Duet
Key Features
- Synchronous overlap-and-add pitch shifting preserves timing while altering pitch, avoiding the time-smear artifacts of chorus and flanger effects
- Independent left/right channel pitch shifting with configurable delay and pan on each voice for a convincing multi-performer illusion
- Real-time processing with no latency compensation required, equally useful at the tracking and mixing stages
- Pitch modulation mode doubles as a smooth, natural-sounding chorus for synths and melodic instruments
- Turns a single vocal or guitar performance into a layered ensemble texture without re-recording
- Works across vocals, electric guitars (wall-of-sound stacking), acoustic guitar, and polyphonic instruments
- Lightweight standalone 32-bit VST — only the DLL and its Resources folder required, no installer
Description
Duet is a double-tracking and harmonizer effect that thickens vocals, guitars, and instruments by creating pitch-shifted stereo doubles in real time. It uses a synchronous overlap-and-add algorithm that moves pitch independently from time, preserving the natural timing of the original performance.
The plugin processes each stereo input independently, pitch-shifting each channel and then delaying and re-panning the results to create a convincing multi-voice illusion from a single source. Traditional modulation effects like flangers and phasers alter both pitch and timing simultaneously, which introduces a synthetic, swirling quality.
By decoupling pitch from time, Duet produces natural-sounding results on electric guitars — adding instant wall-of-sound density — while keeping acoustic guitar and vocal tracks sounding organic. Users have described it as similar in character to the Eventide Harmonizer, famous for the big doubling sounds on Bowie and Led Zeppelin recordings.
A pitch modulation mode also lets the plugin function as a smooth chorus, adding movement and shimmer to synths and sustained instruments. The plugin is no longer maintained by its original developer but remains a respected tool among producers who need natural-sounding ADT without reaching for a paid solution.
Frequently Asked Questions
Why is there no GUI visible — only colored text on a black background?
This happens when the Resources folder is not placed in the same directory as the Duet.dll. Move the Resources folder into the same VST folder as the DLL, then restart your DAW. The full graphical interface will appear once both files are co-located.
Does Duet work in 64-bit DAWs?
Duet is a 32-bit VST2 plugin. Most modern 64-bit DAWs including FL Studio, Reaper, and Mixcraft can load it through their built-in 32-bit bridge layer. Some hosts may require a dedicated bridging utility such as jBridge. There is no native 64-bit version available.
How does Duet differ from a standard chorus or flanger?
Standard chorus and flanger effects modulate both pitch and time together, which creates an audible swirling or comb-filtering artifact. Duet uses a synchronous overlap-and-add technique that decouples pitch from time, so pitch can be shifted or modulated without changing the duration of the audio. The result sounds closer to a real second performance than a modulated copy.
Is this plugin still actively supported?
Martin Eastwood Audio's official website has been offline since around 2013, and Duet has not been updated since version 1.0. The plugin is now hosted by Rekkerd.org with the original developer's permission. No technical support is available, but the plugin remains functional as a free Windows VST.
