Mondo Knows Facts
Equal temperament divides the octave into twelve equal steps
Each semitone multiplies frequency by the twelfth root of two The ratio is about 1.0595, so no interval except the octave is perfectly pure. The compromise lets a keyboard play in every key without retuning. Most Western instruments are built to this system today. It sits in Mondo's music collection, one of 200 facts that each trace back to the reference below.
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More facts like this
Twelve pure fifths overshoot seven octavesThe gap is called the Pythagorean comma, about 23 centsA guitar is tuned mostly in fourthsE, A, D and G are fourths apart, with a third gap before BMusicians tune by listening for beatsTwo nearly matched frequencies produce a slow throb that stops when they agreeWarm air makes instruments play sharpSound travels faster as temperature rises, lifting the pitch of wind instrumentsOrchestras tune to A at 440 hertz by international agreementThe standard was agreed in London in 1939Orchestras tune to A at 440 hertzThat number was agreed internationally only in the twentieth century
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Tags: temperament, tuning, mathematics
Equal temperament divides the octave into twelve equal steps: the short answers
- Where does this come from, and can I check it?
- Each semitone multiplies frequency by the twelfth root of two. The figure is taken from Britannica, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
- Is this really a music fact?
- Yes. It sits on the Music shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
- What else can I read about it?
- The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.