Pluginboutique’s Scaler is a MIDI utility plugin which, to be blunt, understands the music theory of chord progressions so you don’t have to. Is that controversial? Is that cheating?

Read on to hear our thoughts about this and enter the giveaway at the bottom of this page for a chance to win a FREE copy of Pluginboutique Scaler. Good luck!

The Practice Of Theory

Let’s start with what music theory is. It’s not a set of rules. Arnold Schoenberg’s seminal Harmonielehre keeps repeating that every “rule” will be broken in a later chapter when the student is more advanced. Rather than a set of rules, music theory is an attempt to understand what sounded good to other people in the past, and why it sounded good to them. That is, of course, enormously helpful in understanding why music that sounds good to you sounds that way to you.

So, tonal harmony textbooks attempt to explain why things that sounded nice to composers from Haydn to Wagner sounded good to them. Jazz theory tries to explain why things sounded good to XX century jazz musicians, from Dixieland to free jazz.

Scaler’s focus is a broad range of popular music of the last few decades – anything from EDM to country. If you’ve played or analyzed more than a little bit of this music, you quickly realize that classical theory sort of applies, but not really. Four-part harmony doesn’t really exist, and voice leading is mostly ignored, with plenty of parallel motion. Cadences from the dominant chord to the tonic are often avoided as old-fashioned, obvious, and kind of cheesy. Even seventh chords are rare in many styles. I developed a pretty good grasp of what applies and what doesn’t by learning, quite literally, hundreds of covers in styles ranging from 60s rock to current reggaeton, but this took many years.

Scaler doesn’t try to explain things or educate the user, but rather give the user a broad range of possibilities for creating chord progressions. In a way, it delivers the results of theoretical analysis on a silver platter.

The Practice In Practice

So, how does Scaler actually achieve this? First, the plugin detects chords and scales – play some notes or feed MIDI signal to it and Scaler will tell you what chord these add up to. It does this reasonably well – play A, B and C in a cluster next to each other, and it will not detect them as a chord. Move the B up an octave, though, and it’ll detect the chord as an Am9 – sure, that “should” also contain an E, but non-altered fifths are often optional in real life.

I know many skilled, successful songwriters who could really use this function to tell them what chords their songs have. I’ve dealt with at least two who’d play some notes on piano or guitar without even knowing what those notes were, and keep trying variations on that until they found some things that sounded good to them. Those chords needed to be transcribed by ear or eyeball for other musicians. While Scaler won’t necessarily help the guitarist, for the pianist it would make this job as quick and convenient as possible.

The core functionality of Scaler, though, is not chord detection but showing what chords can be created from the detected or selected scale. This includes the seven diatonic triads in each chord, and variations – chords with added sevenths, ninths etc, suspended chords, and also (importantly) chords with a missing third (in other words, guitar power chords), and triads with the fifth left out, which are very common in more electronic genres. There’s no room for chords including out of scale notes, or even for the melodic minor scale which can use either minor or major sixths, which is fine – those are very rarely used in popular genres today. If needed, they can be “borrowed” from another scale, by switching to that scale, grabbing a chord and then switching the scale back to the main scale of the song. That’s actually an accurate reflection of how such chords are often used in the real world.

The chords can then be dragged into the chord slots, octaves and inversions selected (though for genres like R&B it’d be nice to have some choice of clearly labeled typical voicings for piano, horn sections, and string sections). Once the progression sounds “right,” the chords can be exported to the DAW for use in a song. Do keep in mind that Scaler is not a full-blown chord sequencer, but rather a chord auditioning tool.

Scaler can do jazz chords, but it doesn’t take into account borrowed chords, secondary dominants, etc. It could be used in composing “real” jazz, by switching scales when a chord needs to be borrowed from another scale. However, more importantly, the user still has to understand what scale to borrow from and when. Also, the role of each chord in the progression needs to be figured out – Scaler will not do that for you. So, if you want to compose jazz, you are going to have to understand the theory the old-fashioned way. However, for adding some jazzy chords to, say, a deep house track which will add the right flavor without making a mess of the harmony, this is perfect.

