Sitar

The sitar has 2 bridges; the main bridge (the bada goraj) for the playing and drone strings and a smaller, secondary bridge (the chota goraj) for the sympathetic strings that run beneath the main strings. The sitar may or may not have a secondary resonator, the tumba, near the top of its hollow neck. The sitar's distinctive sound is a result of the way the strings interact with the wide, sloping bridge. This is in contrast to the bridge on a guitar which resembles a knife edge. In a sitar, as a string vibrates, its length changes slightly as its edge touches the bridge, promoting the creation of overtones and giving the sound its distinctive, rich tone. The maintenance of this specific tone by shaping the bridge is called "jawari". Adjusting the jawari requires great skill. Many professional musicians will rely on professional instrumental makers to perform this task. For years Ravi Shankar toured the West with his sitar maker so that the tone of his sitar was always perfectly adjusted. Many professional sitarists also travel with 2 bridges - one for daily wear practising, and a fine tuned one for performing.  The materials used in construction include teak wood or tun wood (Cedrela tuna) for the neck and faceplate, and gourds for the kaddu (the main resonating chamber) and the aforementioned tumba. The instrument's bridges are deer horn.
 

Tuning

The tuning of a sitar varies depending on sitarists school or style. Generally, the main playing string is tuned to C# or D, and the drone strings are tuned to the equivalent an open major or minor chord in Western music theory. The specific tuning for each raga is determined by tradition and each artist's personal preference. The sympathetic strings are tuned to the notes of the raga being played, although there is slight stylistic variance as to the order of these. The player will usually retune the sitar for each raga. The strings are tuned by turning the pegs that hold the strings. The main playing strings are fine-tuned by sliding a bead fit around each string. It may be rather difficult to tune a sitar. Not only because of the numerous strings (a typical electric guitar only has six strings) or the lack of geared mechanical tuners (sitar tuning pegs are wood cylinders that are chalked and tightened into a hole like traditional western classical music instruments such as the cello), but also because there are many different tunings, each based on the cadre of traditional and emerging tonal patterns or on the music of eminently influential sitar players. 
 

In one or more of the more common tunings (used by Ravi Shankar among others) the strings are tuned in this fashion: The Chikari, Sa (high) Sa (middle) Pa. The Kharaj strings (bass strings) Sa (low) Pa. Then, Sa and Ma. When playing a Vilayat Khan Sitar (or "Gayaki" Sitar), the bass strings are removed and in their place is a 4th Chikari which is tuned to Ga, when playing the chikari you produce a chord (Sa, Sa, Pa, Ga). The sympathetic strings (tarif) are tuned depending on the raga, although for most purposes, they are tuned: Sa, Ni, Sa, Re, Ga, Ma, Pa, Pa, Dha, Ni, Sa, Re, Ga, (last three in the upper range). If you were to tune it to rag Kafi for example you use tune as follows: Sa, ni (lower case denotes flat or, more properly, "komal") Sa, Re, ga, Ga (Shuddh ("natural"), considering that in Kafi you will come to Shuddh Ga when descending or "Avarohi"), ma, Pa, Dha, ni, Sa, Re, ga. Whereas, in ragini Yaman Kaylan you will tune the Tarifs to Sa, Ni, Sa, Re, Ga, ma (Yaman Kaylan asks for a sharp, or more properly, "tivra" Ma, but often will touch shuddh ma on the descent or "Avarohi"), Ma, Pa, Dha, Ni, Sa, Re, Ga. Again, however, there is a lot of stylistic variance to these tunings. An artist will develop a particular tuning for a particular piece and it may be totally idiosyncratic. There is no guarantee that other musicians will choose the same tuning even if they perform the same raga.