound.
5.2 The COMPOSER PRO as a protective device
Sound system distortion is usually a result of amplifiers and loudspeakers being driven beyond their limitations
by signals clipping. The signal limitations that occur lead to unpleasant distortion that is dangerous to the
speakers.
A speaker diaphragm is required to accelerate, slow down, smoothly change direction and accelerate again in
normal operation. Distorted operation (clipping) leads to instant acceleration, instant stop, change of direction
and instant acceleration again. Since speaker diaphragms are subject to the laws of physics, they will not take
this kind of punishment for long: the diaphragm will either break up or its voice coil may overheat.
In addition to the damage caused by sustained overload, the speaker may also be damaged by an occasional
high level overload, e.g. the sound of a microphone falling onto a hard floor. Even if this type of transient does
not destroy a speaker outright, it may damage the speaker surround in such a way, as to cause mechanical
abrasion and future failure. It is recommended that you use the BEHRINGER COMPOSER PRO in order to
protect the speaker. “Brick Wall” peak limiters are not normally necessary for PA systems, as amplifiers and
loudspeakers are tolerant of short signal peaks.
Nevertheless, conventional limiters have to be generally driven far beyond the headroom limit of an amplifier, in
order to limit the level and length of the transients responsible for overloading the system. The disadvantage of
this principle is that the unit’s full range cannot be completely used. If an increase in the average level of up to
3 dB is attained with the COMPOSER PROs IGC peak limiter, this means that you effectively double the power
amplification. The COMPOSER PRO can act in this way to get the power of a 10,000 Watts system (distortion
free) out of a PA system of 5,000 Watts. The following instructions will help you to integrate the unit into your
system.
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5. SPECIAL APPLICATIONS
COMPOSER PRO MDX2200
5.2.1 Protection of a system with a passive crossover
If your sound system incorporates a passive crossover network (included in the loudspeaker case), insert the
BEHRINGER COMPOSER PRO between your mixing console output and the power amplifier input. It is used
as the last link in the chain preceding the power amp. Thus, you can effectively avoid the “technical knockout”
of the midrange/tweeter range caused by high-energy bass signals! This statement, as paradox as it may
seem at first, can be explained with the fact that especially low-frequency signals with high amplitudes can
overload the power supplies in the amplifier(s). The resulting clipping (cutting off of signal peaks) produces
high-energy distortion (upper harmonics), which is abruptly added to the midrange/tweeter signals. For this
reason, “weak” power amps, in particular, must be protected by a limiter in their “input dynamics”.
5.2.2 Protection of a system with an active crossover
For systems using active crossovers, there are two ways to use the BEHRINGER COMPOSER PRO. The unit
may be inserted between the console output and the crossover input. In this application, the BEHRINGER
COMPOSER PRO will process the entire audio frequency spectrum.
Alternately, the BEHRINGER COMPOSER PRO can be inserted between the output of an active crossover
and the input of a power amplifier. In this application it will only affect a specific range of frequencies. This
application is particularly suited to protect the most fragile components of a multi-way speaker system against
harmful signal peaks. For example, when your tweeters keep on going up in smoke all the time, the entire
system should be operated at lower sound pressure levels or the tweeters should be replaced by other models.
Using the COMPOSER PRO in the corresponding tweeter band avoids overloading and thus damage to the
speakers.
5.2.3 Improving the sound of a processor system
A processor system is understood as a PA system which contains a special active crossover whose outputs
are linked via separated power amplifiers to the loudspeakers. Each band has its own limiter whose task it is
to limit dangerous signal peaks to a certain level. This process avoids overloading the subsequent power
amplifier or destruction of the loudspeaker.
In some units, the crossover frequencies in the crossover unit are further changed during high signal levels to
achieve a “loudness contour” suited to the human hearing. But in many cases, this function leads more to a
disturbance than to an improvement of the sound quality.
If the COMPOSER PRO is preceding this system, the signal peaks can be eliminated before they reach the
limiters of the processing system. The sound quality therefore remains natural and free of side effects caused
by the changing frequencies of the crossover.
