Arab tone
system
The modern
Arab tone system, or system of musical tuning, is based upon the
theoretical division of the octave into twenty-four equal
divisions or 24-tone equal temperament (24-TET), the distance
between each successive note being a quarter tone (50 cents).
Each tone has its own name not repeated in different octaves,
unlike systems featuring octave equivalency. The lowest tone is
named yakah and is determined by the
lowest pitch in the range of the singer. The next higher octave
is nawa and the second
tuti. (Touma
1996, p.17-18) However, from these twenty-four tones seven are
selected to produce a scale and thus the interval of a quarter
tone is never used and the
three-quarter tone or neutral second should be considered the
characteristic interval. (ibid, p.23)
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 the system is written in European musical notation
using a slashed flat for quarter flat, a flat for half-tone
flat, a slashed flat and a flat for three-quarter tone flat,
sharp with one vertical line for quarter sharp, sharp (♯)
for half-step sharp, and a half sharp and a sharp for
three-quarter sharp. A two octave range starting with
yakah arbitrarily on the G below
middle C is used. (ibid, p.24)
In practice
far 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).
(ibid, p.24-25).
The specific
notes used in a piece will be part of one of more than seventy
modes or maqam rows named after characteristic tones which are
rarely the first tone (unlike in European-influenced music
theory where the tonic is listed first). The rows are
heptatonic and constructed from
augmented, major, neutral, and minor seconds. Many different but
similar ratios are proposed for the frequency ratios of the
tones of each row and performance practice, as of 1996, has not
been investigated using electronic measurements. (ibid, p.18)
Actual practice is estimated to vary within a quarter
tone from notation.
The current
tone system is derived from the work of al-Farabi (d. 950 CE) (heptatonic
scales constructed from seconds) who used a 25 (unequal) tone
scale (see tetrachord), with
Mikha'il
Mishaqah (1800-1889) first presenting the 24 tone equal
tempered division. (ibid, p.19)
References
•
Habib Hassan
Touma (1996). The Music of the Arabs,
trans. Laurie Schwartz. Portland, Oregon: Amadeus Press.
ISBN 0-931340-88-8.