How to compress the master bus

On the master bus, gentle and slow: threshold around −2dB below your loudest peaks, ratio 2:1, attack 30ms, release auto.

Updated 2026-05-03

Short answer

On the master bus, gentle and slow: threshold around −2dB below your loudest peaks, ratio 2:1, attack 30ms, release auto. Aim for 1–2dB of gain reduction on the peaks. More than 3dB and you're using the master compressor to fix mix problems instead of polish them.

Threshold: aim for 1–2 dB of gain reduction on peaks
Ratio: 2:1, gentle glue
Attack: 30 ms, preserves transients across the mix
Release: auto, follows song tempo
Knee: 6 dB, smooth onset

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Aim for 1–2dB gain reduction

Master bus compression is glue, not loudness. Pull the threshold down until the meter shows 1–2dB on the loudest sections. More than 3dB and you're squashing the mix; less than 0.5dB and you might as well not have the compressor inserted. Loudness comes from the limiter, not the compressor.

Ratio 2:1 keeps it transparent

2:1 is the standard mastering ratio, gentle enough to preserve dynamics, audible enough to glue. 4:1 starts to sound like compression. Above 4:1 and the master loses the punch and depth that make it sound finished.

Slow attack (30ms) preserves transients

A fast attack (1–5ms) clamps every kick and snare across the entire mix and the song goes flat. 30ms lets transients through before the compressor engages. If your mix is already dynamic and punchy, push to 50ms. Don't go faster than 10ms on the master.

Auto release follows the song

Auto release lets the compressor adapt to the tempo, fast for fast songs, slow for slow songs. If your compressor doesn't have auto, start at 100ms. Too fast and you'll hear pumping on every kick; too slow and the compressor never recovers between sections.

Frequently asked

Should I compress the master bus?

Optional. Many engineers print master compression (1–2dB GR with a glue compressor) during mixing for cohesion. Mastering then adds further dynamics processing. If you don't have a clear reason for it, skip it and let the limiter handle dynamics control.

How much gain reduction on the master bus?

1–2dB is the polish range. 2–3dB is the glue range. More than 3dB and you're using the master compressor to fix mix problems, go fix the mix instead. Loudness comes from the limiter, not the compressor.

What is the best master bus compressor?

SSL bus compressor and clones are the universal mastering glue choice (4:1, 30ms, auto release). For more transparent results, use a clean digital VCA design. The plugin matters less than the settings, gentle ratio, slow attack, auto release.

Should master compression go before or after EQ?

Both are valid. EQ before compression lets you shape what the compressor reacts to. EQ after compression lets you correct any tonal shifts the compression introduces. A common chain: corrective EQ → bus compressor → tonal EQ → saturation → limiter.

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