One important aspect of this is that Scaler follows the common practice of creating chord progressions in pop music these days. The progressions are, according to classical theory, not so much progressions which logically progress in a specific direction, but rather chord successions, where chords follow one another without any particular rules as to what is expected to follow what. Also, unlike all those exercises in harmonizing a melody, in pop these days the chords usually come first, and melodies are added to them.

Scaler also includes a library of chord progressions for certain moods, genres, and artists. The chord library is tremendously useful – you can see what sounded good to others in the past, and learn from that. You can quickly see what kinds of chords are common in a genre – whether it’s mainly triads, or if big jazz chords show up. It’s also convenient to see which genres use chords which are not found in the scale, and what these borrowed chords might be – they are found in many progressions and are easily visible, as they have grey rather than blue boxes around them. These show up in most jazz progressions, some rock progressions, and no EDM progressions, as I would expect. You can also directly use those chord progressions for your songs. I could write an entire lengthy explanation of why there’s nothing wrong with using common progressions, but that’s not the point of this review, so instead, I’ll just say this – under US law, chord progressions normally cannot be copyrighted.

The Target Audience

So, is Pluginboutique Scaler a tool for people who don’t understand the music theory and don’t want to learn? Sure, there’s some truth to that, and there’s nothing wrong with it. Like I’ve said above, I know people who are able to write good songs without even knowing the names of the notes they’re playing. Their songs still very much follow the same basic rules of music theory that Scaler follows, regardless of whether the composer was aware of them or not. For someone like that, this tool can be helpful for getting out of a rut, jump-starting a new song, or transcribing the chords for other musicians. Musicians who understand theory can also use Scaler for similar rut-evading purposes, as even if you know all these chords and their sonorities by heart, picking them out of a list still gets you out of the habits you fall into when playing these chords with your fingers.

Another good potential use of Scaler is by people who understand music theory to some degree but want to write music that’s a little beyond their current understanding or in an unfamiliar genre. This tool makes it easy to see what chords are available within a given scale, hear what they sound like, and assemble something coherent out of them. The example I gave above mentioning jazzy chords in a deep house track comes to mind, but someone who has learned the basics of classical theory and is not sure how it applies to pop could also benefit a lot from this tool – it delivers the important components of chord progressions as they are actually used, and ignores all the mostly-irrelevant things such as cadences and voice leading.

Final Cadence

Scaler is so efficient that some people will feel dirty using it, as if they’re cheating by doing so. Others will want to convince themselves that they don’t need it because they know all these things already (and I have enough self-awareness to know I land in this category). But if you can get over that, it’s a great tool for jump-starting the creative process as well as for understanding how chords work in recent popular music.

More info: Pluginboutique Scaler ($49)

The Giveaway

Pluginboutique is kindly giving away one free copy of Scaler to one lucky BPB reader! They will also be sponsoring our NAMM 2018 coverage. Many thanks to Pluginboutique for their continued support!

To enter the giveaway, submit your name and email address in the form below. You will be subscribed to BPB’s mailing list, with the option to unsubscribe at any time. You can further increase your chances of winning by completing the bonus entries (such as subscribing to our YouTube channel, following us on Twitter, etc.).

The winner will be announced on this page on Friday, January 19th. We will also notify the winner via email, so please double-check your email address for typos when entering the giveaway. Good luck everyone and thanks for reading BPB!

Congratulations to our reader Shunto K! :)

Plugiboutique Scaler

Scaler Review


Scaler is so efficient that some people will feel dirty using it, as if they're cheating by doing so.

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This article was written by two or more BPB staff members.


  1. I’m indecisive which one to get between Scaler and Captain Chords… Would be great to hear what you think of Captain Chords and how you’d compare them side by side.

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