Field Guide / Audio Post
Audio Compression Without the Mystery.
Compression is not a loudness button. It is a decision about what should stay steady, what should hit, and what should get out of the way.
What Is Happening
Dynamic Range Is the Distance Between Quiet and Loud.
A compressor narrows that distance. In normal downward compression, audio above the threshold gets turned down. Then makeup gain can bring the full signal back up.
That is why a compressed voice can feel closer at the same peak level. Peaks are lower, quieter details sit higher, and the performance takes up more space.
Gain Reduction
After
Four Controls
Every Compressor Asks the Same 4 Questions.
01
Threshold
What level should trigger compression? Lower it until only the moments you care about move the gain reduction meter.
02
Ratio
How firmly should the compressor push back? 2:1 smooths. 4:1 controls. 8:1 and above starts acting like a ceiling.
03
Attack
How fast should it grab the sound? Fast attack softens the front edge. Slower attack lets the first hit pass.
04
Release
How fast should it let go? Set it so the meter recovers before the next phrase, hit, or beat.
Problem Solvers
The Extra Knobs Exist for Specific Jobs.
Makeup Gain
Adds level after gain reduction. Match bypass volume before you decide it sounds better.
Knee
Soft knee eases into compression. Hard knee reacts more directly at the threshold.
Sidechain Filter
Keeps low-end rumble from making the compressor overreact.
Lookahead
Lets a digital compressor see peaks early. Useful for clean peak control.
Mix
Blends compressed and dry signal. This is the fastest route to parallel compression.
Stereo Link
Keeps left and right channels moving together so the image does not wobble.
Workflow
Set Compression After the Recording Is Under Control.
The compressor should not be the first tool that touches a messy recording. Make the source behave first. Then ask the compressor to do less work.
- 01Clean the recording. Remove noise, clips, mouth clicks, and dead space first.
- 02Set clip gain. Bring wild words closer before the compressor sees them.
- 03EQ obvious problems. Rumble and harshness can make compression react wrong.
- 04Compress for control. Watch the meter, then close your eyes and listen.
- 05Match bypass level. Louder almost always lies.
- 06Add tone and peak safety after control is stable.
Starting Points
Settings Are Not Rules. They Are a Place to Start Listening.
Dialogue and Interviews
Goal
Keep words present without making room noise breathe.
Start
2:1 to 4:1 ratio. 10-30 ms attack. 60-150 ms release.
Move
Aim for 3-6 dB of gain reduction on loud words. Ride clip gain before the compressor.
Voiceover
Goal
Make the voice steady, clear, and close.
Start
3:1 ratio. 5-20 ms attack. 80-180 ms release.
Move
Use one compressor for control, then a limiter for final peaks. Do not let the limiter do the whole job.
Podcast Bus
Goal
Hold multiple speakers in one consistent pocket.
Start
2:1 ratio. 20-40 ms attack. 120-250 ms release.
Move
Compress individual mics first, then use light bus compression to make the conversation feel connected.
Music Under Dialogue
Goal
Let music support the voice without fighting it.
Start
Sidechain from dialogue. Fast attack. Medium release.
Move
Duck the music by 2-6 dB when the voice enters. If the duck is obvious, slow the release.
Drums and Percussion
Goal
Choose whether the hit punches or gets rounded off.
Start
4:1 ratio. Slow attack for punch. Fast attack for control.
Move
Use the release like tempo. The meter should breathe with the groove, not chatter.
Master Safety
Goal
Catch peaks without changing the whole mix.
Start
Low ratio or limiter. Slow attack unless peaks are the problem.
Move
If you see constant gain reduction on the master, fix the mix before adding more compression.
Diagnosis
If It Sounds Wrong, the Compressor Is Telling You Where to Look.
Flat and Lifeless
Attack is too fast, ratio is too high, or threshold is too low.
Pumping
Release is fighting the rhythm, or low-end energy is triggering the detector.
Room Noise Jumps Up
Makeup gain is raising the floor. Clean or expand before compression.
S Words Get Sharp
Add de-essing before or after compression, depending on where the harshness starts.
Voice Still Feels Uneven
Use clip gain or volume automation. Compression is not a replacement for judgment.
Stereo Image Shifts
Use stereo linking, reduce channel-specific gain reduction, or compress the bus less.
When to Leave It Alone
Compression Is Not Always the Answer.
If the performance already sits in place, do not add compression out of habit. If the recording has too much room, too much noise, or clipped peaks, compression may make the problem louder.
Level rides, clip gain, mic placement, and cleaner recording choices usually beat a heavy compressor. Use the tool when it solves a clear problem.