The Sitar and the Sarod evolved concurrently and interactively in the 18th and 19th centuries as major solo instruments in Hindustani music. Both being plucked lutes, they also cultivated a shared format for Raga presentation. Their protocol was later also found suitable for the percussive-melodic instrument, the Santoor, and adopted by its performers.
The first Phase of a Sitar/Sarod/Santoor performance is an entirely improvised solo, without percussion accompaniment. It has three movements: This phase can consume 40-50% of the duration of the presentation.
1. The first movement is called the Alap, which is an entirely improvised free flowing melodic movement. It consists of low-density melody, without explicit pulsation or rhythm. Along with this, the movement also features a systematic perforation of the melody by the harmonic ambiance of the tuned instrument.
2. The second movement is called Jod. In this the melody is medium density, and acquires a simple 2-beat pulsation. In this movement, the structured use of the harmonic ambiance of the instrument is deployed more actively than in the Jod movement.
3. The third movement is called the Jhala. This movement consists of high-density melody with a structure approximating a 4/6/8 beat rhythmic cycle. The melody is perceptibly more complex, with even elements of harmony entering the music. The Jhala raises the first phase presentation to a crescendo before it ends.
This Alap-Jod-Jhala phase of solo music is carried over from the protocol of the Rudra Veena (also a plucked string instrument), which was the primary instrument of the Dhrupad era.
In the second phase of the performance, the musician presents a slow-tempo composition to percussion accompaniment. Logically sequenced improvisations are inserted into the frame of the composition. Slow tempo compositions are generally performed at a tempo of 45-60 beats per minute. This phase can consume 30-40% of the duration of the presentation.
In the third phase of the performance, the musician presents a fast-tempo composition, also to percussion accompaniment, and with logically sequenced improvisations inserted into the frame of the composition. These compositions are generally performed at a tempo of 150+ beats per minute, and undergo a steady escalation culminating in a crescendo at over 300 beats per minute. This third and final phase of the presentation can take up 10-20% of the duration.
Phase II and Phase III of the Sitar/Sarod protocol mainly represent post-Dhrupad musical idioms. They could belong either distinctively to the the plucked lutes, or exhibit the influence of the modern Khayal vocalism.