this is the 2nd speed or kaala, which can hold half the number of swaras of the same speed as in 1st kaala if the taaLa is changed. Since the taaLa is held constant within a song, when one changes from madhyama kaala to durita kaala, double the number of swaras will be sung because they are sung faster. Thus if in first speed 4 swaras are sung per beat, in 2nd speed 8 swaras will be sung.