The Tanpura is used to provide a background drone of the tonic and the dominant, or the tonic and the subdominant or some other suitable note according to the Raga being presented. It is on the backdrop of this continuously sounding drone that the vocalist or the instrumentalist fixes his or her pitch during the course of a performance.

The practice of having an instrument to fix the pitch of the vocalist is an ancient one. In very ancient times such as the Vedic Age (before 1500 BC) or the Post-Vedic and Pre-Pouranic Ages (from 1500 BC to about 700 BC) the Vana Veena was used with the style of art music known as Samagana to fix the pitch of the vocalist. Thereafter, a single-stringed drone instrument, called the Dandi (literally, "pole") was used for the same purpose. By and by, one string after another was added to the Dandi and by the 15th or 16th century AC, the Tanpura in its present form of four strings was universally adopted.

The four strings may be grouped into three categories: the middle two strings, which are tuned to the tonic, the fourth string, which is the thickest and is tuned to the low tonic and finally the first string, which is thicker than the middle two but less so than the fourth string -- this (first) string is tuned to the dominant or other predominant note of the Raga being presented.

In course of time a fifth and even a sixth string has been added to the Tanpura, so that the artist could get a more interesting harmonic backdrop or carpet of sound on which to sing/play. However, the standard four stringed instrument is still the overwhelmingly popular one and capable of doing all that an unobtrusive and soothing background drone instrument should do. (Dr Rath and Prof Mukerji have even seen, on one occasion, a seven-stringed Tanpura, but this, it is submitted, should be discounted and written off as a mad monstrosity!)