In appearance the santoor is a rectangular box over which strings of varying length are stretched. The long side of the rectangle faces the performer and the strings run parallel to the longer side. Unlike the swararnandal which has only one string to a note, the santoor has generally a set of three strings to a note. The length and the thickness very accor¬ding to the octave; the strings are thickest in the lower octave. Its speciality, which distinguishes it clearly from the swararnandal is its method of note production. In the swaramandal the strings are plucked by the fingers, whereas in the santoor, the strings are subjected to pressure strokes by small wooden hammers held in both the hands.
The same principle is aj5plied in the making of the modern pianoforte where the strings are struck by mechani¬cal keys. The disadvantage is obvious; when the strings are struck, the sound of the notes lingers on and cannot be cont¬rolled. The santoor is popular in the Middle East. In India, it is special to Kashmir where the instrument is used for accom¬panying a type of classical music called Soofiana Kalam, along with other instru¬ments of the region, like the saz, the rabab, the sitar, the sarangi, the tumbak¬nari, and the ghata.