Linux Studio Plugins Project

# Sidechain Compressor Stereo

Detailed: LSP Sidechain Compressor Stereo (SCK1S)

Formats: CLAP, GST, LADSPA, LV2, VST2, VST3

Categories: Compressor

Developer: Vladimir Sadovnikov

Description:

This plugin performs compression of stereo input signal. Flexible sidechain-control configuration and additional sidechain inputs are provided. Different types of compression are possible: downward, upward and parallel. Also compressor may work as limiter in Peak mode with high Ratio and low Attack time.

The compressor can provide two release times. If the compressor's envelope indicated by the dot on the compression curve is above the ‘Release Thresh’ then the ‘Release Time’ parameter is taken as a release time for processing. Otherwise, if the envelope is below the ‘Release Thresh’ then the ‘Attack Time’ parameter is taken as a release time for processing.

Additionally, Stereo split mode allows to apply processing to the left and right channels independently while keeping the same settings for the left and right channels.

Controls:

- Bypass - bypass switch, when turned on (led indicator is shining), the plugin bypasses signal.
- Pause - pauses any updates of the compressor graph.
- Clear - clears all graphs.
- Stereo Split - enables independent compression of left and right channels.
- Gain L, R - enables drawing of gain amplification line and corresponding amplification meter.
- SC L, R - enables drawing of sidechain input graph and corresponding level meter.
- Env L, R - enables drawing of compressor's envelope graph and corresponding level meter.
- In L, R - enables drawing of compressor's input signal graph and corresponding level meter.
- Out L, R - enables drawing of compressor's output signal graph and corresponding level meter.
- Link - the name of the shared memory link to pass sidechain signal.
- Pre-mix - shows pre-mix control overlay.
- Sidechain - shows the sidechain control overlay.
- Mix - shows the Dry/Wet control overlay.

'Compressor' section:

- Mode - compression mode

- Downward (Down) - the downward compressor.
- Upward (Up) - the upward compressor.
- Boosting (Boost) - the boosting compressor (upward with precise boost control).

- Ratio - compression ratio.
- Knee - size of compression knee.
- Makeup - additional amplification gain after compression stage.
- Boost - this knob is related to upward and boosting compression modes only. For upward mode it defines the threshold below which the constant amplification will be applied to the input signal. This prevents compressor from applying infinite amplification to very quiet signals. For boosting mode it defines the overall boost of the signal. The boost threshold is computed automatically.
- Attack Thresh - threshold of the compressor, placed in the middle of the knee.
- Attack Time - attack time of the compressor.
- Release Thresh - relative to the Attack Thresh threshold that sets up the threshold of Release Time. If the current compressor's envelope value is below the configured Release Threshold, the release time is being considered to be the same to the attack time.
- Release Time - release time of the compressor.
- Hold - the time period the envelope holds it's maximum value before starting the release.

'Signal' section:

- Input - overall input gain.
- Output - overall output gain.

Pre-mix control overlay:

- In -> SC - the amount of signal from input channel added to the Sidechain.
- In -> Link - the amount of signal from input channel added to the shared memory link.
- SC -> In - the amount of signal from sidechain input channel added to the input channel.
- SC -> Link - the amount of signal from sidechain input channel added to the shared memory link.
- Link -> In - the amount of signal from shared memory link added to the input channel.
- Link -> SC - the amount of signal from shared memory link added to the sidechain channel.

Sidechain control overlay:

- Position - the position of the sidechain input. Available variants:

- Feed-forward - sidechain input is connected to compressor's input. More aggressive compression.
- Feed-back - sidechain input is connected to compressor's output. Vintage-style more accurate compression.
- External - sidechain signal is taken from additional (external) sidechain inputs of plugin.
- Link - sidechain input is passed by shared memory link.

- Listen - allows to listen the processed sidechain signal.
- Preamp - pre-amplification of the sidechain signal.
- Reactivity - reactivity of the sidechain signal.
- Lookahead - look-ahead time of the sidechain relative to the input signal.
- Type - combo box that allows to switch different types for sidechain processing. Available types are:

- Peak - peak mode.
- RMS - Root Mean Square (RMS) of the input signal.
- LPF - input signal processed by recursive 1-pole Low-Pass Filter (LPF).
- SMA - input signal processed by Simple Moving Average (SMA) filter.
- Middle - middle part of signal is used for sidechain processing.
- Side - side part of signal is used for sidechain processing.
- Left - only left channel is used for sidechain processing.
- Right - only right channel is used for sidechain processing.
- Min - the absolute minimum value is taken from stereo input.
- Max - the absolute maximum value is taken from stereo input.
- Left/Right - left and right channels are being processed using respectively the left and right sidechain channels in stereo split mode.
- Right/Left - left and right channels are being processed using respectively the right and left sidechain channels in stereo split mode.
- Mid/Side - left and right channels are being processed using respectively the middle and side parts of sidechain signal in stereo split mode.
- Side/Mid - left and right channels are being processed using respectively the side and middle parts of sidechain signal in stereo split mode.

- LPF - allows to set up slope and cut-off frequency for the low-pass filter applied to sidechain signal.
- HPF - allows to set up slope and cut-off frequency for the high-pass filter applied to sidechain signal.

Dry/Wet mix control overlay:

- Mix Dry - the amount of dry (unprocessed) signal, useful for parallel compression.
- Mix Wet - the amount of wet (processed) signal, useful for parallel compression.
- Mix Dry/Wet - the knob that controls this balance between mixed dry and wet signal (see Mix Dry and Mix Wet) and the dry (unprocessed) signal.