I wanted a pitch-correction plugin that I could use for live vocals without buying another license or adding a large processing delay. So I built Simple Live Tune.

It is a free, open-source plugin for macOS and Linux. The current macOS release includes Audio Unit and VST3 plugins plus a standalone app. The source also builds VST3, CLAP, and the standalone app on Linux.

The plugin takes a vocal signal, detects the sung note, and moves it toward the nearest note in the selected key and scale. It can correct gently or produce the hard, obvious effect people usually associate with autotune.

Why another tuning plugin?#

I built Simple Live Tune for the same environment that led to SimpleAUHost: small live productions run by volunteers. The technical setup should happen before the event. During the show, the operator should only need to choose a song, check its key, and switch tuning on or off.

Commercial plugins can do this job well. I still wanted an option that I could change myself, integrate directly with SimpleAUHost, and give to another church without asking them to buy the same software first.

Simple Live Tune is not trying to cover every studio workflow. It corrects live vocals, exposes the controls needed for that job, and saves its state with the host session.

What zero latency means here#

Audio software is a little slippery with the word “latency,” so this needs a qualifier. Simple Live Tune adds no latency to the audio path. It does not put the full audio signal through a large analysis buffer before producing output.

Pitch detection still takes time. The detector analyzes a trailing window of audio and uses that result to control the current pitch shifter. This creates a short reaction time before correction follows a new note, but it does not add the same fixed delay to the audio path.

Controls that matter live#

The Key and Scale controls define the allowed notes. Major, minor, and chromatic scales are available. The rest of the controls adjust how the plugin reacts:

  • Retune Speed controls how quickly correction settles within a note.
  • Note Transition controls the movement between target notes.
  • Correction sets the overall correction amount.
  • Vibrato preserves more of the singer’s pitch movement.
  • Tolerance leaves small pitch differences alone.
  • Confidence and Gate stop breaths, background noise, and uncertain pitch from triggering correction.
  • Bypass turns correction off while keeping the plugin loaded.

The display shows the detected note and its distance from the target. It also plots the original and corrected pitch over the last few seconds. That has been useful while setting the gate and confidence threshold because I can see when the detector starts following room noise instead of the singer.

SimpleAUHost integration#

SimpleAUHost recognizes Simple Live Tune instances and controls them from its Perform view. An operator can change the key, scale, retune speed, note transition, and bypass state without opening the plugin editor.

Setlist changes can apply the next song’s key to every supported tuning track at once. The same controls are available through the SimpleAUHost control API and its Bitfocus Companion module, so a Stream Deck can operate the tuning setup too.

The integration is the main reason I wanted control over both sides. Parameter names and behavior do not need a compatibility layer that guesses what a plugin means. SimpleAUHost knows exactly which Simple Live Tune parameter to change.

Download and install#

Simple Live Tune is available as a universal macOS download for Apple Silicon and Intel Macs on macOS 11 or later. The archive contains AU, VST3, and standalone builds.

The release is not notarized by Apple yet. macOS may block it on first launch, so the archive includes installation and Gatekeeper instructions. Only approve the plugin if you downloaded it from the project’s GitHub release page and trust it.

Linux users can build VST3, CLAP, or the standalone app from source. Build instructions are in the README.

Simple Live Tune is licensed under the GNU General Public License v3.0 or later. Autotalent and zita-at1 inspired the approach.