Mixing is a game of compromise. If you want a vocal to be "thick" and "powerful," you usually have to use heavy compression, but that can destroy the delicate "breath" and dynamics of the performance. If you want a snare to be "punchy," you might use distortion, but that can make it sound messy.

The solution is Parallel Processing. Instead of putting effects directly on your track, you create a "copy" of the signal, process that copy aggressively, and then blend it back with the original, clean sound. It is the best of both worlds.

1. Parallel Compression (New York Style)

This is the most famous form of parallel processing. It involves sending your drums (or vocals) to a separate bus and using a compressor with a very high ratio (10:1) and a fast attack to literally "crush" the transients.

On its own, this crushed signal sounds terrible. But when you blend it in underneath your original, "dynamic" drums, it adds a massive amount of "weight" and "density" while the original signal provides the "snap" and "punch."

2. Parallel Saturation

Saturation adds harmonics and "edge" to a sound. However, putting a distortion plugin directly on a bass guitar can make it lose its sub-bass definition. By using a parallel bus, you can distort only the mid-range of the bass, providing grit and character, while the original track keeps the low-end clean and powerful.

3. Parallel Reverb and Delay

Technically, any time you use an "Aux Send" for your reverb, you are doing parallel processing. This is far superior to using a "Mix" knob on the track because it allows you to EQ the reverb independently. You can high-pass the reverb so it doesn't muddy the kick, or add a bit of "shimmer" without making the dry instrument sound too bright.

4. How to Set This Up in Your DAW

1. Create a New Aux / Bus Track.
2. Use the "Send" on your instrument track to feed signal into this bus.
3. Add your aggressive effects (Compressor, Saturation, Exciter) to the bus.
4. Turn the volume fader of the bus all the way down.
5. Slowly bring the fader up until you hear the sound "fill out." Stop just before it becomes too obvious.

5. The Danger: Phase Issues

Parallel processing involves combining two identical signals. If your plugin adds a tiny bit of "latency" (delay) to the processed signal, they will fight each other, causing Phase Cancellation. This usually makes the sound feel "hollow" or "weak."

The Fix: Most modern DAWs (Logic, Ableton, Pro Tools) have "Delay Compensation." Ensure this is turned on so that your parallel signals stay perfectly aligned down to the millisecond.

Summary

Parallel processing is the difference between a mix that sounds "processed" and one that sounds "powerful." It allows you to be as aggressive as you want with your effects without ever losing the natural "life" of the recording. Try it on your next vocal or drum group, and you'll never go back to "inserts" again.