In recent times there exists two types of Sitars, with corresponding playing styles and sounds. The first is known as the Vilayat Khan style sitar, and the second is known as the Ravi Shankar style sitar.
The V.K. style sitar is slightly smaller and has far less wood carving decoration than the R.S. style sitar. The R.S. style sitar often has a second small pumpkin attached near the top of the neck and two extra bass strings. V.K. style sitars do not have these bass strings but instead have one extra chickary (rhythmic accompaniment strings) string that allows for a fuller, more chordal chickary effect to be produced.
The Sitar's neck and face are made of Indian mahogany and its round back/base is of a dried pumpkin. Although the Sitar has a minimum of eighteen strings, it generally has just one main playing string. The remaining strings provide it's ethereal resonance and/or resonance plus rhythmic accompaniment. The Sitar has two separate bridges, one upper, and one lower. The upper contains the playing string(s) and the chickary strings (used for rhythmic and drone accompaniment). The lower bridge usually has about twelve tarif (sympathetic) strings, which are very fine and are tuned to the notes of the Raga (scale) being played. These strings, when tuned accurately, will resonate without being touched when a corresponding note is played on the upper main string, thus giving the sitar a natural reverb effect. This effect is enhanced by the structure of the bridge. Copied from the ancient tampura (a background drone instrument used primarily to accompany vocal music) the Sitar's bridge is made of soft deer-horn and is flat on top and is shaped in such a way as to allow the strings to gently buzz against the flat bridge surface. This effect is called jawari.
The Sitar is a fretted instrument but the frets (metal bars) are tied on loosely enough to be slightly moved or tuned. The tuning of the frets is another feature that sets the sitar apart from western instruments. The Sitar is played in the natural or untempered tuning system. Many western instruments such as the guitar and the piano are designed to be played in the equal-tempered tuning system that is a modern invention without which the chordal harmony and 12 keys of western music would be impossible to achieve from a single instrument. The disadvantage of the tempered system is that it is microscopically out of tune. The Ancient, Natural, or untempered tuning system retains the perfect or natural tuning of each interval. It is believed that music played in the Natural tuning system has a profoundly harmonizing effect on listeners.
The most striking feature of the Sitar's playing technique is it's main strings capacity for being pulled or bent. On one fret the main string can be pulled downward at least a fourth; for example from C to G. This particular feature has only been available during the last fifty years - since steel strings have been made with enough strength to withstand such tension. This pulling capacity allows the instrument to accurately emulate the gliding effect of vocal music.