By the end of the 11th century there arose the tradition of the sama.  The sama was often a spiritual concert, which included a vocalist, and instrumentalists.  These samas took place under the direction of a spiritually respected man (shaikh).  

 There is a very specific psychological process which a qawwāli follows.  One starts with the singing of the song.  In this psychological state the song is received in a manner that is not unlike standard forms of musical expression.  The words are sung, quite repeatedly with variations intended to bring out deeper means of the lyrics.  After awhile there is a repetition to the extent that the words cease to have a meaning; It is the goal here to lead the listener and performer alike into a trance (hal).  In the ideal situation the participant is moved to a state of spiritual enlightenment (fana).  

 History of Qawwali

The origins of qawwāli probably predate the birth of Muhammad.  The earliest Islamic scholars discussed the spiritual effects of music, but it was only in the time of al-Gazali(1085-1111) that these principles were refined and codified.  These principles were then expanded by the Chisti school of Sufism.  It is this order that has been responsible for the propagation of the qawwāli in India and Pakistan for then last few centuries