This paper explores a new and ambitious tuning system for the Middle Eastern qānūn, conceived and practiced by the French virtuoso Julien Jalâl Ed-Dine Weiss (b. 1953). Since the invention of mandal-s, movable bridges that enable microtonal alterations during performance, the qānūn has become a major source for tuning and fixation of the Middle Eastern pitch inventory. Whereas Arab qānūn-s are based on "quarter tones", Turkish instruments divide the octave into 72 notes. All commonly fabricated models, however, have in common that their tuning is based on 12-semitone equal temperament. This does not conform with the Pythagorean tuning on which the heptatonic framework of the qānūn is traditionally based. For that reason, common qānūn models only approximate the interval sizes that have been described throughout the theoretical tradition by means of arithmetic ratios. Equal temperament causes transformations in the tuning of commonly agreed scale degrees and complicates the qānūn's interaction with
both justly tuned and fretless instruments to an audible extent.

As the founder of the internationally acclaimed Al-Kindi ensemble, Weiss has repeatedly criticized this deficiency. Since 1990, he has constructed nine qānūn prototypes with which he performs in diverse regional contexts within the Middle-Eastern tradition. As the outcome of many years of practical experience, Weiss's qānūn models currently offer the widest range of microtones in strictly just intonation. At the same time, their tuning remains truthful to the theoretical approaches of the major historic treatises. This study explores Weiss's motivations in regard to the principal developments of the Middle Eastern fundamental scale. The discussion includes those tuning approaches from the recent past that influenced Weiss in the conception of his prototypes: the professional Arab qānūn prior to the 1970s, the frets on Necdet Yaşar's Turkish tanbūr, and the qānūn of Aleppo that vanished in the 1980s.

Weiss's approach reveals that the tuning system of the transnational maqām phenomenon has spread to such complexity that its fundamental supply of pitches cannot be thought of except in terms of local variations in a plurality of traditions. His instrumental prototypes may reconcile the diverse scholarly approaches with both practical and theoretical objectives.