They are tools for transformation, to transform our ordinary being into a higher realm of the Buddha nature. The sounds of these instruments are unlike any other instrument in the world. Quite an incredible quality. "not only affects the person who's using it, but also it affects all of the surrounding area.
Actually, the sound carries very far even when we can't physically hear it. When we play the tingshaw all spirits, hungry ghosts are coming thousands of kilometres away, they can hear this sound, coming saying 'Oh, something's there!'. So, the sound is incredible. who has seeds they are, immediately they get teaching. So same way if you are ringing the singing bowl, if you didn't get teaching, but someone get teaching. So, why we made those singing bowls, why we make a bell, and cymbals, drums, conch, why you know? Each thing giving different teachings. Also, conch gives you lot of big voice giving. Conch sound is only for Dharma using, you know. For calling monks, or making pujas. So, we call that Dharma chakra, sound of conch.
In the tradition of Buddhism even from the very beginning, from the first teaching of Buddha, there is that tradition of using sound in connection with teaching.