Different Taals with same number of matras

When we observe the various taals in Hindustani Classical Music, we notice that there are taals with same number of matras, similar vibhag, and khali tali but the bols are different. in the 16 Matra taals we have Teen Ttaal, Tilwada Taal , Adda Taal. In the 12 Matra Taals – Ek Taal, Char Taal. 

Hence the question arises as to why many taals of same matras are required. 

Indian music has always seen many changes throughout the history with each phase seeing new formats of music emerging.

With the development of Deshi sangeet which was for the enjoyment of people, Dhrupad-Dhamar was a popular form of music during the medieval times, when Khayal and Thumari did not exist. Dhrupad was a Gambhir form of music which involved loud vocalizing and instruments. Dhrupad was accompanied by the Gambhir sounding pakhwaj which had a set of taals meant for Dhrupad only. Taals of the pakhwaj were chartaal, tevra, sooltaal. 

Later on, with the influence of muslim rule in india, music forms such as Qawwali, Khayal Thumri became popular and the Tabla was used as the instrument for accompaniment. Pakhwaj was not suitable for the gentler sounding khayal. The bols of the tabla were much softer and suitable for khayal gayaki. The introduction of tabla and khayal gave rise to new taals like jhap Taal, teen Taal, ektaal, roopak. 

Similarly, when thumri was invented, the taals deepchandi and jat was introduced. Hence it is evident that with the evolution of geet forms, so did newer Taals were invented.

There are taals whose names are also forms of geet such as dadra, Dhamar, qawwali, Tappa which were used for the specific genres of music. 

The bols of the pakhwaj are very gambir and open in nature, whereas the bols of the tabla are soft. The layakari for the pakhwaj Taal is called thukda. The layakari forms of tabla are kayada-palta, peshkar, thukda.

Dhrupad music uses a lot of layakari whereas khayal music is swar Pradhan and madhur Pradhan, hence the bols of the Taal also reflect the same feeling.  

Hence the evolution of taals with same forms but different bols is out of the necessity of the geet it is supporting. 

Also Laya plays an important role in deciding the suitable Taal. Some taals are suitable only for Vilambit Laya and some for Ati-Drut Laya. Hence new Taals were developed for necessity to play or sing in different Laya. 

Taal also has the ability to generate Rasas such as Roudra, Gambhira, Shringar, Bhakti. Hence only suitable Taals are used to in the various forms of Geet which evoke similar Rasa.