Compressor

The purpose of the Compressor is to control the dynamic range of the Output above a set Threshold Level.

The Compressor can be adjusted from unity (1:1) with the Input, to an almost flat (100:1 - very little amplitude variation) Output. Using the Depth control, you can control the point at which compression stops increasing, even though the Input level continues to increase.

The control settings for the Compressor Component affect all the Input Channels based on calculations made using the highest Input level. If you want to separately control the compression for multiple Channels, simply add more Compression Components.

Inputs and Outputs

Note: The number of signal pins is variable and set in the component's Type Property.

Input Pins

Channels

Audio signal pins are represented by a () circle, and traditional wiring is represented by a thin black line. You can use Signal Names on audio signal pins.

By default, the Compressor component is set to a Mono channel, which provides one input and one output. Additionally, you can set the Properties to allow for Stereo, which gives you two inputs and outputs; or you can choose Multi-Channel, which will allow you to choose between 2 and 256 inputs and outputs.

Output Pins

Channels

Audio signal pins are represented by a () circle, and traditional wiring is represented by a thin black line. You can use Signal Names on audio signal pins.

Properties

Tip: For additional properties not listed, refer to the Properties Panel help topic for more information.

Compressor Properties

Side Chain Input

Provides one Side Chain input per Channel. The Side Chain allows you to filter a signal before using it to control the dynamic range of the unfiltered Inputs.

In Gain is always applied to the Side Chain input signal, regardless of the state of Bypass.

Note: If you select Side Chain Input = Yes, and don't use the Side Chain Inputs, you will not have any compression control.

Detector Time

Sets one of three pre-set times, or enables the Detector Time control in the Control Panel. If one of the three pre-set times is chosen, the control is not available in the Control Panel.

Sets the time it takes for the Detector level to reach 63% of a change in the Input signal.

This adjustment is to prevent changes (spikes, low frequency signals) in the input from causing unwanted, momentary output.

Bypass Gain Meter

When set to Active, the Applied Gain meter is active regardless of the state of the Bypass button. This means you can adjust the Compressor in Bypass mode.

When set to Inactive, the Applied Gain meter is inactive to indicate that the component is in Bypass mode.

Channels

Type

Sets the type of Channel available for Inputs and Outputs.

Count

Only appears when choosing Multi-Channel as the Type. Sets the number of Channels for Multi-channel. You can choose between 2 and 256.

Controls

Response Panel and Detector

In Gain (dB)

The Input Gain adds to the level of the Input source.

Detector (dB)

Graphically and numerically displays the RMS level of the Input.

Response Panel

Graphically represents the Gain Calculations for the Channel having the highest Input RMS level.

X axis represents the Input

Y axis represents the Output

The red dot represents the Output Level. Below the Threshold Level the Output is equal to the Input, above the Threshold level it is adjusted by the Compressor.

Bypass

Bypasses the Compressor functionality.

Applied Gain (dB)

Graphically and numerically displays the amount of Gain applied to the Channel with the highest RMS Input level. The same amount of Gain, calculated based on the highest Channel, is applied to all other channels that are above the Threshold Level regardless of their relation to the Target Level.

Graphically the meter starts from the top, displaying attenuation in red going down.

Out Gain (dB)

Controls the output level.

Gain Calculation

Threshold Level (dBFS)

Sets the level where compression begins. This is the point from which the amount of attenuation is calculated based on the Ratio setting.

Assuming only one Input, a level below the Threshold Level is not compressed, anything above the Threshold Level attenuation is applied.

Example

If the:

Threshold Level is -15 dB
Ratio is 2.5
Input level is 10 dB

Then the Adjusted Output is:

(((Input Level - Threshold Level) / Ratio) + Threshold Level) = Output Level

((10 dB - (-15 dB) / 2.5) + (-15 dB)) = -5 dB

Ratio ( n:1)

The ratio between the Input and the Output as measured from the Threshold Level.

The closer the Ratio is to 100, the smaller dynamic changes in the Output level. As the Ratio is adjusted closer to 1, the dynamic range of the Output increases.

Depth (dB)

Sets the maximum amount of attenuation applied to the Input.

As the Input increases, the Compressor applies more attenuation based on the Ratio setting. When the amount of attenuation applied reaches the Depth setting, no more attenuation is added.

Soft Knee (dB)

Provides a smooth transition, in the Output, from the uncompressed level to the compressed level.

The Soft Knee slowly adds attenuation, as the Input increases, until the attenuation added by the Soft Knee is equal to the attenuation added by the Ratio setting.

Time Constants and Gain Meter

Attack Time (seconds)

Sets the time it takes for the Input to drop to 63% of the Depth level.

A long Attack Time causes the Output to stay closer to unity with the Input as the Input increases, then slowly drop to the desired Output level. A fast Attack Time causes the Output to get to the desired level faster without getting as close to unity with the Input.

Release Time (seconds)

Sets the time it takes for the Output to reach 63% of the Threshold Level.

This prevents the Output from dropping to quickly when the Input drops. Provides a smoother transition from a high Output to a lower Output.

Detector Time (seconds)

Available only when Detector Time Property is set to Use Control.

Sets the time it takes for the Detector level to reach 63% of a change in the Input signal.

This adjustment is to prevent changes (spikes, low frequency signals) in the input from causing unwanted, momentary output.

Control Pins

The available Control Pins depend on settings in Properties.

Pin Name	Value	String	Position	Pins Available
Applied Gain	-20 to 20	-20 dB to 20 dB	0.000 to 1.00	Output
Attack Time	0.0001 to 100	.100 ms to 100 ms	0.000 to 1.00	Input / Output
Bypass	0 1	active bypass	0 1	Input / Output
Depth	0 to 60	0 dB to 60 dB	0.000 1.000	Input / Output
Detector Level	-100 to 20	-100 dB to 20 dB	0.000 to 1.00	Output
Detector Time	0.0001 to 100	.100 ms to 100 ms	0.000 to 1.00	Input / Output
Input Gain	-20.0 to 20.0	-20.0 dB to 20.0 dB	0.000 to 1.00	Input / Output
Output Gain	-20.0 to 20.0	-20.0 dB to 20.0 dB	0.000 to 1.00	Input / Output
Ratio	1.00 to 100	1.00 to 100	0.000 to 1.00	Input / Output
Release Time	0.010 to 10	10.0 ms to 10 s	0.000 to 1.00	Input / Output
Soft Knee	0 to 24.0	0 dB to 24 dB	0.000 to 1.00	Input / Output
Threshold Level	-60 to 20	-60 dB to 20 dB	0.000 to 1.00	Input / Output