NoteAdder Creative "MIDI Note to Chord" Enhancer VST (Free Windows VST, Open Source Win/Mac/Linux)

NoteAdder basically enhances whatever you play with additional notes. It is neither a chord progression generator nor an AI tool, the control is fully yours, but it does have some optional animation modes and a "granular MIDI" type of sound engine.

See it in action:

This video shows version 2.0, while

• version 3.0 improves the GUI with separate manual / scale mode tabs, save / load preset for manual mode, added cloud animation mode also for manual mode and added different harmony modes (e.g. quartal) for scale mode,
• version 3.1 adds a piano roll with color-coded notes, a note color picker for the visualizer, reset buttons, and an audit mode where the plugin plays sine waves at the generated notes - but the intention of this plugin stays being a MIDI generator only, whose notes you feed into your synth of choice,
• version 3.14 adds MIDI recording and humanizer settings,
• version 3.141 introduces a resizable GUI and
• version 3.1415 adds a new custom mode where for each note you can type in which chord it should consist of, including the option to enter comma separated values like "-2, 5" so pressing this note will also trigger the note 2 semitones below and 5 semitones up (up to 7 additional notes).

What is NoteAdder?

NoteAdder is a MIDI plugin (VST3) that takes the notes you play and adds extra notes around or on top of them, in real time. It does not produce any sound itself (except sine waves in Audit mode for testing). It works as a MIDI processor that sits in front of your synthesizer or sampler. It appears as a synth plugin to make it compatible with MIDI in and out in FL Studio.

You play one note → NoteAdder plays a chord of a scale and complexity of your choice.

You play a chord → NoteAdder plays many chords at once.

You can create lush harmonies from the many different scales and modes, cyclic inversions that bring rhythm into the same chord, or experiment with scale-less chords. Or you can lock yourself to a scale so that accidentally pressing a note outside it simply won't make a sound.

It has two independent ways of doing this: Manual mode, where you define the extra notes yourself as fixed interval offsets, and Scale mode, where it builds diatonic chords automatically from a key and scale you choose.

Setup (in FL Studio)

1. Load NoteAdder as an instrument in a channel rack slot (or inside Patcher). If you want to use it inside Patcher, connect NoteAdder's MIDI out port to your synth's MIDI in port in the Patcher cable view.

2. In NoteAdder's plugin settings, set Output port to 0.

3. Load your target synthesizer in another channel rack slot. Its input port should be default (unset or 0).

4. NoteAdder's MIDI output will now feed into your synth automatically.

Please also refer to the provided PNG for the FL Studio setup.

The Piano Roll Visualiser

A vertical piano roll strip runs along the left side of the plugin at all times. It shows every note currently playing out of NoteAdder in real time, coloured by pitch class (see Note Colours below). You can also click or drag on the piano roll to play notes directly - useful for auditioning chords without a keyboard.

The AUD button (top of the plugin) activates Audit mode, which plays sine waves for all active output notes so you can hear what NoteAdder is generating even without a synth connected.

The Two Modes

At the top right of the plugin you will find two buttons: MANUAL and SCALE. Only one is active at a time.

Manual Mode

Manual mode gives you seven independent note slots. For each slot you can define an interval offset relative to whatever note you play. When a slot is active, that extra note plays alongside your original note every time.

Controls per slot

- Checkbox - enables or disables this slot.

- Semitones - the interval in semitones, relative to the incoming note. Full names are shown: Unison, Minor 2nd, Major 2nd, and so on up to Octave. Negative values go below the played note, positive above.

- Octaves - adds additional octave shifts on top of the semitone value. Range is -7 to +7. Combined total offset is semitones + (octaves x 12).

Example: Semitones = +7 (Perfect 5th), Octaves = +1 → the added note is a Perfect 5th plus one octave above what you played.

Header buttons (Manual mode)

- RND - randomises all seven slots at once, picking musically relevant intervals and enabling roughly half the slots. Useful for quickly finding interesting textures to fine-tune.

- RST - resets all seven slots to disabled with zero offset. One click to start fresh.

- SAVE / LOAD - saves or loads the entire plugin state (both modes, all settings, colours) as a ".nastate" file.

Scale Mode

Scale mode builds chords automatically based on music theory. You choose a key and scale, and NoteAdder figures out the correct chord tones for every note you play within that scale.

Root

The root note of the scale. C, C#, ... through B.

Scale

The scale type. Available options:

Major, Minor, Penta Major, Penta Minor, Lydian, Mixolydian, Dorian, Phrygian, Locrian, Harmonic Minor, Melodic Minor, Lydian Dom., Phrygian Dom., Altered, Whole Tone, Blues.

Add

How many notes to stack on top of your played note (0 to 7). Notes are chosen by stacking diatonic intervals upward from the note you played according to the selected Harmony mode. Notes played outside the selected scale are passed through unchanged unless Discard out-of-scale is active.

Harmony

Controls the interval size used when stacking chord tones. Options run from secundal (stacked 2nds) through tertian (the classical thirds-based stacking), quartal, quintal, sextal, and s