What is Compression?
Audio compression (dynamic range compression) reduces the volume difference between the loudest and quietest parts of a recording. This makes speech consistently audible without extreme volume swings—essential for podcast listening in varied environments.
How Compression Works
A compressor monitors audio level and reduces gain when it exceeds a threshold:
Input: Quiet passages at -30 dB, loud passages at -6 dB (24 dB range)
After 4:1 compression: Quiet at -30 dB, loud at -12 dB (18 dB range)
After makeup gain: Quiet at -24 dB, loud at -6 dB (18 dB range, louder overall)
Compression Parameters
| Parameter | What It Does | Podcast Setting |
|---|---|---|
| Threshold | Level where compression starts | -18 to -12 dB |
| Ratio | How much to reduce | 2:1 to 4:1 |
| Attack | How fast compression engages | 10-30 ms |
| Release | How fast compression stops | 100-300 ms |
| Makeup Gain | Volume boost after compression | As needed |
Compression Ratios Explained
| Ratio | Effect | Use Case |
|---|---|---|
| 2:1 | Gentle, transparent | Natural speech |
| 4:1 | Moderate, noticeable | Consistent voice |
| 8:1 | Heavy, obvious | Aggressive leveling |
| 10:1+ | Limiting | Preventing clipping |
For podcasts: 2:1 to 4:1 ratios maintain natural speech dynamics while controlling extremes.
Types of Compression
| Type | Character | Best For |
|---|---|---|
| VCA | Transparent, precise | Dialog, voice |
| Optical | Smooth, musical | Natural compression |
| FET | Fast, punchy | Aggressive sound |
| Multiband | Frequency-specific | Problem-solving |
Before vs After Compression
Uncompressed speech problems:
- Soft words disappear in car noise
- Loud words are jarring on headphones
- Listener constantly adjusts volume
- Inconsistent presence throughout episode
Well-compressed speech:
- Consistently audible in any environment
- Natural-sounding dynamics preserved
- Comfortable listening experience
- Professional broadcast quality
Why It Matters
Podcast listeners consume content in challenging audio environments—cars, public transit, walking outside. Compression ensures your voice cuts through without becoming exhausting.
Why compression is essential for podcasts:
-
Environmental competition: A 20 dB dynamic range might work in a quiet room but fails against road noise.
-
Passive listening: Unlike music, podcasts compete for attention. Quiet passages get lost.
-
Varied playback systems: Earbuds, car speakers, and laptop speakers all have different dynamic capabilities.
-
Listener convenience: Nobody should need to ride the volume knob throughout your episode.
The compression balance:
| Too Little | Too Much |
|---|---|
| Quiet parts inaudible | Fatiguing to listen to |
| Volume jumps around | Sounds unnatural, robotic |
| Unprofessional | Over-processed |
| Loses listeners in noisy environments | Loses listeners through fatigue |
The transparency goal: Good podcast compression should be invisible—listeners shouldn't notice it's there, only that your voice sounds consistently present and professional.
Compression vs. LUFS normalization:
- LUFS normalization adjusts overall loudness
- Compression controls the dynamic range
- Both are typically needed for professional podcast audio