The Great Book of Music

...the strings in the tetrachords tetrachords: "al-ajnas al-lati bi-l-arba'a nagham," groups of four notes that serve as the foundational building blocks of scales.. He discussed the tuning of open strings open strings: "al-awtar al-mutlaqa," strings played without being pressed down, producing their fundamental pitch. by means of sensory perception through "small consonances," which is the method most commonly used by those who play these instruments. Then, he followed this with a general statement on stringed instruments and the ways in which scientific principles can be applied to determine the exact placement of notes upon them.

As for the third art or "third section" of this part, he dedicated it to the composition of notes, the methods of melodies, and the craft of specific musical pieces. He organized it into two treatises:

The first: on the definition of the first of two types of melodies, which is the music heard as pure sound instrumental music. For this reason, he organized the complete disjunct systems complete disjunct systems: "al-jama'at al-tamma al-munfasila," complex scale structures spanning two octaves, used to organize all possible notes in a musical system. into tables according to the "strong genera" or "soft genera" original: "al-ajnas al-qawiyya" and "al-ajnas al-layyina," referring to Diatonic (strong) and Chromatic or Enharmonic (soft) interval arrangements used in each. He explained the consonances and dissonances of every note in relation to others within each group. Then, he spoke about the types of transitions modulations between different scales or modes between notes and the starting points from which one moves within a group. He also mentioned the durations of rhythms rhythms: "al-iqa'at," the proportional measurement of time between notes., their construction, their simplification, and the changes that affect their fundamental types. He mentioned the varieties of rhythms famous among the ancient Arabs, and the editor has provided commentary on the contemporary rhythms that correspond to them today.

The second treatise of this art is dedicated to the composition of specific melodies. He first defined the second of the two types of melodies: that which is produced by human vocalization joined with words that convey meaning. He then enumerated the categories of notes and their qualities, voiced and unvoiced letters, the components of letters and the components of notes, and how notes are joined to the letters of speech. He then divided human melodies into three classes; among them are "empty melodies," which is the class where the letters of the speech are spaced so far apart during the composition that the form of the...