Improvisation still continues in this phase. The text sung is usually different from the baRaa khayaal. The characteristic of this part of the performance is the contant acceleration and inclusion of a lot more taans, and repetition of the mukhRaa of the sthaa'ee. Some singers substitute taraanaa for chhoTaa khayaal during the performance. The characteristic is the syllable ta occurs on count 1 of the taal.
Some people say that the vocables of a taraanaa are words of mystic poetry.
Taala teentaal, tilvaaRaa taal, jhaptaal, jhoomraa taal, ektaal are the commonly used talas in a baRaa khayaal performance. A typical live performance lasts about 30-45 minutes. There are a number of gharanas associated with this genre of music and the artistes are too numerous to name here. The gharana list posted on SCI should be of some use. Thumree Thumree originated from Lucknow and Benares in the 19th century.