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Chord Generator Plugin by Plugin Boutique
Scaler Scaler
Scaler by Plugin Boutique is a Virtual Instrument and a Virtual Effect Audio Plugin and a Standalone Application for macOS and Windows. It functions as a VST Plugin, an Audio Units Plugin, an AAX Plugin and a Standalone Application.
System Requirements
Windows 7 and later (64-bit compatible)
System Requirements
OS X 10.7 and later (64-bit compatible)
Stand-Alone Utility / Application
Copy Protection
Key File
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107 KVR members have added Scaler to 13 My KVR groups 133 times.
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The Creative Chord Composer

Scaler is a unique and inspirational MIDI effect that makes finding chords and progressions intuitive and fun. With note detection, scale selection and chord suggestions, Scaler is a comprehensive but easy-to-use toolbox that will help anyone make better music.

A first of its kind, Scaler can determine what key and scale you're in and suggest chords that match your music, or it can inspire a tune from scratch by providing a set of initial chords in an unexplored key. With the onboard bank of over 2,000 scales and modes including genre and artist presets, there's more than enough to keep the juices flowing.

Once you've determined a scale, Scaler lays out basic diatonic chords for you to audition, and lets you take things further with dozens of chord variations and voicings to try out. Theory buffs can also get an insight into each chord's harmonic function.

Ready to put together a progression? Simply drag and drop chords into Scaler's sequencer, change up octaves and inversions, edit the voicing, and record or drag the progression into your DAW:


  • Discover your music's key and explore alternative scales and chord sets.
  • Choose from hundreds of keys, and get the harmonic flavours of pro artists.
  • Easily audition chords and find alternative voicings and common substitutions.
  • Quickly build intelligent progressions by dragging chords into Scaler's chord sequencer.
  • Drag chords and progressions from anywhere in the plugin out to your DAW.


  • Discover your track's current scale with MIDI keyboard or piano roll note detection.
  • Get an insight into the emotional content of matching scales.
  • 12 keys across 23 scales and modes giving you a total of 276 options to choose from.
  • 12 unique voicing types giving you a potential of over 2,000 Scales and modes.
  • Over 100 artist chord sets from the likes of Carl Cox, MJ Cole, The Temper Trap, Mitekiss, CeCe Rogers and Mike Huckaby.
  • Over 100 genre and mood-based chord sets such as Chill, Drum & Bass, Jazz, Cinematic, EDM...
  • Check how closely a given scale matches your detected input.


  • Keep an eye on notes and chords going through Scaler with real-time visual feedback.
  • Visualise the chosen scale as highlighted notes on Scaler's piano keyboard or guitar fretboard.
  • Audition chords from your chosen scale with a choice of eight internal sounds.
  • Play and record one-finger chords using Scaler's Bind MIDI function.
  • Use the arpeggio or strum features to perform in real time and synced to your DAW.
  • Assign any VST / AU instrument to Scaler to control your favourite synths.


  • See the basic diatonic chords that can be built from your chosen scale.
  • Browse Chord Variations for each note to get suspended chords, extended chords, dominant sevenths and jazz chords.
  • Quickly get a sense of each chord's harmonic function in progressions.
  • Discover chord substitutions that lend variety to your progressions.
  • Experiment with different chord voicings to spread notes across the keyboard.
  • Mix and match from hundreds of artist and genre-based chord sets.


  • Drag and drop chords from your palette into Scaler's Progression Builder.
  • Edit, transpose and invert chords for even more voicing styles.
  • Audition your progressions and make changes with drag-and-drop.
  • Save your own chord sets to the preset bank for later use.
  • Export MIDI to your DAW simply by dragging and dropping.

How Does It Work?

Scaler is a plugin instrument capable of outputting MIDI as well as audio. With regard to the latter, a piano, guitars, strings and several sampled synth sounds are built in for scratch work, so you can quickly get a chord progression together for export as a MIDI file entirely within it.

Obviously, though, the idea is to trigger other instruments via Scaler, and how this is set up depends on the host DAW. For VST hosts, Scaler loads as an instrument plugin onto a MIDI track, the output of which is sent to a second track (hosting the target instrument) using the DAW's routing system.

For Audio Unit hosts (ie, Logic Pro), the included ScalerControl MIDI effect plugin is loaded up instead. This is identical to the regular Scaler, but sits in front of the target instrument on the same track, outputting MIDI directly to it. It's certainly the more elegant of the two approaches, although it only captures the raw triggering notes to the track, not the chords output by the plugin.

