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STELLARR

Introduction

What is Stellarr?

Stellarr is an open-source signal processing application for musicians. It lets you build custom audio chains using your existing VST3 and Audio Unit plugins, arranged on a visual grid with flexible routing, states, scenes, and MIDI control.

Think of it as a virtual pedalboard and amp rack that you design yourself, using any plugins you already own.

Philosophy

Stellarr was made by an AI and a human, together. It is free and open, forever. For the love of all human expression.

We believe:

  • Musicians should own their signal chain. Your plugins, your routing, your presets. No vendor lock-in.
  • Simplicity enables creativity. A clean, focused interface that gets out of your way so you can focus on your sound.
  • Live performance matters. Scenes, states, and MIDI control are first-class features, not afterthoughts.

Core Concepts

Blocks

Everything in Stellarr is a block. There are three types:

  • Input – receives audio from your audio interface
  • Output – sends audio to your speakers or headphones
  • Plugin – hosts a VST3 or Audio Unit plugin (amp sim, effect, etc.)

Blocks live on a grid and are connected by wires that carry audio and MIDI.

States

Each plugin block can save up to 16 states. A state is a snapshot of:

  • The plugin’s internal settings (knobs, switches, presets)
  • The block’s parameters (mix, balance, level, bypass, bypass mode)

Switch between states to instantly recall different configurations of the same plugin.

Scenes

A scene is a preset-level snapshot of which state is active on every block, plus each block’s bypass status. Use scenes to switch your entire rig between verse, chorus, solo, or any configuration – in one click.

Presets

A preset is a complete session file (.stellarr) containing:

  • All blocks and their positions on the grid
  • All connections between blocks
  • All states per plugin block
  • All scenes
  • MIDI CC mappings (preset-level)

MIDI Control

Map any MIDI CC to any parameter: block bypass, mix, balance, level, scene switching, and more. Use MIDI Learn to auto-detect your controller’s CCs, or assign them manually.

Most MIDI mappings are saved with the preset and switch when you change presets. Two are global – they live in app settings and survive preset switches and restarts: Preset Change (Program Change selects a preset by index in the active folder) and Tuner Toggle (a CC activates the chromatic tuner and switches the UI to the Tuner tab). See MIDI for the full target list.