Compressor

Compressor

Smooths out the dynamic range of an audio signal — loud parts are reduced so quiet parts don't get drowned out. Built on FFmpeg's compander filter, with the standard broadcast controls (input gain, threshold, ratio, attack/release, knee, makeup, mix) plus advanced detector mode, channel link, and detection type. Includes a clip indicator and a one-click reset. The dedicated Compressor V2 offers richer real-time metering and look-ahead.

Compressor - Settings

Input

Input — overall level applied before the compressor.

Input
Property Description
Input gain (dB) Pre-compression gain, in decibels. [min=-24, max=24, default=0]. 0 leaves the signal unchanged. Negative values reduce the input level; positive values boost it before the compressor processes it.

Compression

Compression — the main controls that shape how the compressor reacts.

Compression
Property Description
Threshold (dB) Level above which the compressor starts working, in decibels relative to full scale. [min=-48, max=0, default=-9]. Audio louder than this gets reduced by Ratio; audio quieter than this is left unchanged. Lower (more negative) values catch more of the signal.
Ratio (1:1 - 20:1) How strongly audio above the threshold is reduced. [min=1, max=20, default=4]. Expressed as N:1. 1:1 is no compression; 4:1 is a typical broadcast setting; 10:1 or higher behaves like a limiter.
Attack (ms) How quickly the compressor reacts when the signal exceeds the threshold, in milliseconds. [min=1, max=200, default=5]. Short values catch fast transients but can sound "squashed". Longer values let initial peaks through before gain reduction kicks in.
Release (ms) How quickly the compressor stops working after the signal drops below the threshold, in milliseconds. [min=5, max=5000, default=200]. Short values let the compressor recover quickly; long values keep the gain reduction smooth across phrases.
Knee (1 - 8) Soft-knee width around the threshold. [min=1, max=8, default=2.8]. Controls how gradually the compressor engages near the threshold. Low values give a hard, punchy onset; high values give a soft, gentle engagement.

Output

Output — wet/dry mix and makeup gain.

Output
Property Description
Mix (%) Wet/dry mix between the compressed and original signals, as a percentage. [min=0, max=100, default=100]. 100 outputs only the compressed signal; 0 outputs only the original; values in between blend the two — known as parallel compression, useful for keeping the dynamics of the original while still tightening peaks.
Makeup gain (dB) Extra gain applied after compression to compensate for the level reduction. [min=0, max=24, default=0]. Compression always lowers the overall level; makeup gain brings the perceived loudness back up.

Advanced

Advanced — detector mode, channel link, and detection type.

Advanced
Property Description
Compressor mode CompressorMode — whether the compressor reduces volume above the threshold (Downward) or raises volume below the threshold (Upward). Downward is the standard mode — loud parts above the threshold get pulled down. Upward does the opposite, lifting quieter parts below the threshold up so soft details stand out.
Link How left and right channels are linked when the compressor decides how much to reduce. Pick a linking mode based on whether the channels should be processed together (preserving stereo image but reacting to the loudest of the two) or independently.
Detection How the compressor measures the input level — peak vs. RMS. Peak detection reacts to instantaneous peaks (more aggressive on transients). RMS reacts to the smoothed loudness (more transparent on voices and music).

Warnings

Warnings — clip indicators that flag when the signal is too loud.

Warnings
Property Description
Signal overload True when the compressor's output signal has clipped (read-only). Lights up when the combined effect of compression and MakeupGainDb pushes the signal above full scale. Auto-resets after 2 seconds.
Peak Overload (dB) Highest level reached during the most recent overload, in decibels (read-only). Updated whenever SignalOverLoad trips, and auto-resets after 2 seconds.

Actions

Actions — one-click commands.

Actions
Property Description
Reset Reset all settings to their broadcast-style defaults.

Inherits from: AbstractAudioOperator, AbstractOperator, AbstractAudioMetering.

See also: Compressor in Script Engine Objects.