Chord Lab
Learn how chords are built on the piano.
Root
Family
Quality
Keyboard: choose quality with Q–T, inversion with 0–3, then play a root on Z–M. Space repeats; A hears tones separately.
C major
Root positionC is in the bass (root). Root and bass are different concepts.
Which note is the third of C major?
Use the formula and colored chord tones above.
How the notations fit together
Music uses several labels because each one answers a different question. For the same C-major chord with E in the bass:
- Chord symbol
- C/E
- What chord do I play? C major, with E as the lowest note. Common on lead sheets.
- Roman numeral + figures
- I⁶
- What is its job in this key? The tonic chord in first inversion in C major.
- Figured bass
- 6
- What intervals sit above the bass? This identifies a first-inversion triad.
- Bass scale degree
- 3̂
- Which note of the C-major scale is in the bass? E is scale degree 3.
- Chord degrees
- 1 · 3 · 5
- How is the chord built from its own root? C, E, and G.
C or Cmaj means a C-major triad. Cmaj7 is different: it adds B as the major seventh.
The Big 18
The lecture’s core vocabulary, arranged by the scale degree in the bass. Select a chord to see its chord symbol, Roman numeral with figured bass, spelling, and keyboard shape above.
1̂in bass
2̂in bass
3̂in bass
4̂in bass
5̂in bass
6̂in bass
7̂in bass
Example: C is I in C major; C/E is I⁶; and C/G is I⁶⁄₄.