5.4The COMPOSER PRO in broadcast
The main aim of processing sound recordings for commercial radio and television is to achieve a maximum
transmission volume at all costs. Owners of these radio and television stations strive to get bigger audience
ratings, because principally, radio programs whose reception is louder than the average are preferred by the
listener. By achieving a bigger audience, the broadcast station gains more money from the increasing number
of promotion companies placing adverts.
What is volume?
Volume is defined as the relationship between the average level of program material to peak-to-peak level, in
response to amplitude and duration. The higher the average level and the time it remains at a high level, the
louder the program material will be perceived by the listener.
If you want to run your broadcast station at maximum average volume, proceed as mentioned in chapter 5.1.2.
Please make sure that the maximum peak level is below the threshold of the transmitter’s limiter, otherwise
this could lead to very hard and audible use of the transmisson limiters. Keep in mind that a heavy increase in
average volume by means of compression always leads to a loss in dynamics and an increased perception of
side effects. The moderate use of the compressor and the peak limiter sections of the COMPOSER PRO
result in higher average volumes, free of distortion.
5. SPECIAL APPLICATIONS
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COMPOSER PRO MDX2200
6. EXTERNAL SIDE CHAIN APPLICATIONS
6.1 The side chain function
The BEHRINGER COMPOSER PRO offers an exceptionally usable external facility by using the side chain
function. By activating the SC EXT switch, the COMPOSER PRO’s control path is disconnected from the
audio input and therefore interrupted. The audio input is routed to the SC SEND output and the SC RETURN
input now receives the new control signal which is derived from an inserted effects processor.
Please note the correct wiring for mains powered units in order to avoid ground loops, as the side chain inputs
and outputs are unbalanced. The working level of external units must be at line level (-20 to +10 dBu) and must
be at unity gain.
6.2 Using an equalizer in the side chain path
It is very common to make the response threshold of a compressor frequency-dependent, where a graphic or
parametric equalizer is connected to the side chain path. To retain the threshold setting of the COMPOSER
PRO, unwanted frequencies should be reduced by an equalizer and the desired frequencies should be kept at
the same level. Should for example, the compressor be controlled by a narrow mid-frequency band, it is
advisable to lower the bass and treble controls. The middle frequency control remains at unity gain.
6.2.1 The COMPOSER PRO as a “de-esser”
“De-essing” is a special application of frequency selective compression. A problem often encountered in re-
cording, is the sibilant (Ssss) sound of the human voice. High frequency, sibilant sounds and pops can pro-
duce very high energy levels which can sometimes cause an otherwise normal and undistorted voice to sound
very harsh, shrill and sometimes unintelligible. The solution is frequency conscious compression or limiting.
The unit responds only to selected frequencies and reduces the level temporarily, as soon assibilant sounds or
pops are detected.
If the detector circuit registers an excessive amount of high frequency information within the program material,
as in a normal compressor, the VCA is activated and the overall level is reduced. As this type of compression
affects the whole frequency range, this process is called broadband de-essing.
Please note that this type of frequency selective compression is very different from simple, fixed equalisation
using notch filters, since de-essing has no effect on the signal except at the instant the sibilant occurs. The
general frequency response is principally not affected during this process.
When de-essing, simply insert an equalizer not into the audio path but into the side chain path of the BEHRINGER
COMPOSER PRO. The equalizer is inserted between the SC SEND output and the SC RETURN input of the
BEHRINGER COMPOSER PRO. While the SC EXT switch is depressed, the equalizer is inserted into the
side chain loop and controls the unit. With the help of the side chain monitor function, the centre frequencies
of the equalizer are then adjusted exactly to match the frequencies of the sibilant sounds. All other frequencies
are filtered out, so that with maximum attenuation of these frequency bands, along with a correctly adjusted
threshold point, the unit responds solely to the selected signal being produced by the equalizer. The level of the
sibilant sounds can therefore be effectively limited.
1. Turn the THRESHOLD control anticlockwise until the GAIN REDUCTION meter shows an appropriate drop
in level.
2. Now press the SC MON switch and adjust the equalizer corner frequencies (generally 6 - 10 kHz) by
monitoring, until it is within the range of the sibilance.
3. Release the SC MON switch and recalibrate the THRESHOLD control, so that the unit reacts only when the
sibilant sound occurs.
