Music Theory Basics
Why do some notes sound good together? Discover the math behind music.
Why do some notes sound good together? Discover the math behind music.
Every musical note is just air vibrating at a specific speed. The faster it vibrates, the higher the pitch.
This is the standard tuning note. All instruments tune to this frequency.
An octave is the interval between one note and the next note with the same name. It spans 8 white keys on a piano (C to C, A to A, etc.).
Here's the amazing part: going up one octave means exactly doubling the frequency. A4 (440 Hz) → A5 (880 Hz). They sound like the "same" note, just higher!
Humans can hear frequencies from about 20 Hz to 20,000 Hz - roughly 10 octaves! Dogs can hear up to 65,000 Hz, which is why dog whistles work. A piano spans about 7 octaves, from 27.5 Hz to 4,186 Hz.
Western music uses just 12 notes, repeating in higher and lower octaves. This is the chromatic scale.
C, D, E, F, G, A, B - the "natural" notes that make up the C major scale.
Sharps (#) and flats (b) - the notes "in between" the naturals.
After 12 notes, you're back where you started - just one octave higher!
Each piano key is about 5.95% higher in frequency than the previous one. This ratio (the 12th root of 2) divides the octave into equal steps.
The same notes can sound happy or sad depending on the pattern. This is the "mood" of music.
Happy, bright, triumphant
Sad, dark, mysterious
Major has a "major third" (4 half-steps up). Minor has a "minor third" (3 half-steps up).
C Major: C-E-G. C Minor: C-Eb-G. Just one note changes the whole mood!
Movie composers use minor keys for villains and major keys for heroes. Hans Zimmer's "Imperial March" (Darth Vader) is in G minor!
Chords are built by stacking notes. A basic triad has 3 notes: root, third, and fifth.
The foundation note - the chord is named after this note.
Determines major (happy) or minor (sad) quality.
Adds stability and power to the chord.
Power chords in rock music are just root + fifth, no third! This makes them neither major nor minor - just powerful.
Songs are built from sequences of chords. Some patterns are so common they appear in thousands of songs!
Musicians use I, ii, iii, IV, V, vi, vii to name chords by their position in a key.
This progression appears in "Let It Be", "No Woman No Cry", "With or Without You", and hundreds more!
The "Axis of Awesome" comedy group famously performed a medley of 36 hit songs that all use the same I-V-vi-IV progression!
You've discovered the building blocks that make music work. Now you understand what musicians have known for centuries!
Higher frequency means higher pitch. Double the frequency = one octave up.
All Western music uses just 12 notes arranged in different patterns.
The third note of a chord determines its emotional quality.
Chord sequences create tension and resolution - the narrative of music.
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