Mixing and mastering · updated 2026-08-16

COMPRESSION

Automatic level control: above a threshold, gain is reduced by a ratio, shaped by attack and release times.

Mixing and mastering — A Solid State Logic Matrix mixing console with channel strips, faders and pan pots — the desk layout behind the gain, EQ and balance terms in this section.

Key takeaways

Automatic level control: above a threshold, gain is reduced by a ratio, shaped by attack and release times.
Slow attacks let transients through and sound punchy; fast attacks control peaks and sound controlled.
On a vocal, 3:1 with a medium attack and 3–5 dB of gain reduction on the loudest phrases keeps the performance sitting in one place.
Watch out: chasing a gain-reduction number rather than listening.
Sits under mixing and mastering in this glossary, with 2 primary sources below.

Quick checklist

Can you define compression in one sentence without looking?
Can you point at compression in a real session, mix or contract?
Have you tried the practical move above at least once?
Would you catch the common mistake before it costs you a take?
Have you opened one of the primary sources below rather than a forum thread?

COMPRESSION IN DEPTH

A compressor reduces dynamic range by turning down signal above a threshold, set by ratio, attack, release and knee. Slow attacks let transients through and sound punchy; fast attacks control peaks and sound controlled. Makeup gain restores the level you removed, which is why compression is usually perceived as louder rather than quieter.

How it works in practice

On a vocal, 3:1 with a medium attack and 3–5 dB of gain reduction on the loudest phrases keeps the performance sitting in one place.

The mistake people make

Chasing a gain-reduction number rather than listening. Two compressors doing 2 dB each usually beat one doing 8 dB.

WHERE COMPRESSION SITS

Compression belongs to mixing and mastering in the Sampled music glossary. The processing vocabulary, plus the loudness standards streaming services actually measure you against.

TERMS THAT DEPEND ON COMPRESSION

WAV vs FLAC vs MP3/AAC
WAV is uncompressed PCM; FLAC is lossless compression; MP3 and AAC are lossy. Deliver lossless masters and let platforms encode.

TEST YOURSELF

0/3 answered · 0 correct

3 quick questions on compression. Answers are marked instantly — nothing is sent anywhere.

1. Which statement best describes compression?
2. What is the mistake people most often make with compression?
3. In practice, which of these applies to compression?

Ready for the full thing? Take the 25-question terminology test and get a certificate with your name and score.

SOURCES AND CITATIONS

Free, primary references for compression — standards bodies, manufacturers, government offices and university course material. Each one lists the line of this entry it backs up.

Universal Audio — compression basics (opens in a new tab)
Primary reference · uaudio.com
“Automatic level control: above a threshold, gain is reduced by a ratio, shaped by attack and release times.”— the claim this source supports
Why it counts: Published by the organisation responsible for the thing being defined, so it is a first-hand source rather than a summary of one.
AES technical library (opens in a new tab)
Professional standards body · Audio Engineering Society
“A compressor reduces dynamic range by turning down signal above a threshold, set by ratio, attack, release and knee.”— the claim this source supports
Why it counts: AES writes and reviews the engineering standards and peer-reviewed papers this terminology comes from.

RELATED TERMS IN MIXING AND MASTERING

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