Level compensation using the OUTPUT control is not necessary. Although the recommended attack and
release times for this function are proven, the time parameters can be adjusted if necessary to achieve maxi-
mum results. The AUTO function should not be used.
24
6. EXTERNAL SIDE CHAIN APPLICATIONS
COMPOSER PRO MDX2200
Control
Setting
IN
SC EXT switch
SC MON switch
INTERACTIVE switch
SC FILTER switch
THRESHOLD control
RATIO control:
OUT
OFF
OUT
+20 dB
1:4
AUTO switch
OUT
1 ms
150 ms
0 dB
ATTACK control
RELEASE control
OUTPUT control
Tab. 6.1: Initial settings for the De-Esser functions
6.2.2 Frequency-selective filtering of unwanted signals
Based on the set-up described in the de-esser section, the unit may also be used to eliminate rumble, hum
and equipment noise (air-conditioning systems, camera noise etc.). Using the SC MON switch, adjust the
frequencies of the equalizer to match the unwanted frequencies and use a peak filter with a high slope. Take
care to decrease the amplitudes of the unrequired frequencies. Proceed now as described in the previous
chapter 6.2.1. This will result in compression of the selected frequencies and thus a decrease in the gain of the
program material.
6.2.3 Suppressing instruments during recording
Another function of the BEHRINGER COMPOSER PRO allows helpful correction of previously recorded mate-
rial. If, for example, an excessively loud bass drum needs to be suppressed, reduce all the equalizers fre-
quency bands above 150 Hz. This setting causes frequency specific compression, which reacts as soon as
increased energy is detected in this band. By increasing the threshold level, the compression can be made to
react only to loud pedal or stick actions. Generally, it can be said that relatively high threshold settings prevent
the overall sound from being impaired and lead to the compression of solo instruments or very loud sounds.
6.2.4 Emphasizing musical instruments during recording
On the other hand, you can use the BEHRINGER COMPOSER PRO to bring out an instrument solo or a lead
vocal in a cluttered mix. Using the SC MON switch, match the frequencies of the equalizer to the frequencies
of the instruments to be emphasized and for this it is best to use a notch filter with a high slope.
Please make sure that in this application, you only reduce the amplitude of the selected frequencies. The
compression results in a subjective decrease in the volume of the overall program material. Only the selected
frequencies coming from the equalizer remain uncompressed and are therefore perceived as being louder. This
inverse type of compression also helps to emphasize instruments during low level passages, so that they
become more pronounced.
6.3 Anticipated compression
If you feed the audio signal directly into the SC RETURN input and send the audio signal through a delay before
the audio input, the BEHRINGER COMPOSER PRO can anticipate the need for gain change. With experimen-
tation, the effect can create a “zero” attack time at a given frequency. Additional delay beyond this “zero”
attack time will produce a special sound effect, similar to the dynamic envelope inversion you may already be
familiar with from reverse tape playback.
6. EXTERNAL SIDE CHAIN APPLICATIONS
25
COMPOSER PRO MDX2200
6.4“Voice-over” compression (“ducking”)
The COMPOSER PRO can be used to automatically reduce music to a background level, when an announcer
is speaking through a microphone. For this purpose, the COMPOSER PRO is used as an automatic fader and
is controlled by the announcer’s microphone, which is connected to the SC RETURN input via a preamplifier.
The music output and the announcer’s voice, are then mixed. This application is known as “voice-over” com-
pression or “ducking” and is commonly used in discos, radio stations etc.
6.5 Triggering additional sounds from a rhythm track
This technique is used to give a rhythm track more “punch”. For this purpose, only the expander/gate section
is required and the compressor and peak limiter sections are switched off. The bass guitar track is connected
to the audio chain of the COMPOSER PRO MDX2200, while the bass drum is connected to the SC RETURN
input. By activating the SC EXT switch, the bass guitar is now triggered by the bass drum.
Another application allows the sound of the bass drum to be supported or extended by other instruments
(synthesizers etc.), where the bass drum is used to trigger a new sound, which is then mixed into the track.
