Naad (Sound) :
This is sound produced by striking, friction or beating. 'Naad' is of two kinds:
(a) Sangeet-un-upyogi Naad (Non-Musical sound): Those sounds which are not musical such as machine rattlings, traffic horns, shouting etc. These sounds are not pleasant to listen to and are disturbing in nature. They can cause headaches and irritation. We hear these sounds in our day-to-day lives in the city.
(b) Sangeet-upyogi Naad (Musical sound): Contrary to non-musical sounds, these sounds are pleasant to listen to and musically audible. These can be the sounds of nature as the chirping of birds, water falls, flowing river, singing etc. These sounds are relaxing and give a feeling of tranquility and peace. Musical sounds like singing and instrumental playing have the virtue to hypnotize an audience.