{See video at top of page}

New Features in Version 1.5:

  • Fretboard Display: Designed in conjunction with world-leading guitarist Joseph Greer from the 'The Temper Trap'.
  • Arpeggio and Strum performers: Fully fledged arpeggio and strum features to greatly enhance live performance.
  • Scale Lock: Effortlessly create melodies locked to the scale of your currently selected chord set.
  • Chord Editing: Edit existing chords or create new chords from scratch using the keyboard or fretboard display.
  • Parallel Harmony: Generate instant parallel harmony by selecting your favourite chord and laying it out across the keyboard.
  • Relative Chord Finder: Transpose chords by any diatonic or non-diatonic interval whilst retaining their shape.
  • Scale Explorer: Explore scales that contain the currently selected chord - great for modulation.
  • Undo Redo: Undo or redo chord and voicing edits in your progression builder.
  • Multi-Select: Select multiple chords in any order to drag and drop to the progression builder.
  • 21 New Genre and Artist Based ChordSets: The Temper Trap, Mitekiss, Royalston, Joseph Greer, deliBass, Matt Ridgeway, and new Cinematic chord set.
  • 4 New Internal Sounds: Electric Guitar, String Ensemble, Acoustic Guitar, Harmonic Guitar.

New Features in Version 1.2:

  • Humanise Velocities: the velocity of each note within chords is randomised to provide a more natural playing style.
  • MIDI Export Length: select length of MIDI notes for export and drag and drop.
  • Improved Progression Builder: Now handles up to 16 chords & chord progression is now played at DAW tempo.
  • 21 New ChordSets: Classical (8), K-Pop / J-Pop (6), Neo Soul (6).
  • 11 New Scales: Lydian augmented scale, Acoustic scale, Major locrian scale, Ukrainian dorian scale, Hungarian gipsy scale, Melodic minor scale (asc), Half-diminished scale, Phrygian dominant scale, Persian scale, Neapolitan major scale, Neapolitan minor scale.

New Features in Version 1.1:

  • Change Bound Octave: Choose which octave to bind to trigger chords directly from the bind MIDI button.
  • Split Keyboard: Ability to play second line when MIDI bind is active.
  • Accompaniment: You can now play a melody line or bass line along the chords you trigger through Scaler.
  • MIDI CC Through: Scaler now allows MIDI CC message pass through for better control of your external instruments.
  • Trigger Multiple Chords Simultaneously: Trigger multiple chords at once and create complex harmony by combining different voicings.
  • 10 New ChordSets: EDM (5), Drum & Bass (5).

System Requirements


  • OS X 10.7 and later (64-bit compatible only).


  • AAX.
  • Audio Units (AU).
  • VST.


  • Windows 7 and later (32 and 64-bit compatible).


  • AAX.
  • VST.

Scaler 1.5 Compatibility.


  • FL Studio 12 - OK.
  • FL Studio 20 - OK (MIDI routing available from VST2 only).
  • Cubase 9.5 - OK.
  • ProTools 12.8 - OK.
  • Studio One 3 - OK.
  • Studio One 4 - OK.
  • Ableton Live 9 - OK.
  • Ableton Live 10 - OK.
  • Reaper - OK.
  • Bitwig Studio 2 - OK.
  • Maschine 2 - OK - No MIDI Routing: Use Blue Cat Audio Patchwork for MIDI Routing.
  • Reason - OK - No MIDI Routing: Use Blue Cat Audio Patchwork for MIDI Routing.


  • Cubase 9.5 - OK.
  • ProTools 12.8 - OK.
  • FL Studio 2 - OK (VST, not VST3).
  • FL Studio 20 - OK (MIDI routing available from VST2 only).
  • Studio One 3 - OK.
  • Studio One 4 - OK.
  • Ableton Live 9 - OK.
  • Ableton Live 10 - OK.
  • Logic Pro X - OK.
  • Reaper - OK.
  • Bitwig Studio 2 - OK.
  • Maschine 2 - OK - No MIDI Routing: Use Blue Cat Audio Patchwork for MIDI Routing.
  • Reason - OK - No MIDI Routing: Use Blue Cat Audio Patchwork for MIDI Routing.

Latest User Reviews

Average user rating of 4.50 from 2 reviews

Reviewed By HGC
December 11, 2020

This plugin is great if you are a beginner in music theory, or want an easy way to implement more complex chords into your production. Great learning tool.

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Reviewed By mtelesha
August 23, 2018

I have gone from a skeptical person of all the "skip music theory cheating apps" to finding Scaler makes me a better musician. Main use is to see what chord I am playing and make sure it actually is an 11th with a 5b. I also like lining up my chord progressions and then playing around with different fill chords. Sure I do 90% of my playing by well playing, but when I am digging in with Scaler I am expanding what I am playing on the keyboard due to Scaler.

Also makes it super easy to build chords in a DAW quickly. I record 2 tracks with one being the raw MIDI from my controller and the 2nd track is Scaler playing chords to the track. Remind me when I would record bass direct and re-map the bass into an amp later.

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