7. INSTALLATION
7.1 Rack mounting
The COMPOSER PRO fits into one standard 19" rack unit of space (1 3/4"). Please allow at least an additional
4" depth for the connectors on the back panel. Be sure that there is enough air space around the unit for
cooling and please do not place the COMPOSER PRO on high temperature devices such as power amplifiers
etc. to avoid overheating.
7.2 Audio connections
The audio inputs and outputs on the BEHRINGER COMPOSER PRO are fully balanced. If possible, connect
the unit to other devices in a balanced configuration to allow for maximum interference immunity.
Critical applications may require to build up a transformer-balanced configuration for the output signals, so as
to avoid interference from ground loops or potential differences. For this purpose, we offer our high-quality
output transformer OT-1 as a retrofit kit.
26
7. INSTALLATION
COMPOSER PRO MDX2200
Unbalanced use of
Balanced use of
mono 1/4" jack plugs
stereo 1/4" jack plugs
Tip =
Signal
Tip =
hot (+ve)
Ring =
cold (-ve)
Sleeve =
Ground / Shield
Sleeve =
Ground / Shield
Tip
Tip
Ring
Sleeve
Sleeve
Strain relief clamp
Strain relief clamp
For connection of balanced and
unbalanced plugs, ring and sleeve have
to be bridged at the stereo plug.
Balanced use with XLR connectors
2
1
1
2
1 = Ground / Shield
2 = hot (+ve)
3 = cold (-ve)
3
3
Input
Output
For unbalanced use pin 1 and pin 3 have to be bridged
Fig. 7.2: Different plug types
7.3 Selecting the operating level
With the OPERATING LEVEL switch on the rear of the BEHRINGER COMPOSER PRO you can adjust the
internal operating level of the unit. Thus, the COMPOSER PRO can be adapted perfectly to various levels (e.g.
both the typical home recording level of -10 dBV and the professional level of +4 dBu). The level meters are
referenced automatically to the selected level, i.e. an optimum operating range of the meters will always be
ensured.
7. INSTALLATION
27
COMPOSER PRO MDX2200
8. SPECIFICATIONS
AUDIO INPUT
Connectors
Type
XLR and 1/4" jack
RFfiltered, servo-balancedinput
50 kOhm balanced, 25 kOhm unbalanced
+4 dBu/-10 dBV switchable
+21 dBu balanced and unbalanced
typ. 40 dB, >55 dB @ 1 kHz
Impedance
Nominal operating level
Max. input level
CMRR
AUDIO OUTPUT
Connectors
Type
XLR and 1/4" jack
Electronically servo-balancedoutputstage(optionaltransformer-
balanced).
Impedance
Max. output level
60 Ohms balanced, 30 Ohm unbalanced
+21 dBu, +20 dBm balanced and unbalanced
SC INPUT
Connector
Type
1/4" jack
RF-rejecting, DCde-coupled, unbalancedinput
Impedance
Max. input level
>10 kOhm
+24 dBu
SC OUTPUT
Connector
Type
1/4" jack
RF-rejecting, DCde-coupled, unbalancedoutput
Impedance
Max. output level
2 kOhm
+21 dBu
SYSTEM SPECIFICATIONS
Bandwidth
Frequency response
Noise
20 Hz to 20 kHz, +0/-0.5 dB
0.35 Hz to 200 kHz, +0/-3 dB
>-95 dBu, unweighted, 22 Hz to 22 kHz
0.008 % typ. @ +4 dBu, 1 kHz, Gain 1
0.04 % typ. @ +20 dBu, 1 kHz, Gain 1
0.01 % typ. SMPTE
THD
IMD
Crosstalk
Stereo coupling
<-100 dB, 22 Hz to 22 kHz
True RMS detection
EXPANDER/GATESECTION
Type
Threshold
Ratio
IRC(InteractiveRatioControl)expander
variable (OFF to +15 dB)
variable (1:1 to 1:8)
Attack
Release
<1 ms / 50 dB, program dependent
variable (SLOW: 100 ms / 1 dB, FAST: 100 ms / 100 dB)
COMPRESSOR SECTION
Type
IKA(InteractiveKneeAdaptation) compressor
variable (-40 dB to +20 dB)
Threshold
Ratio
variable (1:1 to oo:1)
Threshold characteristics
Auto characteristics
Manual attack time
Manual release time
Auto attack time
Auto release time
Output
variable (Interactive or Hard Knee)
Wave adaptive compressor
variable (0.5 ms / 20 dB to 100 ms / 20 dB)
variable (0.05 ms / 20 dB to 5 s / 20 dB)
typ. 15 ms at 10 dB, 5 ms at 20 dB, 3 ms at 30 dB
program dependent, typ. 125 dB/s
variable (-20 to +20 dB)
28
8. SPECIFICATIONS
COMPOSER PRO MDX2200
PEAK LIMITER SECTION
Type
IGC(InteractiveGainControl)peaklimiter
Threshold
variable (+4 dB to OFF (+22 dBu))
Ratio
oo:1
Stage 1 Limiter Type
Attack
Clipper
“zero”
Release
“zero”
Stage 2 Limiter Type
Attack
Release
Program limiter
program dependent, typ. < 5 ms
program dependent, typ. 20 dB/s
FUNCTION SWITCHES
SC EXTERN
SC MON
Switches the detector section to the external SC input.
