A sound relationship between frequencies
An octave occurs when one note's frequency is exactly double another's. Your brain perceives these two pitches as fundamentally "the same note" — just higher or lower. It's a harmonic coincidence that really resonates with people.
Hertz so good when you hear it.
Tap any key below. Notice how both A notes (highlighted) sound like the same pitch at different heights? Don't worry — we won't string you along.
A4, the tuning standard, vibrates at 440 times per second. A5 vibrates exactly 880 times. Twice the frequency, same musical identity. It's note complicated.
When you play them together, they're pitch perfect partners.
Pick any base frequency. Its octave is always double. The math scales beautifully — no sharp edges here.
Go ahead, slide around. We're on the same wavelength.
The 2:1 ratio is nature's favorite interval. It's why we name notes in repeating cycles (A, B, C... then A again). Every musical scale, from ancient modes to modern pop, rests on this foundation.
When waves align in simple ratios, they sound consonant. The octave is the simplest ratio of all — and that's something we can all tune into.
It's sound science, really. We're not just making this up flat.