Ultralocrian bb3 Mode on Guitar: Notes, Chords & Examples

Ultralocrian ♭♭3 is an extremely tense, unstable, and dissonant mode. It is not a “pretty” or naturally resolved sound. It feels dark, compressed, crooked, and almost hostile.

For guitarists, this mode works best when you want:

Extreme metal tension
Fusion “outside” lines
Progressive rock weirdness
Horror or sci-fi soundtrack colors
Unstable riffs over a pedal tone
Diminished/altered dominant-style drama

This is an advanced synthetic mode, so it does not behave like Dorian, Phrygian, or Mixolydian. It has no perfect fifth, no normal third, and no normal minor seventh. That makes it hard to harmonize traditionally, but very powerful for riffs, modal vamps, and outside improvisation.

Ultralocrian ♭♭3 is the 7th mode of Neapolitan Minor.

How does it sound?

Before anything else, let’s hear how it sounds. This can best be done by playing a chord from the mode, and playing the notes of the mode arpeggiated on top of it. This is the best and quickest way to determine the feel of a mode.

This can be quickly done using SLModes, a software dedicated to the music modes, and the following sound was generated by it:

Formula

The interval formula for Ultralocrian ♭♭3 is:

1 b2 ♭♭3 bb4 b5 b6 bb7

In interval names:

P1 m2 d3 d4 d5 m6 d7

Compared to a normal major scale, almost everything is lowered or altered. The two most unusual tones are:

♭♭3 — a diminished third, enharmonically the same pitch as a major second
bb4 — a diminished fourth, enharmonically the same pitch as a major third

That enharmonic confusion is part of the sound. On the fretboard, some notes may look familiar, but their modal function is much stranger.

Notes in C

C Ultralocrian ♭♭3 contains:

C Db Ebb Fb Gb Ab Bbb

Enharmonically, this sounds like:

C Db D E Gb Ab A

For guitar, the enharmonic version is easier to visualize. But theoretically, the correct spelling is:

C = 1
Db = b2
Ebb = ♭♭3
Fb = bb4
Gb = b5
Ab = b6
Bbb = bb7

That spelling matters because it shows the actual structure of the mode.

A Chord That Defines the Mode

A practical tonic-rooted chord for C Ultralocrian ♭♭3 is:

C+

Chord spelling: C E G#

These pitches occur in the mode through enharmonic equivalence:

C — the root.
E — enharmonic with Fb, the lowered fourth.
G# — enharmonic with Ab, the lowered sixth.

The mode’s theoretical notes are:

C Db Ebb Fb Gb Ab Bbb

C+ supplies an unstable augmented foundation, but it does not contain the mode’s unusual diminished third, Ebb.

To reveal the complete modal character, emphasize Db, Ebb, Gb, and Bbb in melodic phrases. On guitar, Ebb sounds like D and Bbb sounds like A.

Chord Progression (Example)

Because C Ultralocrian ♭♭3 is so unstable, these progressions work best as modal riffs or vamps rather than traditional functional harmony.

Chords in C:

C+ – Dbm – C+ – Gbm

Chord	Notes
C+	C E G#
Dbm	Db Fb Ab
C+	C E G#
Gbm	Gb Bbb Db

Every pitch belongs to the mode, allowing E for Fb and G# for Ab.

The move to Dbm introduces the lowered second while retaining two pitches from C+ enharmonically. Gbm adds Gb and Bbb, expanding the darker side of the collection.

Return strongly to C+, and feature Ebb in the melody so the doubly lowered third remains audible.

Mood: Unstable, compressed, and otherworldly.

This works well for progressive metal riffs, horror scoring, or fusion sections that need a sudden “outside” turn.

Guitar Fretboard Shape

Here’s the mode mapped across the full fretboard, generated with my software SLModes.

The diagram shows every occurrence of the mode across the neck:

🟢 Green dots = the root note, your anchor points
🟠 Orange dots = the rest of the scale tones

Why Guitarists Love This Mode

C Ultralocrian ♭♭3 sounds tense, warped, and unstable. It does not give you easy resolution. That makes it perfect when you want to avoid predictable minor-scale darkness.

It is darker than Phrygian, more unstable than Locrian, and more dissonant than most altered dominant sounds.

Genres Where It Works Well

C Ultralocrian ♭♭3 can work in:

Progressive metal
Technical death metal
Fusion
Avant-garde jazz-rock
Horror scoring
Dark ambient guitar music
Experimental songwriting
Cinematic home production

It is especially useful when ordinary minor, harmonic minor, or diminished sounds feel too familiar.

Tips for Practicing

To practice a mode effectively, you only need two things:

An instrument to play the mode (your guitar is ready to go!)
A backing track that provides a harmonic context

The fretboard diagram above already show you where the notes are. The remaining piece is choosing an appropriate backing track to improvise over.

Practice with a drone

The simplest option is a single C drone.

You can create one using:

A looper pedal
A synth drone
A sustained bass note in your DAW
An open C tuning
Or any other source of a continuous C note

Because the accompaniment consists of only a single note, you are responsible for highlighting the intervals that define the mode. The more intentionally you emphasize its characteristic tones, the more clearly the modal sound will emerge.

Create modal vamps with SLModes

While a drone is an excellent way to hear a mode in isolation, a modal vamp often provides a more musical and rewarding practice experience.

A well-designed backing track naturally emphasizes the mode’s characteristic intervals, allowing you to focus on phrasing, melody, and expression instead of constantly trying to establish the modal sound yourself. As a result, improvising in the character of the mode often feels more intuitive.

There are many ways to build modal backing tracks, but SLModes can generate them for you in just a few clicks. For example:

Arpeggiated backing tracks — a repeating pattern that outlines every note of the mode.
Chord vamps — progressions built from chords that best reinforce the mode’s unique character.

This video shows you an example: