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September 24, 2020

Sidechain compression on vocal delays




The song “Some Summer Day” by Six of One has a distinctly psychedelic vibe, so it’s fitting that Fab decides to use what he terms a “trippy delay” on it. In this excerpt from Pro Member Mix Fix: Six Of One - Episode 3: Tweaking The Song Structure, he shows how to set up a delay that’s ducked with sidechain compression..

Get it Going

The delay is a relatively long one, which he’ll apply to the background vocals in the second verse to add variation and spice to the mix. To create it, he starts by adding a stereo Aux track to his Pro Tools session. He inserts Soundtoys EchoBoy on the new Aux track. He then opens a send on the harmony vocal track—a stereo mix of the background vocals—to feed the delay.

Fab uses SoundToys EchoBoy with these settings for the delay.

After listening to how it sounds on the vocals, he says he hears it with a flanger added the delay. He opens an instance of Avid’s Flanger plug-in in the insert slot right after EchoBoy.

Side by Sidechain

Fab says he doesn’t want the delay to be prominent when the singers are singing, only at the end of the vocal lines. To make that happen, he’ll use the compressor in the Sonnox Oxford Dynamics plug-in to duck the delay.

Avid’s Flanger plug-in modifies the delayed signal.


From the harmony track, he creates another send, which he names Back Key. He routes it to the sidechain input of Oxford Dynamics. The signal from the harmony vocals triggers the compressor, which Fab sets to provide about 2dB to 4dB of attenuation when the vocalists are singing, reducing the delay’s level enough to make it not noticeable.

At the end of each phrase, the sidechain signal drops out, the compressor is no longer being triggered, and the delay pops through the mix.

Fab’s compression settings.

Beat Crazy

Now that he has the effect configured, Fab experiments with the delay time. He’d initially set EchoBoy to an eighth-note delay, but he switches the value to a quarter note. He listens, then tries a quarter-note triplet, but eventually decides the eighth-note was better.

He also changes the Style setting on EchoBoy. The Style parameter offers over 30 different sound options for the delayed signal, ranging from standard digital delay to delays with various distortion, modulation and tape-echo effects. Fab opts for the setting called Tube Tape.

Alternate Methods

The sidechain compressor method that Fab used for ducking the delay is effective and consistent. However, there may be some situations where you want to totally customize where the delay comes in and which syllables or notes are getting delayed. If so, you can create a ducking effect using automation.

There are several different ways to accomplish this. We’ll look at two of them here: automating delay-send level and delay-send mute. For either method, start by creating an aux send with your delay on it.

Method one involves automating the delay send level, bringing it up at the spots where you want the taps to be clearly audible. Doing it like that allows you to have some slight delay going all the time and then bring it up each time you want the delay to be prominent.

Automating the delay-send level using touch mode.

It works best to put your automation in touch mode, and each time after you bring the fader up to accentuate the delay, release it. You’ll probably need to go in and edit your automation to get it just the way you want.

Here’s an example of that delay method on a lead guitar track.

The guitar track soloed, with the delay.

Alternatively, you could automate the mute on the delay send, unmuting it at the point you want the delay to start. This method provides for an abrupt onset of the effect. It’s particularly good for delay throws, where you want the delay taps to occur strictly on a specific note or word.

If you’re recording the automation in real time, use latch mode. That way, the mute stays off until you press it again (or you can draw in the automation).

Here’s the same passage using the “unmute the send” method.

Now, with the guitar soloed.

Using the delay-send mute to automate. The lighter areas, where the breakpoint lines is at the bottom of the screen, are where the delay send is muted .

Prepackaged Duck

Finally, if you don’t feel like dealing with automation or sidechains, you can find delay plug-ins with built-in ducking features, such as Space Duck from 2getheraudio. You won’t have as much control over the delay taps and their level as you would with the sidechain or automation methods, but you can quickly get a similar vibe.

An easy, albeit less-precise way to create a ducked delay is with a plug-in that has it built-in, such as 2getheraudio Space Duck, which also offers ducked reverb.