It’s no secret that dynamic range compression is one of the most important and versatile tools to an audio engineer. Here’s information on some of the ways that you can use the many different types of compression to enhance your productions.
1. Multiband Compression/Limiting
Multiband compression allows one to affect the dynamic range of multiple frequency ranges independently of one another. Want to tame the beater of a kick drum without altering the low end? No problem. Simply choose a frequency range, and then set threshold, attack and release like you would on a normal compressor.
Practical applications: Master bus for clearing up problem areas like low-mid buildup, or on lead vocals to tame harshness in the 5-10k range.
Recommended plugins: FabFilter Pro-MB, iZotope Ozone 6, Waves L3-LL Multimaximizer
2. Lookahead Compression
Lookahead compression essentially analyzes an input signal and applies compression before the signal is audible, allowing one to tame transients in a unique way. Lookahead compression can be achieved with a standard compressor by duplicating the signal onto another track in your DAW, moving the audio back in time, placing a compressor on the original signal, and using the duplicated audio as the sidechain input.
Practical applications: Really anything with prominent, fast transients but especially effective on snare drum and vocals.
Recommended plugins: Softube FET compressor, Waves C1 Compressor with Sidechain
3. Brickwall Limiting[Disclaimer] Learn how to mix before simply applying a brickwall limiter to the master bus of all your productions.
Although arguably the catalyst for the Loudness War, which stripped certain popular music of dynamics for over a decade, brickwall limiting certainly has its place in music production, live sound reinforcement and broadcast. Set the ceiling, and your signal will never go above it. Alter the threshold to bring the lower amplitude of the dynamic range closer to the top, allowing one to reach professional-level RMS without understanding professional-level mixing skills. [see disclaimer!]
Practical applications: Pre-mastering if used properly and mastering. Use on sub-auxiliary tracks to achieve higher RMS values before even hitting the master bus. Can be used on individual tracks to tame transients or shape tone just like a traditional compressor.
Recommended plugins: FabFilter Pro-L, Waves L2, PSP Xenon
4. Sidechain Compression or Ducking
The sound of a side-chained synthesizer and kick drum is instantly recognizable. Essentially, it involves using one signal to apply compression upon a another. There are plenty of online tutorials for this process, but the applications below may be ones you’re less familiar with.
Practical applications: Use the signal of vocals to duck drums or guitars to allow the vocal to sit more prominently in the mix, use a sample to replace or augment originally recorded cymbals, use a cowbell or tick sample rather than the kick to duck synth (due to the faster attack of the tick sound.)
Recommended plugins: Softube CL1B or Valley People Dyna-mite, Waves H-Comp or API 2500
5. Parallel Compression
Parallel compression (sometimes referred to as New York compression) is great for keeping the original, natural sound of a recording, while still enjoying the benefits of a compressed signal. Simply route your signal to an auxilliary track (via the sends, not output) apply compression, and blend in the aux track to taste. Be aware of delay compensation settings in your DAW to avoid unwanted phase issues.
Practical Applications: Very popular on drums or signals with harsh transients. Also great on the master bus for achieving a boost in RMS.
Recommended plugins: Certain plugins like Cytomic’s The Glue or FabFilter’s Pro-L allow for a dry/wet blend which can achieve similar results to parallel, but any of your favorite compressors can achieve great results if used properly.