The santūr is a trapezoid-shaped case, approximately ninety centimeters wide at the broad end and thirty-five centimeters at the narrow end. The seventy-two strings form eighteen quadruple sets of strings, nine (bronze) in the low register, and nine (steel) in the middle register. They are struck with light wooden hammers (Mezrāb), held by five fingers of each hand. Santūr is very old, and there are some archeological evidence which shows that the age of the instrument goes back to 669 BCE. A type of santūr is supposed to have been known to the Hebrews under the name of Psanterin, and was brought to Europe from the east by the Crusaders, introducing the prototypes of the dulcimer and psaltery common during the Middle Ages.
In the seventeenth century, its shape was very similar to the present-day Iranian Santur. Variants of this Santur are found in China, Turkestan, India, Iraq, and Turkey, but it should be recognized that in nine of these traditions has the technique and sophistication of touch as far as in Iran. Today the Santur is played widely in the Orient, from Iraq to India. The santūr is three octaves, diatonic instrument and has to be tuned for each mode or dastgāh. The lowest note is e1, which is located on the first bridge on the right. The highest note is f3, which is located on the ninth bridge on the left in the third position.
