Indian musical instrument . The dhol !.
The sitar's curved frets are movable, allowing fine tuning, and raised so that sympathetic strings (tarb, also known as "taarif" or "tarafdaar") can run underneath them. A sitar can have 21, 22, or 23 strings, among them six or seven played strings which run over the frets: the Gandhaar-pancham sitar (used by Vilayat Khan and his disciples) has six playable strings, whereas the Kharaj-pancham sitar, used in the Maihar gharana, to which Ravi Shankar belongs, and other gharanas such as Bishnupur, has seven. Three of these (or four on a Ghandar-pancham sitar or "Vilayat Khan" style aka Etawa gharana), called the chikaari, simply provide a drone: the rest are used to play the melody, though the first string (baajtaar) is most used.
The instrument has two bridges; the large bridge (badaagoraa) for the playing and drone strings and the small bridge (chotagoraa) for the sympathetic strings. Its timbre results from the way the strings interact with the wide, sloping bridge. As a string reverberates its length changes slightly as its edge touches the bridge, promoting the creation of overtones and giving the sound its distinctive tone. The maintenance of this specific tone by shaping the bridge is called jawari. Many musicians rely on instrument makers to adjust this.
Materials used in construction include teak wood or tun wood (Cedrela tuna), which is a variation of mahogany, for the neck and faceplate (tabli), and gourds for the kaddu (the main resonating chamber). The instrument's bridges are made of deer horn, ebony, or very occasionally from camel bone. Synthetic material is now common as well. The sitar may have a secondary resonator, the tumbaa, near the top of its hollow neck.