## Compressor Types, Their Best Uses, and Mixing Strategies As an audio engineer preparing for a mix, understanding different compressor types is essential. Each type has its unique characteristics, making it suited for specific tasks in shaping dynamics. ## VCA (Voltage Controlled Amplifier) Compressors **Best For:** • Drums (Kick, Snare, Drum Bus) • Vocals (Especially aggressive or controlled vocal performances) • Mix Bus & Master Bus (Glueing mix elements together) • Bass (Tightening the low end) ## Starting place for use in a mix: • **Drums:** Use a **medium attack (5-15ms)** and **fast release** for punch and energy. Ratios between **4:1 to 10:1** work well for aggressive control. • **Vocals:** Great for transparent leveling with a **low ratio (2:1 to 4:1)** and **medium attack/release** to maintain natural dynamics. • **Mix Bus:** A **low ratio (1.5:1 to 2:1)** with **slow attack and auto release** to subtly glue the mix. ### Examples: • SSL G-Series Bus Compressor (for mix bus glue) • API 2500 (punchy drums and transient shaping) • DBX 160 (tight bass and snare control) --- ## Optical Compressors **Best For:** • Vocals (Smooth and warm compression) • Acoustic Instruments (Guitars, strings) • Bass Guitar (Natural leveling) • Mix Bus (Subtle dynamics control) ### Starting place for use in a mix: • **Vocals:** A **slow attack and release** makes them smooth and warm. A **ratio of 3:1 to 5:1** works well. • **Bass Guitar:** Keeps low-end even without squashing. **4:1 ratio with medium attack/release**. • **Mix Bus:** Transparent dynamic control with a **low ratio and gentle compression (1-2dB of gain reduction).** ### Examples: • Teletronix LA-2A (legendary for vocals and bass) • Tube-Tech CL1B (clean and smooth vocal compression) --- ### FET (Field Effect Transistor) Compressors **Best For:** • Drums (Punchy and aggressive) • Rock & Pop Vocals (Exciting, fast compression) • Guitars (Especially distorted guitars) • Parallel Compression (Adding energy and thickness) ### Starting place for use in a mix: • **Drums (Snare/Kick/Toms):** Fast attack and release for aggressive punch. **4:1 to 8:1 ratio** for snap. • **Vocals:** Great for rock/pop vocals. Use **medium attack, fast release** for presence and excitement. • **Parallel Compression:** Blend a heavily compressed track back in with the original for thickness. ### Examples: • Urei/Universal Audio 1176 (Fast, punchy compression) • Purple Audio MC77 (Modern 1176-style with more control) --- ## Vari-Mu (Variable Mu) Compressors **Best For:** • Mix Bus & Mastering (Glue and warmth) • Vocals (Natural leveling) • Strings, Pads & Soft Instruments (Musical, smooth compression) **How to Use in a Mix:** • **Mix Bus:** A **low ratio (1.5:1 to 2:1)** with **slow attack and release** smooths dynamics naturally. • **Vocals:** Helps add weight and warmth with a **low ratio and soft knee**. • **Mastering:** Transparent compression, subtly gluing everything together. ### Examples: • Manley Variable Mu (Mastering-grade glue) • Fairchild 670 (Classic tube warmth) ### Choosing the Right Compressor in Context | **Compressor Type** | **Best For** | **Example Plugins/Hardware** | | ------------------- | ---------------------------------- | ------------------------------- | | **VCA** | Drums, Mix Bus, Vocals | SSL G-Series, API 2500, DBX 160 | | **Optical** | Vocals, Bass, Acoustic Instruments | LA-2A, Tube-Tech CL1B | | **FET** | Punchy drums, Rock vocals, Guitars | 1176, Purple Audio MC77 | | **Vari-Mu** | Mastering, Mix Bus, Smooth vocals | Manley Vari-Mu, Fairchild 670 | --- ## Final Mixing Ideas and Tips 1. **Layer Compression** – Use a combination of compressors for control and character (e.g., 1176 for snap, then LA-2A for smoothness on vocals). 2. **Parallel Compression** – Blend in heavily compressed tracks subtly to retain transients and dynamics. 3. **Use Attack & Release Wisely** – Slower attack for punch, faster attack for tighter control. 4. **Listen for Artifacts** – Over-compression can suck the life out of a mix; always A/B your settings. 5. There are no "right" answers. Don't be afraid to experiment and have fun trying different types across your recordings.