25.1 · Sound Itself
The harmonic series
A string playing C doesn't just vibrate whole. It also vibrates in halves, thirds, and quarters, all at once, and each division adds a quiet pitch above the note: the harmonic series. Every note you've ever heard is secretly a stack. Octaves, fifths, and the major chord are its first rungs.
The ladder over one low C
The first eight rungs, played loud so you can meet them. In a real note they all sound at once, quietly, inside the one pitch you name.
Why octaves and fifths feel clean
Two notes agree when their ladders share rungs. An octave shares every other rung; a fifth shares every third. The more overlap, the smoother the blend. That's the consonance you'll measure in the next lessons.
Quiz
1 / 3The harmonic series exists because a string…