Chord Structure

A triad is two thirds stacked on top of each other. Because a third is either major or minor, only four combinations exist, and those four account for every major, minor, diminished, and augmented triad. This lesson also shows how taking every other note of a scale produces chords for free.

Tools used in this lesson: Chord Finder

Which note you put at the bottom changes how a chord behaves. The pitches stay the same while the stability and the shape of the bass line change, and figured bass is the notation that records it. This lesson pins down exactly what the numbers 6 and 6-4 are counting.

Tools used in this lesson: Inversion & Figured Bass Trainer / Chord Finder

Stack one more third on a triad and you have a seventh chord. Adding the seventh guarantees a dissonance inside the chord, so the chord itself starts demanding resolution. This lesson covers the five types in practical use and why the dominant seventh is the important one.

Tools used in this lesson: Chord Finder

Roman numerals name chords by scale degree instead of by letter, so one description covers every key at once. This lesson sorts out upper and lower case, the added inversion figures, and the conventions that apply specifically in minor keys.

Tools used in this lesson: Roman Numeral Analysis Trainer / Diatonic Chord Reference

Chord symbols record absolute pitches; Roman numerals record roles inside a key. Neither is superior - they store different information. Being able to move between them is what makes popular and classical theory a single continuous subject rather than two.

Tools used in this lesson: Chord Finder / Chord Progression Analyzer