Triads
Three-note chords — the building blocks of harmony
A triad is a three-note chord, built by stacking two thirds above the root. Its type depends on the size of each third.
The two most common triads, major and minor, make up roughly 80% of the chords in popular music and are the focus of NoSheet's curriculum. They differ by a single semitone: the third is either major (4 semitones, bright) or minor (3 semitones, dark). Both contain a perfect 5th, which gives them stability. Remarkably, they maximize both consonance and voice-leading efficiency while arising naturally from the major modes — take any note of the scale and pick every second note three times. Both are built from the first five harmonics, so the major triad effectively sounds whenever a resonant note is played.
Two further triads exist but are far less common and are not yet used in NoSheet. The diminished triad (two stacked minor 3rds) also arises once within the major modes. The augmented triad (two stacked major 3rds) divides the octave evenly but is very tense, used occasionally as a color chord in jazz, classical, and psychedelic rock.