Arab tone system
The modern Arab tone system, or system of
By contrast, in the European equally tempered scale the octave is divided into twelve equal divisions, or exactly half as many as the Arab system. Thus, when Arabic music is written in European musical notation, a slashed or reversed flat sign is used to indicate a quarter-tone flat, a standard flat symbol for a half-tone flat, and a flat sign combined with a slashed or reversed flat sign for a three-quarter-tone flat, sharp with one vertical line for quarter sharps, standard sharp symbol (♯) for a half-step sharp, and a sharp with three vertical lines for a three-quarter-tone sharp. A two octave range starting with yakah arbitrarily on the G below middle C is used.[3]
In practice much fewer than twenty-four tones are used in a single performance. All twenty-four tones are individual pitches differentiated into a hierarchy of important pitches—pillars—which occur more frequently in the tone rows of traditional music and most often begin tone rows, and scattered less important or seldom occurring pitches (see tonality).[4]
The specific notes used in a piece will be part of one of more than seventy
The current tone system is derived from the work of