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Review of Scaler 1.5 – chord detection and creative chord progression creator utility (VST/AU/AAX) by PluginBoutique

PluginBoutique have updated Scaler to version 1.5. I’ve previously reviewed version 1.2 and have updated the review to reflect the changes.

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.

It is available in AAX, VST and AU formats as 32 and 64 bit versions from PluginBoutique’s website. It is typically priced at £39.95

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 2000 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, and record or drag the progression into your DAW.

Download and Installation
This is a straightforward process, the file is quite small so download and installation is quick. Registration is similarly straightforward. When you have purchased Scaler it is available to download from the ‘My Products’ section of your account where you will find a keyfile to download. When you lauch Scaler, you register the keyfile and enter your registered email address and you’re good to go.

It’s worth noting that there are two versions, Scaler and ScalerControl. They are essentially the same except ScalerControl is designed for DAWs that use AU plugins that don’t allow you to route midi to other tracks.

It’s also worth checking the website because there are some compatibility issues although these are being fixed as Scaler is updated. For example, in version 1.5 there are reported issues that Maschine 2 and Reason don’t support midi routing and it is suggested that Bluecat Audio Patchwork is used for this.

Using Scaler
Scaler effectively has 3 modes. It can detect chords and identify what key / scale you are playing, you can explore a range of keys and scales and you can create your own chord progressions.

Scaler loads as a midi effect. In Usine Sensomusic Hollyhock 3 you simply need to load Scaler as a patch into a rack and load the VST synth you want to control underneath. You can load the pianoroll between the two to drag and drop the chords / progressions onto.

In MuLab 7 it’s a very similar process, load Scaler into a rack and load the VST synth you want to control underneath. When you audition chords, it will use the selected VST sound. In practice, I find it’s easier to create a rack for Scaler with it’s own track and I export individual chords rather than the whole progression to the Scaler track so that I can copy these onto further tracks and edit as required.

Since I wrote the original review, Scaler has been updated to version 1.5 that brings a number of improvements and bug fixes.

The GUI is clean and well laid out. The top section has the control bar with a display for the input note / chord, help, volume and sound selection, tooltips and embedded guide and global settings. The keyboard underneath acts as an input device and display for notes in a selected scale. Version 1.5 also brings the option to switch between a keyboard and a guitar fretboard to visualise the scale / chord and also options to strum or play the chord as an arpeggio. The bind midi function allows you to play and record one-finger chords.


Beneath this are options to turn on midi detect; the create button allows you to create chords on the keyboard or guitar fretboard and an excellent touch is that you are not limited to standard tuning, there are a number of open tunings available. You then drag the created chord to the progression at the bottom of the screen to save it. Next to these are the chord set selectors that allow you to choose between song type, artist or user set. When you choose a song or artist the chord progression is displayed underneath.

1_5_scale selection

The next section shows detected scales including details of the number of matching notes and chords and mood of the particular scale. This can be expanded to include more details.


Beneath this is the chord selection and progression builder. When you select a song by style or artist, the chord progression is displayed in the top section of the GUI. The detected scales section shows the most appropriate scale and the chords in that particular scale are displayed at the bottom. The diatonic chords are the ‘basic’ chords and chord variations offers a range of different sounds and the voicings options allows you to play the notes in a different order which gives further variation. The display to the right shows the note, it’s relative position in the chosen scale and a couple of chord substitutions.


Often chords will fit more than one scale so if you highlight a different detected scale, the chords that fit are highlighted in blue on the progression shown in the top part of the display and as you scroll down the list and select these different scales you will see that fewer and fewer chords fit into that particular scale.

You can drag chords from the top section into the progression builder as suggested but you can also audition and select alternatives and different voicings from the selection options to fine tune the progression and create interest and variation. You can choose the octave and inversion and then play the progression. Version 1.5 brings undo / redo options and a handy multi-select to drag and drop multiple chords (in any order) to the progression builder. There are also further options with a right-click – edit, substitute, explore scales or generate parallel harmony.

The final stage is to drag the progression or individual chords into your DAW.

I think this is a very useful tool for musicians that don’t know music theory but also for those that do. For those with a limited knowledge, it could be useful to identify what chords you are using and help you sound more musical by choosing chords within a particular key or scale. If you know music theory, it could help you identify substitute chords or create new progressions from styles you might not normally use.

Either way it is a tool to provide inspiration and help you find new ways to be creative. There is a focus on modern music styles with a number of artists and progressions that are difficult to find generally so it’s an excellent tool to help you create new styles of music that you may struggle to do on your own.

I really like how the updates bring new functionality, improved usability and increase the potential use of scaler, for example the guitar fretboard visualisation option is a very welcome addition enhanced by arpeggio and strum options. New chord sets are always welcomed too.

Although Scaler has an excellent set of chord progressions, I’d say that you’ll get much more out of it by experimenting with variations and voicings as these will vastly expand the use of these progressions and add interest and variation.

If you’re looking for a tool that is quick and easy to use and provides inspiration for many modern music styles then Scaler is excellent. Having used Scaler quite a lot since the original review, I’ve found that with a bit of editing, changing octaves and layering you can create basslines and melodies fairly easily, it obviously depends on the style that you’re producing but Scaler can help create anything from a chord progression to a whole composition. It has kick started and been the inspiration for a large number of songs.

The ‘arbitrary lines’ album embedded at the top of the review was created using Scaler to create chord progressions that have been edited for bass notes, note lengths changed etc and then layered using the British Drama Toolkit by Spitfire Audio. I’ve also used a couple of instances of Polygon by Glitchmachines and a couple of recordings from a short-wave radio. Eventide effects were used extensively.

This is an ambient / neo-classical album, the chord progressions have been used in a very different style from that suggested by Scaler but it shows the versatility of Scaler and how a seemingly simple chord progression can be used as a basis for a whole composition with some further editing in your DAW.