What Are Consonance and Dissonance?
What Are Consonance and Dissonance?
Consonant intervals sound stable, blended, at rest; dissonant intervals sound tense, clashing, in need of motion. Neither is "good" or "bad" — music is the traffic between them. A piece of nothing but consonance is wallpaper; nothing but dissonance is noise.
The rough spectrum
From most consonant to most dissonant:
- Octave and unison — so blended they read as "the same note"
- Perfect fifth and perfect fourth — open, hollow, strong
- Major third, minor third, and sixths — sweet, colorful; the sound of chords
- Seconds and sevenths — spicy, rubbing
- The tritone — maximally restless
The ranking isn't arbitrary taste: it tracks how early an interval appears in the harmonic series. Simpler frequency ratios blend better; the octave is 2:1, the fifth 3:2, while dissonant intervals have gnarly ratios your ear can't reconcile.
Why guitarists should care
Harmony is tension management. A dominant seventh chord works because it plants a dissonant tritone inside a chord and then resolves it — that's a cadence. When a note in your solo "clashes," you've landed on a dissonance against the current chord; chord-tone targeting is the craft of choosing when to rub and when to resolve.