11.3

THE MCLASS EFFECTS676
About the Sidechain inputs
D When a signal is connected to the Sidechain inputs, it is this signal that will trigger the compression.
This signal is not passed to the compressor output, and will thus not be heard (unless Sidechain Solo is activated).
D The signal connected to the normal L/R inputs is the signal that will be processed by the compressor (as
usual).
Here follows two examples of how you can use sidechain processing:
Example 1 - using the Sidechain inputs to create ducking effects
“Ducking” is when the level of one signal is reduced by the presence of another signal. A typical application is to au-
tomatically lower the level of a musical bed when a voice-over starts, and to automatically bring the level up when the
voice-over stops. To set this up, we can name the musical bed in the example “Device A”, and the voice-over “Device
B”. Proceed as follows:
1. Connect Device A and Device B to separate channels on a mixer device.
In this example the signal produced by Device A should be continuous, and the signal produced by Device B
should be intermittent, i.e. it should contain both silent passages and signal passages.
2. Select Device A and then select an MClass compressor from the Create menu.
The effect will be auto-routed as an insert effect to Device A.
3. Connect a Send on the mixer device to the Sidechain inputs on the MClass compressor.
As soon as anything is connected to the Sidechain inputs, the “Active” indicator lights up on the device panel. The
compressor will no longer react to the signal produced by Device A.
4. Turn up the corresponding AUX Send level for Device B on the mixer.
This means that the Device B signal now feeds both the mixer's input, and the sidechain input on the compressor,
which in turn triggers the gain reduction.
5. If you now start playback of both devices, the level of Device A will be lowered whenever Device B sounds, and
be raised again when Device B stops.
The amount of gain reduction, how quickly it lowers the level, and the time it take for the level to return to normal
again is determined by the corresponding Gain/Threshold/Ratio and Attack/Release parameters.
Example 2 - using the Sidechain inputs to create frequency sensitive compression
By inserting an equalized signal to the sidechain inputs you can make the compression more or less sensitive to a
certain frequency range. A typical application of this is “de-essing” - where harsh “S”-sounds in vocal material is re-
duced or eliminated.
Frequency sensitive compression is set up as follows:
1. Hold down [Shift] and create an instrument device.
Pressing [Shift] means no auto-routing connections to/from the device are made.
2. Hold down [Shift] and create a MClass Equalizer.
3. Hold down [Shift] and create a MClass Compressor.
4. Create a Spider Audio Merger and Splitter device.
5. Connect the outputs of the instrument device to the A and B inputs on the Spider.