12
INTELLIGATE XR2000
2.2.3 RANGE control
The control of the dynamics process in the INTELLIGATE is provided by a high performance VCA. Its effective
range is more than 100 dB, which means that the input signal can be attenuated up to 100 dB.
In most applications, it is not desirable for the signal to be gated off completely when the signal drops below the
threshold. This usually introduces chopping within the sound, especially when there is a significant amount of
background noise to be suppressed, which does not lead to an advantage. The unit includes a RANGE control,
which adjusts the maximum amount of attenuation. Using this control, it is possible to attenuate the signal
slightly, so that the overall naturalness can be maintained, especially when handling very noisy signals.
2.2.4 IRC (Interactive Ratio Control)-EXPANDER
The response characteristics 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. In an application which requires “inaudible”
expansion, it is advantageous to create a gentle “Soft Knee” characteristic during a contiguous transition
through the threshold.
A newly developed IRC (Interactive Radio Control) Expander has been integrated into the INTELLIGATE. The
ratio curve characteristic automatically adapts itself, dependent on programme material.
At lower ratios with reducing expansion, the transition is “gentle”, whereas higher ratios and increasing expansion
will result in “harder” transitions within the curve.
The ICR Expander is therefore equipped with a soft, interactive non-linear ratio curve, which is best suited to the
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.
Fig. 2.3: IRC curve characteristic of the Expander
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.
2.3
RATIO control
The change of output relative to the change of input, when the key signal is below threshold, is called the
expansion ratio, and is adjustable with the RATIO control. This control adjusts an important parameter, it
changes the function of the section from an expander to a gate.
Low ratios, from 1.2:1 about 3:1 produce precisely controlled downward expansion, with more pronounced
effects as the ratio increases to 30:1, where the unit functions as a gate.
The scale of the ratio is calibrated in dB on the front panel. It indicates the decrease in output level, resulting
from a 1 dB decrease in input level.
2. OPERATION
