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Dynamic Range Compression Visualizer

Set a compressor’s threshold, ratio, knee and makeup gain and watch the transfer curve (input level vs output level) redraw, with the gain reduction at any input you choose.

This visualizes the standard static compressor curve (a soft-knee transfer function). It illustrates the level mapping; it doesn’t model attack/release timing, look-ahead or program-dependent behavior, and it doesn’t process audio.

Compressor settings

Transfer curve

Dashed line = 1:1 (no compression). Green curve = output for each input. The dot marks your test input.

Reading the Curve

A compressor turns down audio that rises above a threshold. Below the threshold the transfer curve follows the 1:1 dashed line (output = input). Above it, the curve’s slope flattens to 1/ratio — at 4:1, every 4 dB of input above threshold produces just 1 dB more output. The knee rounds the transition: a hard knee (0 dB) bends sharply at the threshold, while a soft knee eases compression in over a range of levels. Makeup gain lifts the whole curve back up to recover the level lost to compression.

The gap between the 1:1 line and the curve at any input is the gain reduction there — how many dB the compressor is pulling down (before makeup). This static curve is the heart of a compressor; in a real one, attack and release control how quickly it moves along this curve as the signal changes.

Frequently Asked Questions

What does ratio mean?
It’s how hard the signal is compressed above the threshold. 4:1 means 4 dB of input over threshold becomes 1 dB of output over threshold. ∞:1 (very high) is limiting — output barely rises above the threshold.
Hard knee vs soft knee?
A hard knee (0 dB) applies the full ratio abruptly at the threshold. A soft knee blends from 1:1 to the full ratio over a range of dB around the threshold, for a smoother, more transparent sound.
What is makeup gain for?
Compression lowers peaks, so the overall level drops. Makeup gain raises everything back up so the compressed signal is as loud as before — it shifts the whole transfer curve upward.
What is gain reduction?
The number of dB the compressor is attenuating at a given input — the vertical distance between the 1:1 line and the curve before makeup. It grows as the input goes further above the threshold.
Does this model attack and release?
No. This shows the static transfer curve — the level mapping once the compressor has settled. Attack and release govern how fast it moves along that curve, which a static plot can’t show.
Does it process my audio?
No. It only draws the curve and computes levels from the numbers you enter. Apply the settings in your DAW or compressor plugin.