Ph.D. Instrumental music occupies an important position in Indian music. There is a general tendency for the instrumental styles to follow quite closely the vocal styles . Yet, the degree to which an instrument follows is primarily linked to the dynamics of the instrument.
Dynamics is the nature of the loudness of an instrument.
This is not intended to mean loudness in the usual interpretation, but rather the amplitudinal characteristics of the instrument. The sitar and flute offer a good illustration. A flute is continuously excited, therefore there is a steady sound as long as the breath is applied. Instruments with a long sustain tend to follow the vocal styles in their presentation. Contrast this to a sitar with its rapid decay.