Audio Compressor on Android: Threshold, Ratio, Attack, and Release Explained
An audio compressor reduces level above a threshold according to a ratio. Attack controls how quickly gain reduction starts; release controls how quickly it lets go; knee changes how gradually compression begins; makeup gain raises the result afterward. Compression can control uneven peaks, but excessive settings flatten transients, pump with bass, raise noise, and clip after makeup gain.
Compression changes range, not just volume
A compressor turns down the loudest portions relative to quieter ones. At a 4:1 ratio, four decibels above threshold become roughly one decibel at the output before makeup gain. The threshold and signal level determine whether it acts at all; ratio alone does not describe the sound.
- Threshold decides where gain reduction begins.
- Ratio decides how strongly level above threshold is reduced.
- Attack and release shape transients and pumping.
- Makeup gain is a separate output stage that can consume the recovered headroom.
Build the compressor transfer curve
Adjust threshold, ratio and makeup gain. The graph calculates output for every input level, peak compression and whether makeup gain crosses the digital ceiling.
Output at a 0 dBFS input
-10.5 dBFS
Compression at the peak
13.5 dB
Next move
What each compressor control changes
| Control | Lower / faster | Higher / slower | Listen for |
|---|---|---|---|
| Threshold | More of the signal is compressed | Only louder peaks trigger | How often gain reduction moves |
| Ratio | Gentler level control | Stronger peak reduction | Flattened dynamics at extreme values |
| Attack | Catches transients sooner | Lets initial impact through | Dull versus punchy attacks |
| Release | Recovers quickly | Holds reduction longer | Pumping versus sluggish recovery |
| Knee | More abrupt transition | Smoother transition | How obvious onset feels |
| Makeup gain | Quieter final output | Louder final output | Noise and post-compressor clipping |
A controlled starting workflow
- 1
Start with makeup gain at zero
Judge compression before loudness compensation. Louder output can disguise a worse setting.
- 2
Lower threshold until only intended peaks trigger
Watch gain reduction and listen for when the compressor begins acting too often.
- 3
Use a moderate ratio
Begin around 2:1 to 4:1 for control rather than immediately treating the compressor as a limiter.
- 4
Tune timing with transient material
Use drums, plucked instruments or speech. Faster attack softens leading edges; release that is too fast can pump with low frequencies.
- 5
Add makeup gain within headroom
Level-match bypass and processed output, then leave margin for later EQ and system stages.
Makeup gain still needs headroom
Combine the largest positive gain and preamp value to see whether the dynamics stage can cross the digital ceiling.
Estimated peak above ceiling
2.0 dB
Remaining digital headroom
0.0 dB
Reduce
Place the compressor before the final output
Model source peaks, EQ and output gain with a limiter ceiling. This exposes clipping that can happen after a well-configured compressor.
Peak before limiting
+4.0 dBFS
Above digital ceiling
4.0 dB
Limiter gain reduction
5.0 dB
Extra output gain: -1.0 dBFS
Next move
Compressor, limiter, normalization, or volume?
Compressor
Reduces dynamic range above a threshold using a chosen ratio and timing.
Limiter
Uses a very high ratio near a ceiling to prevent peaks from passing a set level.
Normalization
Applies track or program gain toward a loudness target; it is not continuous transient compression.
Volume control
Moves the entire signal level without automatically changing the difference between quiet and loud passages.
Audio compressor questions
What is a good compressor ratio?
There is no universal value. A moderate 2:1 to 4:1 ratio is a useful learning range; the threshold, timing and source determine the actual reduction.
Why does compression make bass pump?
Strong low-frequency peaks can repeatedly trigger gain reduction. A release that recovers at the wrong speed makes the whole mix audibly rise and fall.
Is a compressor the same as a limiter?
No. A limiter is an extreme form of dynamics control designed around a ceiling. A compressor normally uses a lower ratio for broader range shaping.
Does makeup gain restore dynamics?
No. It raises the compressed result but does not recreate the original peak-to-quiet contrast. It can also cause clipping later.
Should I compress every song on Android?
No. Many releases are already heavily processed. Use compression for a specific problem, compare at equal loudness and keep an unprocessed reference.