Talas in Dhrupad form the very basis of the music. It is the very rhythm of music without which no music would have any form. Each cycle of the Tala is called Avarta. The beginning of an Avarta is called Sama. The Sama is indicated by a stronger than usual percussion of the drum. The singer also indicates this point by a louder and stressed singing of the syllable denoting the Sama. The singer and the player are both required to arrive at the point of Sama simultaneously but within the cycle both are allowed a fair degree of freedom in subdividing this period in order to display their art.
Each cycle or Avarta of Tala is divided into a number of equal parts called Matras whose number differs from Tala to Tala. Each Tala has a fixed number of Matras. In different Talas the number of Matras varies from one to twenty-eight or more. Among the Talas in modern times the smallest number of Matra is six and the largest number of Matras is twenty-eight. The most common number of Matras in a Tala ranges form six to sixteen. The characteristic thing about the Talas is that though these Matras represent equal divisions of a cycle, all of these are not necessarily equally emphasized. Some of the Matras and sometimes even half-Matras are picked for emphasis which is demonstrated either by a forceful percussion on the drum or by no percussion at all. Sometimes instead of no percussion the drummer plays an extremely light one. The divisions of Avarta are called Vibhagas. A Vibhaga is a group of Matras. The number of Matras in different Vibhagas of the same Avarta may be equal or unequal. A Tala is identified by the number of Matras in each Avarta and by the ordinal number of the Matras that are to be emphasized. The duration of each Matra is indicated by Bolas. In Talas a certain degree of variation is permitted within the basic framework in order to create and enrich variety. Each Tala thus has a basic rhythm and an ornamented rhythm.
In earlier times large number of Talas was used in Dhrupad. Their names are mentioned in Sahasarasa - a collection of one thousand Dhrupads of Baksu. These Talas are- Ekatali, Adatdla, Samatala, Jhumaratala, Kamalamanthatsla, Talagana or Jatalaganatala, Chaturthatala, Jhapatala or Jhampa, Tritiya Tala and Parata Tala. Out of all these Talas, Jhapatala is the only one in which Dhrupads are sung even today although the character of Jhapatala is now different from what it was before. Sahasarasa merely mentions the names of these Talas but unfortunately does not describe them. Over the course of time the Talas have been subject to much change and modification. The Talas, that have come down to and in which the Dhrupads are sung today are Chautala Jhapatala, Sulatala, Suraphakhtatala and Gajajhampatala. Chautala and Jhapatala are the most popular ones and most Dhrupads are sung in these Talas. Even among these, the Chautala is by far the commonest and has become identified with Dhrupad.
There are many Dhrupad compilations where the Tala in which the song has to be sung is not written. There are also many others where the Tala has been mentioned but those Talas have been long forgotten. Thus the modern Dhrupad players are not left with much choice but to sing them in Talas which are prevalent these days and which they know. It is therefore not unusual for a Dhrupad which is mentioned in Sahasarasa as being in Kamalamanthatala to be sung today in Chautala or Jhapatala. Thus the Dhrupads, which in earlier times, would have been sung in medieval Talas, are sung today in above mentioned Talas.
