Parallel processing is a common concept in advanced mixing. A basic description for it would be the process of duplicating a sound source, processing the duplicate independently, and then balancing or blending the duplicate with the original audio signal. This allows you to be more creative and extreme with effects. Options are quite versatile. In the next tutorial, we will share five useful tips to keep in mind when using parallel processing in your mixes.
Be aware of latency when parallel processing
There is a risk of unfavorable phasing by using parallel processing. This occurs as a result of plug-in latency. In essence, applying plugins to your duplicated signal generates a small amount of time delay or latency. This is caused by the time it takes the plugin to process the signal. Phasing, or in extreme cases, slapback may occur when the delayed signal is merged with the original. This is something you want to avoid. Fortunately, many modern DAWs provide automatic delay compensation to address this problem. This function keeps a constant time delay synchronized across all tracks. Just make sure the option is enabled.
Experiment with pre/post fader
Most modern DAWs offer pre/post fader settings for signals sent to the auxiliary or return tracks. A pre-fader send splits, or copies the signal before the track’s fader increases or lowers its volume, making the send independent of that fader’s level. On the other hand, a post-fader send copies the signal after the track’s fader, making the send dependent on that fader level.
It is often advantageous to use a pre-fader send while mixing with parallel processing. This is because the signal would be essentially independent of the channel fader, allowing you to raise or lower it without affecting the level sent to the auxiliary track.
Know when to avoid parallel processing
Regardless of the advantages parallel processing offers, there are times when it can be a bad idea. For instance, when dealing with vocals, you’d want to be cautious. Vocals will have unedited breathing as a natural part of the performance. When they are overly compressed, it often makes the breaths louder, which can be irritating. For that reason, on your parallel track, you might want to use a gate effect before the main compressor. That can prevent this problem. Set it so that it only allows the actual vocals to cut through to the compressor, and not the breathing.
Use an EQ in tandem with the compressor
Quite often, when using parallel compression you may only want to bring out certain frequencies. This is because otherwise parallel compression could amplify problem frequencies that you don’t want to hear. Adding an equalizer plugin before or after the compressor would be the solution. With it, you can cut out any obnoxious frequencies and raise the ones that enhance the sound. Keep in mind that putting an EQ in front of a compressor will change how it responds to the sound it receives.
Use multiple parallel compressors
Contrary to popular belief, you don’t need to restrict yourself to using this method on an audio signal just once. When using parallel processing on vocals, for example, sending the vocal track to multiple separate channels and using a different compressor on each can be extremely beneficial. This relates to the concept of using parallel compression as a sort of EQ. Each parallel channel will have its own distinct characteristics, which you can mix to achieve the desired vocal tone.