Asif Ali Khan & Party features a chorus of 10 people from Pakistan who are all members of the same family. However, they don't see themselves as simply singing; rather they are listening to "God's instructions with our souls," in their own words. They believe their performances are a way of connecting themselves with God in a spiritual way while on stage.

The group's style of singing and performing is known as "Qawwali" which refers to a Sufi devotional music tradition popular in India and Pakistan, especially in the Punjab and Sindh regions of Pakistan and Hyderabad, and Delhi in India. In the 11th century, the first wave of Persian migrants travelled to South Asia and established the roots of Qawwali there.

The word "Qawwali" is derived from the Arabic word, "Qaol," which means axiom or dictum. Qawwali is generally regarded as the sayings of the prophets in the praise of God.

In our blood

"I can't imagine a day in our life without Qawwali; it's in our blood," said lead vocalist Asif Ali Khan (pictured right) after whom the group is named.

Among the other nine members of the group are Khan's father, brothers and several of his cousins.

During the World Music Shanghai 2012 from April 28 to May 6, the group was invited to perform Qawwali for the first time ever in the city.

Raza Hussain, Khan's brother, told the Global Times that a group of Qawwali musicians, usually called a "party," typically consists of between eight and 10 people. The traditional instruments used in Qawwali, include the harmonium (a traditional Indian wooden keyboard) and the tabla (a popular Indian percussion instrument). The performers usually sit cross-legged on the ground in two rows with several singers, including the lead, and the harmonium player in the front row.

The other singers and the percussionists sit in the back row and occasionally contribute hand clapping to the performance.

"Two harmoniums and one tabla is the standard layout for a Qawwali party and the lead singer usually doesn't sit in the middle of the group, but at the side," said Hussain. "The lyrics of Qawwali music all originate from ancient poems written by Sufi poets several centuries ago. The themes are usually about divine love, and a 'oneness' with God. They express the fullness of love between God and man."

Khan's family comes from Lahore, the capital of Punjab, and the type of Qawwali they perform is also known as the Punjabi Ang. It has several distinctive features, including rich vocalizations, vigorous rhythms provided by percussion instruments and hand clapping, and other effects such as a sudden silence introduced at the height of one of the musical phrases, or a particularly soft reprise straight after an emotional outpouring of music and voices.

The French-born agent for the group, Wowkonowicz Snafu, told the Global Times that Asif Ali Khan's family comprises a distinguished dynasty of professional Qawwali musicians that stretches back 350 years.

Hussain added: "Our great-grandfather, Maula Backsh Khan was a Qawwali musician, but he just played it in his spare time, and he transmitted the Qawwali tradition to my grandfather, Santoo Khan. He started our family as Qawwali professionals, and since then, my father and now, our generation have all become involved. We all started to learn Qawwali when we were just children."

Asif Ali Khan is the youngest of the brothers and was born in 1973. He joined the group at the age of 14, where he quickly displayed outstanding vocal qualities, including impeccable diction, brilliant inventiveness and a genuine-sounding sincerity placed in the service of Sufism.

And it was precisely these qualities that brought Asif Ali Khan to the attention of Nusrat Feteh Ali Khan (1948-1997, the world-renowned musician who is widely referred as "the Emperor of Qawwali"). After observing Asif Ali Khan's progress over several years, the master decided to take him under his wing in 1995.