Sound explorer
See the overtones of any sound. Strike a piano note, or two together, and watch its partials appear in the spectrum. The explorer names the notes it finds and shows how far each partial sits from an exact multiple of its fundamental. It is for learning; to tune, use the Temperament wizard.
Spectrum
Frequency runs left to right, one equal step per octave; height is loudness in decibels below the loudest partial. Each peak is a partial. The numbered markers show the partials of the selected note.
Notes found
None yet.
Key numbers as in the book: A49 is A4, 440 Hz. Cents are the distance from that key in equal temperament. The bar is each note's strength against the strongest.
Partials
| Partial | n × f0 (Hz) | Measured (Hz) | Stretch (cents) | Confidence |
|---|
Stretch is how far the measured partial sits above the exact multiple n × f0, in cents. Confidence says how clearly a partial was measured. Greyed rows should not be trusted: they are weak, or far from the spectrum peak, which usually means another note's partial was measured.
What you are seeing
Partials
A string vibrates as a whole and in halves, thirds, quarters and so on, all at once. Each way of vibrating sounds its own frequency, a partial. The first partial is the fundamental, the pitch you name; the others are what make a piano sound like a piano. Notes marked faint are often real but quiet sounds in the recording, such as the body of the instrument resonating or other strings ringing along.
Why piano partials are stretched
An ideal string would put partial n at exactly n times the fundamental. Piano wire is stiff, which pushes each partial a little higher, and the higher the partial the more it is pushed. This is inharmonicity. The table measures stretch against an f0 fitted to all the clear partials, so partial 1 can sit slightly off zero and a real recording adds some scatter, but on a piano the trend shows: the higher the partial, the more it is stretched. Values read from the spectrum peaks are rougher still.
Why partials make beats
When two notes share a partial, say the 4th of one and the 3rd of the other in a fourth, the two partials almost coincide. If they differ by a few hertz you hear the sound swell and fade that many times a second. Tuners set intervals by counting these beats. Learn to hear them in the Beat trainer, then set a temperament with the Temperament wizard.