Once a composition is started the duration of an aksharam has to be kept the
same. However, the music may have one note per aksharam, or 2 notes or 4
notes and so on thereby changing the duration of notes and making the music
appear faster. This aspect of Carnatic Music is called Kaalam. For lessons
up to the Geetham the first kaalam is sung with one note or swaram per
aksharam, the second kaalam with 2 notes per aksharam, the third with 4 notes
and so on. (A long note of double duration is counted as 2 notes.) You can listen to
pulses of 3 kaalams in Aadhi thaalam. Note that
the kriya or thaalam action is at the same speed for all the kaalams. Also listen to
notes of Maayaamaalavagowla in 2 kaalams.
Varnams are written with 4 notes per
aksharam and often when Varnam is sung in 2 kaalams, the 'first' kaalam is with
4 notes and 'second' kaalam is with 8 notes per aksharam. In writing notation for Kritis no uniform practice is
followed. You have to count the number of notes and find number of notes per aksharam.
Although no absolute duration for aksharams is prescribed normally they take
between .5 and 1.2 seconds. When aksharams are of longer duration the beats,
counts and waves may be repeated once to enable accuracy in time keeping.
This is called 'Two Kal(l)ai Chowkam', while the normal method is called 'one
Aadhi thaalam with 2 kalai may appear to have 16 aksharams as each
count is repeated once i.e. 2 beats, 6 counts, 2 beats, 2 waves, 2 beats and 2
waves. Listen to 2 kalai in Aadhi thaalam-the repetition of action is indicated
by change in color of the arrow which remains in the same position. The example (Vathapi Ganapathim)
in page 2 is in one kalai. 4 kalai chowkam (very slow) is sometimes used in Pallavis.