Introduction – Behringer MDX1400 User Manual

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AUTOCOM PRO MDX1400

1. INTRODUCTION

In purchasing the new AUTOCOM PRO Model MDX1400, you have acquired an extremely efficient and

universal dynamics processor, which combines the most commonly used dynamic functions within a compact

stereo unit: every channel has its own independent Compressor/Limiter, an Expander/Gate and a Dynamic

Enhancer. The precision and flexibility of the functions are the main outstanding features of this high end unit.
Advanced BEHRINGER Technology
Compared to its predecessors, the AUTOCOM PRO offers several advanced features such as the extended

LED meters, balanced inputs and outputs, a couple function for the two channels and the sidechain filter.

Additionally, we have succeeded in refining the audio properties as well as the circuit topology.
For the first time, the AUTOCOM PRO MDX1400 uses SMD technology (Surface Mounted Device). These

sub-miniature components known from aerospace technology allow for an extreme packing density, plus

improve the units reliability. Additionally, the unit is manufactured under ISO9000 certified management

system.

1.1 The Design Concept

The philosophy behind BEHRINGER products guarantees a no-compromise circuit design and employs the

best choice of components. The operational amplifiers NJM4580 which are used in the AUTOCOM PRO, are

exceptional. They boast extreme linearity and very low distortion characteristics. The most important aspect

of the AUTOCOM PRO design is a radical VCA implementation which results in outstanding technical

specification and excellent performance. To complement this design the choice of components includes high

precision resistors and capacitors, detent potentiometers and several other stringently selected elements.
Despite the extremely complex internal circuitry, the unit has a control surface which is clearly laid out and

easy to understand. The internal design of the unit, together with its external sidechain path, gives the user all

the creative flexibility when processing sound.

IKA (Interactive Knee Adaptation) Compressor
Our proven IKA (Interactive Knee Adaptation) circuit successfully combines the concept of a hard knee

compressor with the characteristics of a soft knee approach. This program-dependent regulation scheme

forms the prerequisite both for inaudible and musical program compression and for creative and highly

effective dynamics processing.
The chosen value for the compression-ratio is being reached after the signals level is higher then 10 dB above

the treshold point. This stands for an extremely smooth impact of the compression. Thereby a convincingly

dense audiomaterial can be achieved: Even at extreme levels of compression or while processing critical

audiodata (e. g. classical music), your material stays musical, transparent and free from breathing or pump-

like effects in a wide range. With its IKA circuit the AUTOCOM PRO is capable of delivering outstanding

musical results both in studio and live PA applications.
Additionally, the AUTOCOM PROs sidechain filter allows for limiting the influence low-frequency signal

portions usually have on the control logic, so that the compression ratio is mainly determined by those

frequencies that are essential to the loudness perceived by the listener the midrange frequencies.

IRC (Interactive Ratio Control) Expander
A basic problem in the use of a compressor is the fact that the noise floor is highly amplified during quiet

sections or when there are music pauses. This effect is exaggerated when the compression ratio is

inappropriate. In order to eliminate this problem, one would normally use an additional expander or gate. The

noise is then simply faded out in the quiet sections. However, simple expanders, even when they are used

correctly, drastically cut signals below the preset threshold. This effect becomes more noticeable during the

transition from signal to noise floor. This can mean, that the start or end of words can be cut on a vocal track.
A newly developed IRC (Interactive Ratio Control) Expander has been integrated into the AUTOCOM PRO the

ratio of which, is automatically adjusted, depending on the program material. The result is an expander which

is less critical of adjustment and which is more tolerant in the presence of those signals which appear slightly

above the noise floor. Because of its new IRC circuit design, the BEHRINGER AUTOCOM PROs Expander/

1. INTRODUCTION