Sound of the conch shell is made to mark auspicious occasions and is known as Shankadhwani or uludhvani or ududhwani. Conch and the sound of conch shell is an important object in a Hindu home and it suggests the prosperity of a home.
Every evening a member of the house blow the conch to offer prayer to the presiding household deity. In some Hindu homes, the shankha has as much a place of reverence as that of an image of Goddess Lakshmi.
All pujas are also incomplete without the sound of a conch shell. Should a new child be born in the family, the blowing of conch shells announces its birth. During nuptial ceremonies, conch shells are blown vigorously to welcome the groom or the bride. On occasions like annaprashna (first cereal eating ceremony of child), upanayana (thread ceremony), and most of the rituals, conch of sound is a must.
The importance of conch sound dates back to the Puranas. In the Mahabharata, we read about different conches of the Pandavas and other warriors. The most famous Shankha, called Panchajanya, is that of Sri Krishna.
Nowadays, conch shells are blown only on religious and other happy events. However, in the past, conch shells used to be blown in musical events also. It is heard that, in old times, Bengali musical events consisted of Shankataranga, in which seven or twelve shankas of different tones were blown in different ragas (melodies).
Uludhvani or ududhvani is a type of sound made by women in Bengal to announce good news. It is made after childbirth, during marriage, and in rituals related to some pujas.