Triad Explorer

About Triad Explorer

This application helps you master the fretboard by focusing on musical triads. While the core idea is to train your understanding of three-note chords, the app expands your learning to a true understanding of the fretboard and the harmonic space. You can select a key, a specific triad, and even add individual notes or suggested scales to visualize and hear different harmonic possibilities. The dynamic fretboard shows you exactly where each note lies, helping you to connect the abstract concepts of harmony with their physical locations on the guitar.

In building the app my focus was on providing a logical way to learn triads per key, and to build progressions from the triads, rather than just rote learning a bunch of shapes and positilons. Using the key-based approach provides (IMO!) for a deeper understanding of harmonic relationships, and promotes better voice-leading. Thus, for now, the focus is on major, minor and diminished triads that fit each diatonic key. This will probably be expanded in future to include augmented, sus, and open triads (my ultimate goal is to go 'full jazz').

How to Use

Key & Chord Selection: First, open the Options (☰) menu (top right) to select a Tuning. Then, select a musical Key from the main controls. The Chords buttons will automatically update to show the diatonic chords for that key. Hover over a chord to see its Roman numeral.
Chord Selection: Click any Chord button to see its notes displayed on the fretboard.
Add Intervals: Use the Intervals buttons to add extra notes to the selected chord. These buttons are context-aware; for example, if you select a diminished chord (which has a diminished 5th), the 'd5' button will change to 'P5', allowing you to add a Perfect 5th.
Fretboard Options: Click the Options (☰) button to open the settings menu. Here you can change your Tuning, the number of Frets shown, the player View (Righty/Lefty), and toggle the note Colours (Polychrome/Monochrome).
Metronome: Use the Metronome controls to practice in time. Click the ► button to start or stop the click. The button will flash in time with the beat. Click the ☰ button next to it to open the settings panel, where you can adjust tempo, time signature, sound, and volume.
Note/Interval Display: Click anywhere on the coloured legend below the fretboard to switch the note display between note names and interval names. A tooltip will appear on hover.
Suggested Scales: The Suggested Scales list provides ideas for improvisation based on your selected notes. Clicking a scale displays all its notes on the fretboard.
Slide Suggestions: Once a scale is selected, the Slides menu will appear. Click the button to activate slide suggestions (the label will be underlined). You can then choose the slide direction (UP/DOWN) and a genre (Blues, Rock, Country, or Jazz).
Mute Strings: Click on any string's name (e.g., E, A, D) to the left of the fretboard to toggle its notes on and off.

Musical Rules & Design Rationale

Programmatic Music Theory

The application's musical intelligence is driven by a programmatic engine that generates scales and chords on the fly. Instead of relying on a fixed list of pre-defined keys, the app uses interval formulas (e.g., Major Scale: R-2-3-4-5-6-7) to construct any scale from any root note. This ensures accuracy and makes the system highly expandable.

Diatonic Harmony & Note Spelling

When you select a key, the app generates the seven diatonic chords by applying the correct triad quality (major, minor, etc.) to each degree of the chosen scale. The engine also ensures all notes are displayed with their proper diatonic spelling (e.g., using `Bb` in the key of F Major, not `A#`) by considering the harmonic context.

Context-Aware Scale Suggestions

The 'Suggested Scales' feature is more than a simple filter. It analyzes the selected chord and its harmonic function to provide musically intelligent recommendations. It prioritizes scales that are conventionally paired with the active chord (e.g., suggesting Mixolydian for a dominant 7th chord) and also identifies "bluesy" or "best-fit" options that, while not a perfect match, are common in modern improvisation.

Chord-Sensitive Slide Suggestions

The slide suggestions are generated by a dynamic rulebook that is sensitive to the currently selected chord. The engine prioritizes slides that target the notes of the active chord (the root, 3rd, and 5th), resulting in melodic lines that are more harmonically coherent and musically pleasing. The genre selection (Blues, Rock, etc.) further refines the suggestions to fit the stylistic conventions of that genre.

