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21.1 · Sound Itself

Same note, different voice

Play C3 on a piano and on a marimba: same pitch, same loudness, unmistakably different voices. That difference is timbre. Every real note is a bundle: a fundamental wave plus quieter overtones stacked above it. Each instrument mixes that bundle its own way, and the mix is the voice.

Watch the wave change

This is the app's live waveform, up close. Play the same C3 on four instruments and watch the wiggle change shape while the pitch stays put.

bright attack, singing middle, slow fade
glassy, hollow, almost bell-like
plucked snap, warm and woody
a knock that blooms and vanishes

A smoother, rounder trace means fewer strong overtones. A jagged, busy trace means many. Same fundamental frequency every time: that's why it stays the same note.

Why octaves sound like family

Overtones also explain why octaves blend: A4's strongest overtone is A5 itself. Play them together and the overtones interlock like gears.

Quiz

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Two instruments play the same pitch. What makes them sound different?

Score 100% on every quiz and game to complete this lesson.Rough or smooth →