How Orphere Assigns Roman Numerals: Automatic Harmonic Analysis in the Studio
When you pair a chord with a scale in Orphere, the studio automatically tells you the chord’s roman numeral, its harmonic function, and whether it’s diatonic. You don’t need to work it out yourself. This post explains what that analysis means and how it works.
What is a roman numeral?
A roman numeral describes a chord’s position and quality relative to a scale. In C major, the chord built on the first degree (C) is I, the chord on the second degree (D) is ii, and the chord on the fifth degree (G) is V. Uppercase numerals indicate major quality, lowercase indicate minor.
The numeral tells you more than just “which note is the root.” It tells you the chord’s function within the key: tonic (I), dominant (V), subdominant (IV), and so on. These functions describe the role the chord plays in creating tension, resolution, and forward motion.
How Orphere determines the numeral
When you load a scale and a chord into a slot, Orphere checks two things:
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Is the chord diatonic? Every note in the chord must belong to the scale. If any chord tone falls outside the scale’s pitch classes, the chord is not diatonic.
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Where is the root? If the chord is diatonic, Orphere finds the chord’s root note within the scale and looks up which degree it sits on. That degree gives the roman numeral.
The result is a numeral name that replaces the root note with the numeral. For example, if your scale is C dorian and your chord is G min7, Orphere finds that G is the 5th degree of C dorian, so the chord is labelled V min7.
Functions
Each degree carries a traditional harmonic function:
| Degree | Numeral | Function |
|---|---|---|
| 1 | I | Tonic |
| 2 | II | Supertonic |
| 3 | III | Mediant |
| 4 | IV | Subdominant |
| 5 | V | Dominant |
| 6 | VI | Submediant |
| 7 | VII | Subtonic |
These functions are what drive cadence detection in region moves. An authentic cadence (V to I) works because the dominant resolves to the tonic. A deceptive cadence (V to VI) works because the expected resolution is subverted. Orphere uses these functions automatically when analysing moves between regions.
When a chord isn’t diatonic
If any chord tone falls outside the scale, Orphere marks the chord as chromatic (CHR). This doesn’t mean the chord is wrong or unusable, it just means it can’t be expressed as a simple roman numeral within that scale.
Chromatic chords are common in practice: borrowed chords, secondary dominants, and altered chords all contain notes outside the current scale. When Orphere marks a chord as CHR, it also shows you the non-chord tones, the scale notes that aren’t part of the chord, giving you a clear picture of how the chord relates to the surrounding pitch material.
Why it matters
Roman numeral analysis connects individual chords to the broader harmonic context. Without it, a chord is just a collection of notes. With it, you can see that your chord is the dominant, or the mediant, or a chromatic substitution.
In the studio, this analysis happens instantly for every region you build. When you’re constructing a progression, you can see the roman numerals across all your regions and track how the harmonic functions flow from one to the next.