3.5

90MainStage Effects
Compressor sidechain parameters
• Detection buttons: Choose the way stereo sidechain signals are handled at the
sidechain input.
• Max button: Turn on to compress both channels if either stereo channel exceeds or
falls below the threshold.
• Sum button: When enabled, the combined level of both channels must exceed the
threshold before compression occurs.
• Peak/RMS buttons: Use in conjunction with the Max and Sum buttons. Choose Peak
or RMS to determine whether signal peaks or a signal average is used for detection.
These can help with avoiding artifacts such as clicks in the processed signal,
depending on the type of audio material and parameter settings (notably Attack).
• Filter buttons: Turn the filter on or off. Turn on Listen to monitor the sidechain signal.
• Filter mode knob: Choose the type of filter used to process the incoming side chain
signal. Filtering the sidechain input signal can enhance the precision of trigger signals,
resulting in more surgical compression. The choices areLP (lowpass), BP (bandpass),
HP (highpass), ParEQ (parametric), and HS (high shelving).
• Frequency knob and field: Set the center frequency for the side chain filter.
• Qknob and field: Set the width of the frequency band affected by the side chain filter.
• Gain knob and field: Set the amount of gain applied to the side chain signal.
Use MainStage Compressor
This section explains how to effectively use the main Compressor parameters.
Tip: Click the Meter or Graph button to change the meter. This visual aid can help you
to achieve more precise compression.
Compressor Threshold and Ratio
The most important Compressor parameters are Threshold and Ratio. The Threshold
parameter sets the floor level in decibels. Signals that exceed this level are reduced by the
amount set as the Ratio.
The Ratio parameter is a percentage of the overall level; the more the signal exceeds the
threshold, the more it is reduced. A ratio of 4:1 means that increasing the input by 4dB
results in an increase of the output by 1dB, if above the threshold.
For example, with the Threshold set at −20dB and the Ratio set to 4:1, a −16dB peak in
the signal (4dB louder than the threshold) is reduced by 3dB, resulting in an output level
of −19dB.