Chord Science: Why Notes Sound Good Together
The math hiding inside every beautiful chord
The math hiding inside every beautiful chord
Every musical note is a vibration at a specific frequency. Higher frequency = higher pitch. The note A4 vibrates at exactly 440 Hz (440 times per second). Click notes on the piano to hear and see their waveforms.
Click a key to hear the note and see its waveform.
The interval between two notes determines whether they sound harmonious or tense. Simple frequency ratios (like 2:1 or 3:2) sound smooth. Complex ratios sound rough. Click each interval to hear and compare.
Click an interval to hear two notes played together.
Pythagoras discovered musical intervals around 500 BC by noticing that a blacksmith's hammers sounded harmonious when their weights were in simple ratios. He built the entire Western scale from the 3:2 ratio.
A chord is three or more notes played together. The type of chord changes the emotional feel completely. Click each chord to hear the difference.
Click a chord to hear it.
The same physics that determines consonance and dissonance is why music triggers emotions. Composers have used these principles for centuries.
Major chords, rising melodies, fast tempo. Think of a national anthem or a victory fanfare. Major thirds create brightness.
Minor chords, descending melodies, slower tempo. The minor third flattens the brightness, creating a wistful, reflective quality.
Diminished and augmented chords, tritones (the "devil's interval"), unresolved dissonance. Horror movies live here.
Open fifths, suspended chords, slow arpeggios. Removing the third makes the chord neither major nor minor, creating ambiguity and calm.
The "Jaws" theme uses just two notes a semitone apart (a minor second). This is the most dissonant interval, and the slow repetition triggers a primal fear response. Two notes. That is all it takes.
You've discovered why some note combinations sound beautiful and others clash. It all comes down to frequency ratios. Simple ratios = consonance. Complex ratios = dissonance.
Every note is a vibration at a specific frequency. A440 means the air vibrates 440 times per second.
An octave is 2:1. A perfect fifth is 3:2. The simpler the ratio, the more consonant (pleasant) the sound.
A major chord has a major third (4 semitones). Change it to a minor third (3 semitones) and the mood completely shifts.
Dissonant chords are not bad. They create tension that resolves into consonance, giving music its emotional power.
Put your new knowledge into practice!