The late Ariyakudi Ramanuja Iyengar, a veteran Carnatic music vocalist, is credited with establishing the contemporary concert format which has been in use by Carnatic musicians to this day.
A contemporary Carnatic concert (called a katcheri) usually lasts about three hours, and usually comprises a number of varied compositions. Carnatic songs are composed in a particular raga, which means that they do not deviate from the notes in the raga. Each composition is set with specific notes and beats, but performers improvise extensively. Improvisation occurs in the melody of the composition as well as in using the notes to expound the beauty of the raga