Ratio (Compressor)
Definition
The amount of gain reduction applied by a compressor relative to how far a signal exceeds the threshold. A 4:1 ratio means that for every 4 dB above the threshold, only 1 dB passes through.
In Simple Terms
How much a compressor squeezes the sound that goes above the threshold. A 2:1 ratio is gentle—barely noticeable. An 8:1 ratio is aggressive—really clamping down. Higher ratios mean more obvious compression.
In Practice
A 2:1 ratio on a vocal provides gentle, transparent control; an 8:1 ratio on a drum bus delivers aggressive limiting that significantly shapes the character of the performance.
Common Confusion
A higher ratio is not always more obvious. With a high threshold, even a 10:1 ratio may rarely engage and remain transparent. With a low threshold, a 2:1 ratio can crush a track. Ratio without threshold context is meaningless — they always need to be read together.
Sources & Verification
- Giannoulis, D., Massberg, M. & Reiss, J. D. — Digital Dynamic Range Compressor DesignJournal of the Audio Engineering Society, 2012
- Owsinski, B. — The Recording Engineer's Handbook (4th ed.)Bobby Owsinski Media Group, 2017
Last verified: 2026-05-05