Over the centuries, distinct local musical practices have developed, forging a cultural identity specific to each society. There are thus, in Maghreb cities such as Fez, Tetouan, Tlemcen and Tunis, distinct versions of the nûbas, which are an integral part of the local musical culture. In music theory, a scale is a set of musical notes ordered by fundamental frequency or pitch. A scale ordered by increasing step is an ascending scale, and a scale ordered by decreasing step is a decreasing scale. Scales in traditional Western music usually consist of seven notes and repeat at the octave. Despite the enormous development of technologies in the field of music, most musical instruments only support 12-note European denominators, which makes playing Arabic music on modern instruments difficult.