Behringer SNR2000 - Manual (Page 13)

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DENOISER SNR2000
Fig. 2.3: The function of an expander
2.4 The IRC expander of the DENOISER
The response characteristics of conventional expanders tend to cut the signal abruptly and the result is
generally unacceptable, since the effect is clearly audible. “Inaudible” expansion, however, requires a gentle
“Soft Knee” characteristic due to a continuous transition of the straight lines at the threshold.
A newly developed IRC (Interactive Ratio Control) expander has been integrated into the DENOISER. The ratio
curve characteristic automatically adapts itself, dependent on the program material.
With low ratios and a slight expansion, the transition is “gentle”, whereas higher ratios and increasing
expansion will result in “harder” transitions within the curve.
The IRC expander is therefore equipped with a soft, interactive non-linear ratio curve which is best suited to
the human hearing. Critical signals around the threshold level are processed with low expansion ratio
settings, whereas low signals will be subjected to an increasingly higher ratio which will result in greater
attenuation.
Fig. 2.4: IRC curve characteristic of the expander
The result is an expander which can be adjusted without the risk of alienating the overall sound. Furthermore,
the expander is more tolerant towards those usable signals which appear slightly above the noise floor.
2. OPERATION