Monitoring the external SC input, disengaging the normal audio.
Enables the “Interactive KneeAdaptation” characteristics.
Allows for frequency dependent detection.
INTERACTIVE
CONTOUR
AUTO
Enables the automatic and program dependent setting of the
Attack-/release times, disengaging the manual attack-/release
controls.
I/O METER
IN/OUT
Switches between input and output for the level meter.
Relay controlled hard-bypass.
OPERATING LEVEL
COUPLE
Changes the internal reference level from +4 dBu to -10 dBV.
Linking both channels for stereo operation. Channel 1 becomes
master.
INDICATORS
GAIN REDUCTION
INPUT/OUTPUT LEVEL
Expander/gate threshold
Compressor threshold
Peak limiter threshold
Function switch
12 element LED display: 1/2/4/6/9/12/15/18/21/24/27/30 dB
12 element LED display: -30/-24/-18/-12/-6/0/+3/+6/+9/+12/+18 dB
2 LED for under “+” and above “-”
3 LEDs for under “+”, interactive “0“ and above “+”
1 LED for Indication of limiter function
LED indicator for each
OPTIONS
Output transformer
BEHRINGER transformer OT-1 refittable
POWER SUPPLY
Mains voltages
USA/Canada
U.K./Australia
Europe
120 V ~, 60 Hz
240 V ~, 50 Hz
230 V ~, 50 Hz
General export model
100 - 120 V ~, 200 - 240 V ~, 50 - 60 Hz
Fuse
100 - 120 V ~: T 250 mA H
200 - 240 V ~: T 125 mA H
max. 20 watts
Power consumption
Mains connection
standard IEC receptacle
PHYSICAL
Dimension
approx. 1 3/4" (44.5 mm) * 19" (482.6 mm) * 8 1/2" (217 mm)
Net weight
Shipping weight
approx. 2.2 kg
approx. 3.4 kg
BEHRINGER is constantly striving to maintain the highest professional standards. As a result of these efforts, modifications may be
made from time to time to existing products without prior notice. Specifications and appearance may differ from those listed or
shown.
8. SPECIFICATIONS
29
COMPOSER PRO MDX2200
9. WARRANTY
§ 1 WARRANTY CARD/ONLINE REGISTRATION
To be protected by the extended warranty, the buyer must com-
plete and return the enclosed warranty card within 14 days of
the date of purchase to BEHRINGER Spezielle Studiotechnik
GmbH, in accordance with the conditions stipulated in § 3. Fail-
ure to return the card in due time (date as per postmark) will void
any extended warranty claims.
3. Free inspections and maintenance/repair work are expressly
excluded from this warranty, in particular, if caused by improper
handling of the product by the user.
This also applies to defects caused by normal wear and tear, in
particular, of faders, potentiometers, keys/buttons and similar
parts.
Based on the conditions herein, the buyer may also choose to
use the online registration option via the Internet
4. Damages/defects caused by the following conditions are not
covered by this warranty:
s
s
s
misuse, neglect or failure to operate the unit in compliance
with the instructions given in BEHRINGER user or service
manuals.
