Behringer MDX1600 - Manual (Page 7)

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AUTOCOM PRO-XL MDX1600/COMPOSER PRO-XL MDX2600/MULTICOM PRO-XL MDX4600
Application hints
Setting the compressor will be much easier if you first set both
limiter and expander to a neutral setting by turning both threshold
controls (TRIGGER and LIMITER) to OFF.
Setting the compression ratio requires your “sense of hearing”:
Anything goes. In general, however, the ratio setting should not
be too high for mix signals; instead, use 2:1 as a starting point to
preserve the natural sound of the music; a ratio setting of about
4:1 has proved successful for vocal recordings. The IKA
(Interactive Knee Adaptation) characteristic allows you to achieve
a gradual and inaudible compression and hence to use higher
ratios. If you want to use the compressor as an effect in its own
right, don‘t hesitate to experiment with higher values.
Turn the THRESHOLD control counter-clockwise until the GAIN
REDUCTION display reads the desired gain reduction (don’t
exceed 6 - 8 dB for mix signals). During this process the volume is
reduced audibly. Now turn the OUTPUT control clockwise until
this volume difference has been made up for. The levels of the
compressed vs. uncompressed signals can be compared with the
INPUT/OUTPUT LEVEL display activated with the I/O METER
switch. These two levels should be the same.
The AUTO function for the attack and release times provides a
program-dependent—and largely inaudible—dynamics control,
which suits most standard applications. If a somewhat more
“open” sound processing profile is required, you can set the
attack and release times manually (AUTO switch not pressed).
Start with a longer Release time, then make it gradually shorter.
You will soon notice an unnatural pumping effect caused by rapidly
changing levels. Select a longer release time until the effect cannot
be heard any longer.
The Attack time setting, too, is highly dependent on the music
material. Select longer attack times for a subtle and musical
compression. As a result you avoid attack portions of treble signals
being cut off if compression is triggered by a high-level bass drum
beat that is played at the same time. The sound remains
transparent and compact throughout.
If the compressor is being used as a limiter, the attack time
should be as short as possible. This, in combination with a high
ratio (>20:1), a medium to long release time and the maximum
possible threshold will protect your sound reinforcement system
effectively from getting overloaded.
2.3 The dynamic enhancer section
Fig. 2.4: Dynamic enhancer section control elements
The dynamic enhancer circuit implemented in all three dynamic
processors allows you to dynamically enhance the treble range.
Since the bass portions of a music signal often have the highest
energy yield, they usually are the ones that trigger the compression
process, thus also reducing the gain of middle to high frequencies.
The enhancer controls the compression process and gradually
adds more highs, the stronger the treble range is compressed, so
as to make up for the subjective loss of high-frequency content.
LEVEL control (MDX1600). The AUTOCOM PRO-XL
features an adjustable enhancer, on which you can set
the amount of treble boost with the LEVEL control.
ENHANCER switch (MDX2600 and MDX4600). Activates
the dynamic enhancer.
ENHANCER LEVEL. The LED chain reads the current treble
boost within a range from -30 to 0 dB (MDX1600 only).
IN/OUT switch (MDX1600). Use this switch to activate the
enhancer circuit, e.g. to assess the effect the enhancer has
on the audio signal.
2.4 The de-esser section
Fig. 2.5: De-esser section control elements
From a circuitry point of view, the de-esser is placed in the side-
chain path of the compressor, so it will operate only if the
compressor is active.
LEVEL control (MDX2600). Instead of an adjustable
enhancer, the COMPOSER PRO-XL has a controllable de-
esser, which helps you eliminate hiss noise contained in
the audio signal. The LEVEL control determines the amount
of frequency suppression.
DE-ESSER switch (MDX1600). The AUTOCOM PRO-XL
also has a de-esser. At the touch of a button you can enhance
the audio signal considerably, especially when processing
vocal recordings. Switch can be found in the compressor
section.
DE-ESSER LEVEL (MDX2600). The LED chain reads the
current attenuation within a range from +3 to +12 dB.
MALE switch. This switch adapts the de-esser to the male
(switch pressed) or female registers (not pressed).
IN/OUT switch. Switches the de-esser on and off.
2.5 The peak limiter section
Fig. 2.6: Peak limiter section control elements
The peak limiter limits the signal to an adjustable level. When
the LIMITER control is turned fully to the right, the limiter
is switched off. Owing to its extremely fast “zero” attack,
this circuit is capable of limiting signal peaks without any
overshoot. If the signal is limited for more than 20 ms, the
overall gain is reduced for about 1 s to avoid strong and
thus audible limiter effects.
2. CONTROL ELEMENTS AND CONNECTORS