How Does It Work?#

Compressor FF-VCA is a stereo feed-forward VCA compressor with external sidechain support, selectable detector behavior, lookahead, and parallel compression controls.

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Quick Overview#

• Stereo program inputs: In L and In R.
• Optional stereo sidechain inputs: SC L and SC R.
• Detector can run in Peak or RMS mode.
• Mix enables parallel compression.
• The panel includes a live dynamics scope plus input, output, and gain-reduction meters.

Inputs And Outputs#

Port	Type	What It Does
In L	Audio input	Left program input.
In R	Audio input	Right program input.
SC L	Audio input	Left external sidechain input.
SC R	Audio input	Right external sidechain input.
Thr CV	CV input	Bipolar threshold modulation. ±5V maps to about ±24 dB.
Ratio CV	CV input	Bipolar ratio modulation around the panel setting.
Mix CV	CV input	Bipolar dry/wet modulation around the panel setting.
Makeup CV	CV input	Bipolar makeup gain modulation around the panel setting.
Out L	Audio output	Left compressed output.
Out R	Audio output	Right compressed output.

Controls Reference#

Control	Range / Values	Default	Behavior
Threshold	-60..0 dB	-18 dB	Compression threshold.
Ratio	1..20	4	Compression ratio.
Attack	0.1..100 ms	10 ms	Attack time for gain reduction.
Release	10..2000 ms	120 ms	Release time for gain reduction.
Knee	0..24 dB	6 dB	Soft-knee width.
Makeup	-12..24 dB	0 dB	Output makeup gain.
Mix	0..1	1	Dry/wet blend.
SC HPF	20..500 Hz	120 Hz	High-pass filter on the detector path.
Lookahead	0..10 ms	0 ms	Delays the program path so the detector can react earlier.
Detector	Peak, RMS	Peak	Chooses transient-focused or energy-focused detection.
Auto Rel	Off, On	Off	Adapts release timing to the amount of gain reduction.
Link	Off, On	On	Links left and right compression behavior for stereo material.
Auto MU	Off, On	Off	Applies automatic makeup gain.

Behavior Notes#

• If no sidechain cable is connected, the compressor detects from the program input.
• If only one sidechain side is patched, that external signal is reused across the detector so the compressor still has a complete stereo control path.
• Peak mode reacts faster to transients; RMS mode follows average energy over a short window.
• Mix blends dry and compressed signal inside the module, so it works as true parallel compression.
• The scope section visualizes detector level, envelope movement, and gain reduction in real time.