The Tanpura is a four to six stringed fretless instrument made of wood, and usually combined with gourd. It provides the performing artist(s) with a tonic reference and enriches the background with its unique harmonic drone. The strings are tuned in a manner that emphasizes the tonic and the dominant notes of the raag. The bridge is slightly curved to not only provide a buzzing sound (as the strings are plucked), but also to generate various harmonics that enhance the tonal quality of the instrument. The size (gourd and neck) of the instrument may vary depending on whether the artist is an instrumentalist, male vocalist, or a female vocalist. Tanpura was most probably included as a part of a classical music ensemble since the seventeenth century.
