12oktav

12oktav is a term used in music theory to describe the standard division of the octave into 12 equal pitch steps, commonly known as twelve-tone equal temperament (12-TET). In this system, the octave is divided into 12 semitones, and the pitch classes within one octave are typically labeled as C, C#/Db, D, D#/Eb, E, F, F#/Gb, G, G#/Ab, A, A#/Bb, and B. After the B, the next pitch is C at double the frequency, repeating the cycle.

The frequency ratio between adjacent semitones is the twelfth root of two, about 1.05946. This uniform spacing allows easy transposition and modulation between keys, which is why 12-TET became the standard in Western music from the Classical period onward. It also enables equal treatment of all keys, though it sacrifices the pure consonance of just intonation for most intervals.

Historically, many tunings existed before 12-TET, such as meantone and various well-temperaments. By the 18th and 19th centuries, 12-TET became dominant in Western music, particularly for keyboard instruments and ensembles that require consistent tuning across keys. While 12-TET is widespread, alternative temperaments and microtonal systems exist, offering different splits of the octave beyond the 12-semitone division. The term 12oktav is thus closely associated with the practical and theoretical framework of the 12-tone equal temperament used in much of modern Western music.