§ 2 WARRANTY
1. BEHRINGER (BEHRINGER Spezielle Studiotechnik GmbH in-
cluding all BEHRINGER subsidiaries listed on the enclosed page,
except BEHRINGER Japan) warrants the mechanical and elec-
tronic components of this product to be free of defects in mate-
rial and workmanship for a period of one (1) year from the
original date of purchase, in accordance with the warranty regu-
lations described below. If the product shows any defects within
the specified warranty period that are not due to normal wear
and tear and/or improper handling by the user, BEHRINGER shall,
at its sole discretion, either repair or replace the product.
connection or operation of the unit in any way that does not
comply with the technical or safety regulations applicable in
the country where the product is used.
damages/defects caused by force majeure or any other
condition that is beyond the control of BEHRINGER.
5. Any repair or opening of the unit carried out by unauthorized
personnel (user included) will void the warranty.
6. If an inspection of the product by BEHRINGER shows that the
defect in question is not covered by the warranty, the inspection
costs are payable by the customer.
2. If the warranty claim proves to be justified, the product will be
returned to the user freight prepaid.
3. Warranty claims other than those indicated above are ex-
pressly excluded.
7. Products which do not meet the terms of this warranty will be
repaired exclusively at the buyer’s expense. BEHRINGER will
inform the buyer of any such circumstance. If the buyer fails to
submit a written repair order within 6 weeks after notification,
BEHRINGER will return the unit C.O.D. with a separate invoice
for freight and packing. Such costs will also be invoiced sepa-
rately when the buyer has sent in a written repair order.
§ 3 RETURN AUTHORIZATION NUMBER
1. To obtain warranty service, the buyer (or his authorized dealer)
must call BEHRINGER (see enclosed list) during normal business
hours BEFORE returning the product. All inquiries must be ac-
companied by a description of the problem. BEHRINGER will then
issue a return authorization number.
§ 5 WARRANTY TRANSFERABILITY
2. Subsequently, the product must be returned in its original
shipping carton, together with the return authorization number to
the address indicated by BEHRINGER.
This warranty is extended exclusively to the original buyer (cus-
tomer of retail dealer) and is not transferable to anyone who
may subsequently purchase this product. No other person (re-
tail dealer, etc.) shall be entitled to give any warranty promise on
behalf of BEHRINGER.
3. Shipments without freight prepaid will not be accepted.
§ 4 WARRANTY REGULATIONS
§ 6 CLAIM FOR DAMAGES
1. Warranty services will be furnished only if the product is
accompanied by a copy of the original retail dealer’s invoice.
Any product deemed eligible for repair or replacement by
BEHRINGER under the terms of this warranty will be repaired or
replaced within 30 days of receipt of the product at BEHRINGER.
Failure of BEHRINGER to provide proper warranty service shall
not entitle the buyer to claim (consequential) damages. In no
event shall the liability of BEHRINGER exceed the invoiced value
of the product.
§ 7 OTHER WARRANTY RIGHTS AND NATIONAL LAW
2. If the product needs to be modified or adapted in order to
comply with applicable technical or safety standards on a na-
tional or local level, in any country which is not the country for
which the product was originally developed and manufactured,
this modification/adaptation shall not be considered a defect in
materials or workmanship. The warranty does not cover any
such modification/adaptation, irrespective of whether it was
carried out properly or not. Under the terms of this warranty,
BEHRINGER shall not be held responsible for any cost resulting
from such a modification/adaptation.
1. This warranty does not exclude or limit the buyer’s statutory
rights provided by national law, in particular, any such rights
against the seller that arise from a legally effective purchase
contract.
2. The warranty regulations mentioned herein are applicable
unless they constitute an infringement of national warranty law.
The information contained in this manual is subject to change without notice. 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 BEHRINGER Spezielle Studiotechnik GmbH.
BEHRINGER and COMPOSER are registered trademarks.ALLRIGHTS RESERVED.
© 2001 BEHRINGER Spezielle Studiotechnik GmbH.
BEHRINGER Spezielle Studiotechnik GmbH, Hanns-Martin-Schleyer-Str. 36-38, 47877 Willich-Münchheide II, Germany
Tel. +49 (0) 21 54 / 92 06-0, Fax +49 (0) 21 54 / 92 06-30
30
9. WARRANTY
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