'Dave's Scale'

A special mention for 'Dave's scale', a hybrid minor blues scale used by Dave Simpson. See the discussion by the Maestro himself in this video: Dave Simpson's Hybrid Blues Scale.

Two version of the scale are provided, Dave's Scale OG, which exactly replicates the Scale developed by Dave himself, and Dave's Scale +, which adds extra blue notes in both minor and major versions.

At its heart, Dave's Scale OG is a hybrid or "supercharged" version of the Minor Blues scale. It takes a familiar blues foundation and adds extra notes to provide more melodic and expressive possibilities.

The scale is built from the following intervals relative to its root:
Root, Major 2nd, Minor 3rd, Perfect 4th, Diminished 5th, Perfect 5th, Minor 6th, Minor 7th

What Makes It Different?

To understand what makes this scale special, it's best to see how it's constructed:

It starts with the Minor Pentatonic scale: (R, m3, P4, P5, m7).
It adds the Diminished 5th (the classic "Blue note") to become the Minor Blues scale. In the OG version, Dave only uses Blue notes on the A and G strings.
Finally, it adds two extra "flavor notes": the Major 2nd and the Minor 6th.

These two additions are the key. The Major 2nd provides a smooth melodic step between the root and the minor third, giving it a brighter, more "Dorian" mode quality. The Minor 6th adds a touch of melancholy, characteristic of the Natural Minor scale, offering another color to the melodic palette.

Using Dave's Scale

Over Minor Chords (Its Natural Habitat)

When used over a minor chord, the scale feels right at home. The two main flavor notes serve distinct musical purposes:

The Major 2nd adds a lyrical, melodic quality, perfect for connecting phrases and avoiding the "boxy" sound of the pure pentatonic scale.
The Minor 6th adds a soulful, sometimes somber, character. It works beautifully as a passing tone between the minor 7th and the perfect 5th.

Over Major & 7th Chords (The "Secret Sauce")

This is where the scale's magic really lies. When you select a major chord (e.g., G Major), the app suggests playing the Dave's Scale of its relative minor (e.g., E Dave's Scale).

This works because the notes of E Dave's Scale, when played against a G Major chord, create the signature sound of the blues. Let's analyze the intervals:

G Major Chord Tones: G (Root), B (Major 3rd), D (Perfect 5th)
E Dave's Scale Notes: E, F♯, G, A, B♭, B, C, D
Combined Sound: Playing these scale notes over the G chord gives you the G Major triad notes (G, B, D) plus other rich tones like the Major 2nd (A), Perfect 4th (C), and Major 6th (E). Most importantly, it gives you the B♭, which functions as the Minor 3rd of G.

Which Blue Note is "Bluesier"?

When playing over a G Major chord, for example, the app suggests using E Dave's Scale. This scale contains the note B♭. So why does that B♭ sound so "bluesy" over a G Major chord?

The Minor 3rd Tension: To our ears, that B♭ acts like the minor 3rd of G. The clash between this "sad" minor 3rd (B♭) and the "happy" major 3rd of the G chord (B) is the quintessential sound of the blues. It's the note that gives blues its signature soulful, melancholic flavor over a major chord.
What about the "other" blue note?: The technical "blue note" for G is C♯ (the diminished 5th). This note creates a different, more "twangy" tension often heard in country or rockabilly. While also useful, the B♭ provides the foundational, defining sound of traditional blues.

By using the relative minor's scale, the app helps you tap into that authentic blues flavor over any major chord.

The Special Rule: Filtering the Minor 6th

To keep the scale sounding as clean as possible over a major chord, the app applies one final, subtle rule:

The Minor 6th is Hidden: When using this trick, the app hides the note that is a minor 6th above the root of the major chord. For example, when a G major chord is selected, the note E♭ is hidden. This note isn't part of the suggested scale and can sound dissonant, so it's removed to keep things sounding smooth.

Of course, you can always add or remove any intervals you like to find your own 'special sauce'.

Dave runs an online community here. If you really want to master the guitar, forget the rest.