In the south, ensembles are rather flexible where their choice of instruments for fulfilling traditional roles is concerned. However, their roles remain clear. A flute solo may be accompanied by the mridanga alone, or by the mridanga together with the ghatam or kanjira, or by one of the latter without the mridanga. For the purposes of melodic support, the flute may be joined by a violin or by another flute. The same type of flexibility is found also with veena, violin, and especially vocal-solo ensembles. The role of the supporting melodic instrument is one of partnership with the soloist.
In the case of North Indian ensembles however, the musical roles of the respective instruments differ with the performance genre. For instance, the drum is given different roles in vocal genres. In the case of Dhrupad, the pakhavaj player tries to match the rhythm of the song in a supportive partnership. In Khayal, the drummer functions as a timekeeper. He is supposed to repeat the theka of the particular tala again and again. This same role is also maintained in gayaki-style instrumental performances. In thumri, the drumming is less restricted in that the laggi section gives the drummer a chance to play in the spotlight. Only in the case of a solo Hindustani instrumental performance does he participate in a kind of partnership with the melody-producing soloist.
In Hindustani ensembles, the role of accompanying stringed instrument is more constant. The role of the sarangi (and harmonium) is to shadow and thus support the melody of the soloist. The sarangi is used precisely because it is deemed most suitable for imitating the display of virtuosity, even the tonal quality, of a voice. Onstage, the tambura player just keeps plucking, keeping the drone steady. He too, will respond to a finely turned phrase. The accompanying stringed instruments join the soloist right from the beginning. When the drummer is not playing in the un-metered portions of a performance, he will also listen attentively; the soloist looks for his responses.
The reactions of the audience comprise a major portion of a musical performance. Throughout a musical performance, be it Hindustani or Carnatic style, the audience is mostly musically educated. They listen closely and keep tala with their hands or in their head. The audience follows closely and reacts audibly and visibly when a fine phrase has been made. Reactions flow back and forth throughout a lengthy selection. The reactions of the audience are a must for the performer as it keeps the energy alive.
In Carnatic music, the inter-relationship between the different performers in the ensemble is more like a partnership. The ragam-tanam-pallavi sequence in Carnatic music is structured according to this principle of partnership. In ragam, a vocal soloist first sings alapana, and the violinist then follows suit. In pallavi, the portion referred to above, the tani (thani) avariam portion is entirely percussion, since the melody-producing soloist turns to keeping the tala. For the most part, however, the Carnatic performance partnership is not a partnership in the sense of equal responsibility. Mridanga players in an accompanying role used to cultivate a more independent style of cross-rhythmical counterpoint with the soloist than they do today. The former style is used more often now with the veena.
The main role of an accompanist is to have a good and immediate grasp of the soloist's ideas and flawless repetition of the same. This does not imply that he merely echoes what the, but he has to lend support to what the soloist seeks to convey by connecting one idea to the next, by choosing a pitch register (unison or an octave above or below) that will emphasize or enhance tonal colour, by adjusting the playing style to reproduce the style of the solo melody, and so forth.
The hierarchical structure of the performance ensemble, whether Hindustani or Carnatic, is defined by the degree of freedom in the music making, and by that definition the soloist reigns supreme. The kind of support given to the soloist fosters a kind of competition among the members of the performance ensemble and contributes to that partnership. Significant tension is created in the process, in attempting to produce someone else's music, either a split second behind or after the phrase has ended, the contest between percussionists in tani avartam all contribute to lively and animated music making.
In improvisatory performance, it is the responsibility of each artist to balance the various musical elements. A soloist must develop melody to the best of his creative ability and must be equally at home with rhythmic exploration. He must pace the improvisation so that it remains imaginative, and must go on to something else when the imagination runs out. An improvisatory performance is basically a musical 'moment' that has never existed before and will never exist again in the same form. The shaping of a performance lies largely with the soloist and his is an enormous responsibility.
Thus, performance in Indian music involves a constant and complex interplay of elements. It is only when all the components are in order that the performance is complete.