The Santoor [santur] has the shape of a trapezoidal box, the sides of which form a 45° angle with the same. Strings are attached to the left side and tuned by turning metal pegs on the right with a key. Each group of strings is stretched over a movable hard wood bridge. Bridges are placed parallel to the sides of the trapezium. On the right, a line for the low strings, and on the left, one to support the top strings.

The left strings can be sounded to either side of ther bridges, giving in all three different string systems. With 72 strings disposed in two times 9 groupe (9 bronze in low register and 9 steel in middle register), 27 différent sounds can be obtained, a rang of a little over three octaves.

In the Orient, the fundamentals of this instrument are no doubt very ancient. It seems that the origin of Santoor goes back to assyriennes and babyloniennes, sixth century B.C. Even though the Persian Santoor has remained a marginal instrument, never depicted on miniatures prior to the 19th century, the period when several performers developped an extremely refined technique, enabling it to render all the finesses of Persian music. At that time, the instrument has taken its most perfect form.

The Santoor is played by striking the strings with two light sticks (mezrab [mezrAb]) held in the three fingers of the right and left hands. 'Modernists' have covered the tips of the sticks with felt to soften the impact and come close to a piano sonority, but traditional aesthetics require a fine, precise sonority only to be obtained with light hard-wood sticks.

The secret of making the trapezoid-shape sound box lies in the quality and age of the wood, as well as in the arrangement of the soundposts which connect the table of the instrument to its back.