How-To: Ducked Delay

Ride the FX level without lifting a finger
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Prominent echo trails can sound great in the gaps between lead guitar and vocal phrases, but they can clutter up the tracks when they are currently voicing if the effect is too loud. To quiet the echoes here and there, you can place the plug-in producing them (set to 100%-wet output) on an aux and ride the aux’s fader or the dry track’s send. Or, if the plug-in is instantiated on the track’s insert, you can ride the plug-in’s wet/dry mix control(s). Either way, you’ll need to write automation to record and playback all of your manual moves. What a hassle!

Instead, why not use an effect that adjusts its wet signal level automatically? Ducked delay does just that. This type of effect uses a built-in ducker to attenuate the effect’s wet signal—by an amount you choose—when its dry input signal exceeds the threshold level you set. By setting the threshold slightly lower than the level that an instrument is playing or a vocalist is singing, you make the ducker automatically lower the level of the delay effect when the track is voicing. An attack control determines how quickly the effect is attenuated. In between instrument or vocal phrases, the ducker releases its action and the effect’s level rebounds—at a rate determined by a release or decay control’s setting.

At the time of this writing, I knew of only three delay plug-ins that included a ducker. Let’s take a look at them, in alphabetical order. I’ll focus primarily on the plug-ins’ ducking facilities, but keep in mind they comprise only a tiny portion of the great features each of these unique plug-ins offers.


BIAS Delay resides inside Positive Grid’s BIAS Pedal plug-in, which serves as a wrapper for Distortion, Delay, and Modulation component effects (separate products). While BIAS Pedal’s main target application is processing electric guitar (the plug-in includes an amp sim, which can be bypassed), there’s no reason you can’t use the BIAS Delay component on other types of instruments and lead vocals.

Fig. 1. BIAS Delay is a component effect you select from a pop-up menu in the top left corner of the GUI for Positive Grid’s BIAS Pedal plug-in. Controls for BIAS Delay’s Ducker appear at center-left when you click on the mod stage module in the signal chain shown near the top of the GUI.

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Inside BIAS Delay’s GUI, controls are allocated to different processing modules in the signal chain (see Figure 1). You can set the delay time, feedback level, and wet/dry mix in either the Custom Panel or Delay Stage module, which duplicate controls for those parameters. The Modulation Stage is where controls for the Ducker (and for adjusting modulation and basic reverb parameters) are located.

The Threshold control sets the level above which the Ducker will kick in and reduce the level of the delay effect; turn it counter-clockwise to raise the threshold. Turn the Gain Reduction knob clockwise to increase how much the Ducker will dip the delay’s wet level; the Attack control adjusts how quickly the wet level will decrease when the threshold is exceeded. If you find the delay effect’s level rebounds too quickly after the dry signal falls below the threshold, turn the Release control clockwise. Helpful Wet Volume meters show you the current amount of gain reduction for the effect.


The PSP stompDelay plug-in offers both conventional delay effects and a looper. After setting the delay time and feedback amount, you can adjust the dry and wet signal levels independently using two controls dedicated to that purpose. The modulation section lets you select among ten different waveforms for its LFO and a whopping 37 different note values (from 64th-note triplets to several whole notes spanning up to four seconds). PSP stompDelay can also simulate the effect of a tape recorder fast-forwarding or rewinding your track.

Fig. 2. The PSP stompDelay plug-in features an effective Ducker, albeit one with limited controls and metering (situated in the bottom-right corner of the GUI). The plug-in’s other features—including a powerful modulation section—are arguably its strongest selling points.

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The Ducker section is straightforward, with two controls—Ducker Threshold and Ducker Range—doing all the heavy lifting (see Fig. 2). Adjust the latter control to set how much the wet signal will be attenuated when the input signal exceeds the threshold.

PSP stompDelay is the only plug-in of the three here that lets you dynamically attenuate the wet signal up to-∞ for complete suppression (although UVI Relayer comes so close it’s almost moot). PSP stomp-Delay’s Ducker provides no attack or release control, nor a gain reduction meter. But a helpful LED lights when the Ducker is attenuating wet signal.


Fig. 3. Clicking on the FDBK/DYN tab in the bar running along the top-center of UVI Relayer’s GUI brings up controls for a full-featured Ducker.

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Relayer is one of the most full-featured delay plugins I’ve seen. It’s a multitap delay that offers up to 32 delay lines with an adjustable diffusor (which softens the sound) and modulation controls (see Figure 3). Powerful facilities let you change the delay time, gain, pan, feedback, and filter effects (biquad filter, wah-wah, etc.) for each delay line in a multitap setup. You can process the delay effects further using supplied IRs (impulse responses), which are derived from instrument amps, radios, telephones, laptop speakers, and more. There’s even a gate you can open using a mouse click to let input signal enter the delay lines—useful, for example, for applying delay to select lyrics.

Of the three plug-ins featured here, Relayer provides the greatest complement of controls for its ducking effect. You can adjust not only the attack and decay (release) times for the Ducker but also its hold time. The hold time—adjustable up to 1,000 ms—delays the onset of the release phase in which the level of the delay effects starts to rebound. The Threshold and Amount (gain reduction) controls are also extremely wide-ranging—as low as-100 dBFS for Threshold and up to 50 dB for Amount. A simple (Gain-) Reduction Level Meter gives you a rough visual indication of how intensely the wet signal is currently being attenuated.

Ducked delay not only sounds cool, it makes production more fun by sparing you the hassle of automating effects levels. It’s an effect and technique that should be a part of everyone’s, ahem, delay tactics.

Michael Cooper is a recording, mix, mastering and post-production engineer and a contributing editor for Mix magazine. You can reach Michael at and hear some of his mixes at