The origin of Carnatic music, or the South Indian classical music can be traced back to the age of vedas. Bharata's Natya Sastra from around the 5th century A.D., and Saranga Deva's Sangita Ratnakara, from the early 13th century A.D., are considered the to be the earliest recorded documents available on the theory and performance of Indian classical music.
The history of Carnatic music is incomplete without stating about the contributions made by the saints Sri Purandharadasaru (15th century A.D.), Sri Thyagarajar, Sri Shyama Sastri (all of 18th century A.D.), and left an enduring legacy of compositions. This tradition has a rich heritage and is perfectly attuned with Indian culture and religion.
Carnatic music is based on a 22 scale note (swaras) on contrary to the earlier 12 note scale that is used in the western classical music. But in all its practical aspects and puposes, not more than 16 notes are generally used. A unique combination of these notes, or swara as they are said to evolves separate ragas.
The features and the constraints of a raga will be clearly defined in the arrangement of the notes in its arohanam (ascending notes) and avarohanam (descending notes). Thus, in Carnatic music, the raga connotes a mood or a route in which the music is supposed to travel.
Different combinations of the notes gives rise to different raga. Thus, there are thousands of unique raga as per theory though very few of them are being used for performances in the present day. Gamaka and brighaa are the two most important features of the ragaa. The former refers to the modulation of the frequency of a particular swara and the latter refers to the speed with which the musician performs a set of swaras or notes.
Both the gamaka and the brigha helps to improve the appeal of the composition that is rendered. Western music is often based on a pattern of flat notes, on the contrary, here, the swaras are performed using various modulations.
The brigha could be often 8, 16 or so on. Another very important aspect of the Carnatic music is the thalam or the rhythm. The thalam is the rhythm of the piece that is being performed. Today, there exists more than hundred thalams, but here also, very few of them are in use. The most popular thalam have three, four, five, seven or eight beats in them.