Nilfisk-ALTO ACL2 Pro - Manual (Page 11)

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27. Sidechain Send
Through this 1/4" unbalanced jack the audio signal can be routed to an external processor.
28. Sidechain Return
The return signal of an external processor will be processed through this 1/4" jack.
4. READY TO ROLL?
4.1 Expander/Gate Section
Chart. 3 Function of an expander
Chart. 4 SRC Curve characteristics of the Adaptive Expander
4.1.1 Threshold djustment A
The threshold control covers a very wide range and it is efficient with any working level. Turn the threshold
control fully counterclockwise and the Expander/Gate section will be completely off.
4.2 Compressor Section
4.2.1 Another Threshold Control?
The compressor threshold control sets the point where the input level starts to be reduced. Let's say the
level is +12dBu and the threshold control is set at +2dBu: In this case up to 10 dB can be compressed. If
the input level is the same and the control is set at -10dBu the maximum compression will be 22dB. The
operating range of the threshold control is -40 to +20dBu. Turn the threshold control fully clockwise and you
will get a threshold level of +20dBu.
You must remember that the degree and the type of compression not only depend on the threshold control
but also on other controls such as Ratio, Attack and Release.
SRC CURVE
As we told you previously in this Manual the downward expander will reduce automatically the level of the audio
signal when such signal is below a set threshold. So the expander is the opposite of the compressor/limiter. We
also explained to you how the ratio curve of the expander is flat while a noise gate it is more brutal processor: It
simply cut-off the entire signal below a certain set threshold. The ACL2 PRO is equipped with a new kind of expander,
the SRC (Smart Ratio Control). The ratio of the SRC is automatically adjusted according to the audio signal level.
In fact, conventional expanders could easily cut part of the musical program with unacceptable result: The gain
changes become audible. We have equipped the SRC with a non-linear ratio curve, which is soft and adjustable
by the User. Thanks to the SRC low passages close to noise floor level will be processed with a minimum ratio of
expansion while for signals of reduced level a higher ratio will be used with resultant greater attenuation.