The venu[1] (Sanskrit: वेणु; vēṇu/मुरळि; muraļi) is one of the ancient transverse flutes of Indian classical music.
[5] The ancient Sanskrit texts of India describe other side blown flutes such as the murali and vamsika, but sometimes these terms are used interchangeably.
The flute is like the human voice in that it is monophonic and also has a typical two and half octave sound reproduction.
Sliding the fingers on and off the holes allows for production of variety of gamakas, important in the performance of raga-based music.
The flute (venu) finds great mention in Indian mythology and folklore having been listed as among the three original instruments meant for music along with the human voice and the veena (vaani-veena-venu).
In order to adapt the flute to Carnatic Music, certain modifications were necessary such as the addition of the 7th hole, usage of thicker walled bamboos, the technique of lifting the head to change the angle of embouchure when shifting between "ga" and "ma" notes.
Raw material preferred for making the South Indian venu is usually thicker and denser and grows in Kerala or southern Tamil Nadu.
There are also other varieties that are used, including bamboos that grow in the region of Sirsi, North Karnataka, Bihar.
Hence the usage of gamakas and andolans require a nimble hold and a way to bend the notes smoothly on a Venu.
Bansuri is more suited to Hindustani style of music due to its importance on long sustained notes and fast taans.
It is denoted either in numbers on a Venu from 1 to 7 with or without (1/2, indicating one semitone higher) or as per the standard Pitch letters on a Bansuri from A to G with or without (#-Sharps/b-Flats).
The Transition from Ga to Pa is an essential aspect which is to be practiced appropriately under the Guidance of a Flute Teacher.
Extreme strong blows allow the artist to even play few extra notes beyond the range the flute (some times leads to whistle sound).
Angling the flute against the blowing hole, allows the artist to modify and fine tune a note to the original pitch.
As a standard the black keys in a keyboard can be sounded in a flute with half finger closed on the corresponding hole.
This can be related to hard pressing the Veena string to get the bending/pitching note or using a Pitch Wheel in an Electronic/MIDI keyboard.