Oud later), tuned in successive fourths. Curt Sachs said they were called (from lowest to highest pitch) "bamm", "maṭlaṭ", "maṭnā" and "zīr". "As early as the ninth century" a fifth string "ḥād" ("sharp") was sometimes added "to make the range of two octaves complete". It was highest in pitch, placed lowest in its positioning in relation to other strings. Modern tuning preserves the ancient succession of fourths, with adjunctions (lowest or highest courses) which may be tuned differently following regional or personal preferences. Sachs gives one tuning for this arrangement of five pairs of strings, d, e, a, d', g'. Historical
Scientific pitch Pyke Hullah in the mid-19th century, but never established as a standard. In the 19th century, Italian composer Giuseppe Verdi tried to stop the increase in pitch to which orchestras were tuned. In 1874 he wrote his "Requiem" using the official French standard "diapason normal" pitch of A4 tuned to 435 Hz. Later, he indicated that 432 Hz would be slightly better for orchestras. One solution he proposed was scientific pitch. He had little success. In 1988, Lyndon LaRouche's Schiller Institute initiated a campaign to establish scientific pitch as the classical music concert pitch standard. The Institute called this pitch