We uncover four methods of applying parallel processing, and four ways you can use the technique to improve your mixes
Whatever your music production background or sound engineering skill level, you’ve probably come across the term parallel processing. It’s a technique you’ve likely used at some point or another, whether you know it or not.
When used correctly, parallel processing has many applications and advantages. In this article, we’ll explain what parallel processing is, some different ways of applying the technique, and how you can use it to improve your mixes as well as your creative workflow.
Within the context of music production and sound engineering, parallel processing refers to the practice of mixing a processed (wet) signal with the original unprocessed (dry) signal. Although many types of audio effects can be used in parallel, one of the most well-known types of parallel processing is parallel compression. This technique is also known as New York compression thanks to the swathes of New York-based audio engineers who adopted it in the 80s and 90s.
You may have also come across the concept of using a plugin as an insert, or in serial, but how do these approaches differ from using a plugin in parallel? The term insert comes from the audio hardware world, and refers to ‘inserting’ an effect into an existing signal chain. The same is true of software effects; when you place a plugin directly on a channel and therefore into the signal chain, you are using it as an insert. Serial processing refers to inserting multiple effects one after the next in the same signal chain.
There are three main ways to apply parallel processing, plus an additional fourth method which we’ve explained below.
Some audio plugins have an integrated Dry/Wet or Mix control, offering a quick and easy way to apply parallel processing. At 0%, the plugin will only output the dry signal, and at 100%, the plugin will only output the wet signal. At any value between 0% and 100%, the plugin outputs a mix of the dry and wet signals, thus is applying parallel processing.
While this is the most straightforward method of applying parallel processing, it’s also the least flexible. Additionally, not all plugins have a Dry/Wet or Mix control, so it’s important to know the alternative ways to apply the technique.
The second method of applying parallel processing is achieved by duplicating a track and then applying processing to the duplicated signal. This grants you more control than the first method, as it allows you to blend the processed signal into the dry signal without affecting the level of the dry signal.
Using this method, you can also apply further processing to the wet signal without altering the dry signal. This method is particularly useful for applying parallel processing to a single audio source, and can be carried out with plugins that don’t have a Dry/Wet or Mix control.
You can also apply parallel processing using an aux or return channel. The terminology here varies depending on which DAW you’re using, but the terms aux and return channel are interchangeable.
After creating a new aux or return channel in your DAW, add an instance of the plugin effect you want to use. You can then ‘send’ any amount of any signal to the effect, and you can even send audio from one aux or return channel to another.
This method of applying parallel processing gives you the most control and flexibility, as you can apply further processing to the wet signal. You can also send multiple dry signals to the same aux or return channel, making this a useful mixing technique to have up your sleeve.
The fourth way to apply parallel processing is to use a plugin with a dedicated Parallel Mode. In the case of our powerful multiband dynamics processor, DynOne 3, applying parallel processing is as simple as engaging Parallel Mode in the plugin’s settings. Read on to find out more about DynOne 3’s Parallel Mode, and how you can use it to beef up drums and other instruments with ease.
Now that we’ve explained the four main methods of applying parallel compression, let’s explore some of the key uses of the technique.
One of the most popular ways in which experienced sound engineers use parallel compression is to add power and excitement to drums. Applying any sort of compression inherently reduces a signal’s dynamic range, and applying too much can result in a lifeless and unnatural mix.
This is especially problematic on particularly dynamic instruments, such as drums. The benefit of parallel compression is that you can apply extreme dynamic processing to the parallel signal, and all of the dynamic and transient content of the dry signal remains intact. The result is a drum mix that sounds both natural and impactful.
The level of control offered by DynOne 3 makes it the perfect tool for applying parallel processing to your drum mix. Switching on the built-in Parallel Mode adds each band’s compressed signal back to the dry signal. In this mode, the wet signal level for each band is controlled by the Band Faders. This makes it possible to apply multiband dynamic compression without the need for any additional channels or complex channel routing.
With five bands of dynamics processing and intelligent adaptive attack and release settings, DynOne 3 is capable of applying transparent compression to single drum parts or entire drum mixes. Download the free fully functional 30-day trial to hear how DynOne 3 enhances your drum mixes.
Parallel processing can also be used to apply additional effects to a wet signal without altering the dry signal. For example, it’s common to mix a lead vocal at the front and centre of a mix so that it retains maximum clarity. However, you might want to add further processing to the vocal to give it some more interest and character.
This can be achieved with EQ, reverb and chorus to give the vocal more space, stereo width and movement, but applying these effects as inserts will subtract from the impact and clarity of the original dry signal. Instead, you can apply these effects in parallel on an aux or return channel, thus leaving the dry signal unaltered and giving you much greater control over your vocal mix.
We’ve achieved this using two instances of our Joe Chiccarelli plugin, both placed on a single return channel and set to the Lead Vocal profile. In the first instance of the plugin, we used the built-in EQ section to attenuate the low end and emphasize our lead vocal’s high frequencies.
On the second instance of the plugin, we’ve selected one of Joe Chiccarelli’s three reverb types and engaged Reverb Only mode, giving us a completely wet reverb signal. We’ve then placed a stock chorus effect after the EQ and reverb, and blended the processed signal back in with the dry signal.
This gives us a wider and brighter vocal mix that has a natural sense of space without subtracting from the clarity of the dry signal. This technique also gives us the flexibility to automate the level of the wet signal between song sections, which can create a more exciting and dynamic overall mix.
Another practical use of parallel processing is using the same plugin or effects chain to process multiple audio signals. The first advantage of this is that it can give your mix a sense of glue and cohesion. For example, applying a subtle room reverb to your vocals, drums and guitar can give the impression that they were recorded in the same space. The result is a much more natural and cohesive mix.
The second advantage of using parallel processing in this capacity is that it reduces the number of plugins being used in your DAW project. Inserting an identical reverb on your vocal, drum and guitar parts would require three individual instances of the same plugin. Instead, you can use a single plugin on a return or aux channel to apply the same reverb to all three parts. This uses considerably less CPU power than applying every plugin as an insert, and also means you’ll only have to adjust a single plugin’s settings when configuring your effect.
For the final technique in this article, we’re heading back to DynOne 3, this time with a video from MarcoAntonio Spaventi. In the video, he demonstrates how to use the plugin’s Parallel Mode and Center and Sides modes to increase his mix’s stereo width. He discusses how applying parallel compression to the sides of the signal can make it sound louder, and therefore wider. Check out the video to see how MarcoAntonio applies the technique.
If you found this guide to parallel processing helpful, you can check out the Leapwing Audio blog page for more audio articles and how-to guides.
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