Compression Cheat Sheet
Compression Basics
Parameter
Description
Typical Settings
Ratio
How much compression is applied when signal exceeds threshold
2:1 to 4:1 (gentle), 4:1 to 8:1 (moderate), 8:1+ (heavy)
Threshold
Level at which compression begins
-30dB to -5dB (adjust to source)
Attack
How quickly compression engages
1-10ms (fast), 10-50ms (medium), 50ms+ (slow)
Release
How quickly compression disengages
50-200ms (fast), 200-500ms (medium), 500ms+ (slow)
Knee
How gradually compression is applied
Soft (smooth), Hard (abrupt), or variable
Common Instruments
Instrument
Settings
Purpose
Vocals
4:1 ratio, medium attack (10-30ms), auto release
Smooth dynamics, control peaks
Bass
4:1 ratio, fast attack (1-5ms), medium release (100-300ms)
Even out performance, add punch
Drums (Overheads)
2:1 ratio, medium attack (10-30ms), auto release
Glue drum kit together
Acoustic Guitar
3:1 ratio, medium attack (5-20ms), medium release (100-300ms)
Smooth fingerpicking or strumming
Compression Types
VCA
- Fast, clean, and precise
- Great for drums, bass, and mastering
- Examples: dbx 160, SSL G-Series
FET
- Fast, aggressive, adds color
- Great for drums, vocals, and parallel compression
- Examples: Universal Audio 1176, Purple Audio MC77
Optical
- Smooth, musical, slower response
- Great for vocals, bass, and mix buss
- Examples: Teletronix LA-2A, Tube-Tech CL 1B
Variable-Mu
- Warm, musical, tube-based
- Great for mix buss, vocals, and mastering
- Examples: Fairchild 670, Manley Variable Mu
Quick Tips
Parallel Compression
Blend heavily compressed signal with dry signal for punch and sustain.
Try 50/50 wet/dry blend for drums
Sidechain Compression
Use kick drum to trigger compression on bass for better low-end clarity.
Multiband Compression
Compress different frequency ranges independently for more control.