Triads, 7th Chords, Lead-sheet Symbols
Dr. B Music Theory

Triad

The most common chords are triad. It's a 3 notes chord.

triad = tertial types/sonorities:

• major triad: (M3 P5) C E G
• augmented triad: (M3 A5) C E G#
• minor triad: (m3 P5) C Eb G
• diminished triad: (m3 d5) C Eb Gb

Lead sheet symbols

• A (+) for augmented
• M for major
• m for minor
• d (°) for diminished

The 1 is called the root, the 3 is called the 3rd and the 5 is called the 5th.

The root of the chord is always write in uppercase letter. For exemple:

• Bb+ is B flat augmented triad.
• Bb is B flat major triad.
• Bb- or Bbm is B flat minor triad.
• Bb° is B flat diminished triad.

Seventh Chord

Using 4 notes. The interval between root and top note is a seven.

• MM7 = Major triad with Major seven / Major seven chord, notation C^MA7, C^MAJ7, C^△7.
• Mm7 = Major triad with Minor seven / Major minor seven chord (dominant 7), notation C⁷.
• mm7 = Minor triad with Minor seven / Minor seven chord, notation C-7, Cm⁷.
• dm7 = Diminished triad with Minor seven / Half diminished seven chord (Minor 7b5), notation C^Ø7, C-7^b5.
• dd7 = Diminished triad with Diminished seven / Diminished seven chord (fully diminished), notation C^°7.

Previous Lesson Main Page Notations Next Lesson

Web pages built using dev.music libraries.