Basically, originally, music was used for meditation; particularly Indian music developed as a method of meditation, Indian dancing developed as a method of meditation. For the doer it was a deep meditation, and for the audience also it was a deep meditation. A dancer or a musician can be a technician. If there is no meditation in it, he is a technician. He can be a great technician, but then the soul is not there, only the body. The soul comes only when the musician is a deep meditator.
And music is just the outward thing. While playing on his sitar, one is not only playing on his sitar, he is also playing on his alertness inside. The sitar goes on outwardly and his intense awareness moves inside. The music flows outwardly, but he is alert, constantly aware of the innermost core of it. And that gives samadhi. That becomes ecstasy. That becomes the highest peak.
Osho | The Book of Secrets: 112 Meditations to Discover the Mystery Within