When the late legendary qawwali master Nusrat Fateh Ali Khan first sang in the United States, his concerts weren’t so different from those he performed in his native Pakistan.

With ecstatic and hypnotic improvised songs based in the ancient poetry of Sufism, the mystic tradition of Islam, Khan electrified audiences for up to five hours. He died in 1997 at the age of 49.

“We had to start cutting performances shorter for people who don’t understand the languages of the music (Farsi, Urdu and Punjabi),” said Rachid Din, who was Khan’s manager and now works with the next generation in Qawwali: Rizwan-Muazzam Qawwali.

The band, led by Khan’s nephews, is performing Wednesday night at the Kuumbwa Jazz Center.

“We don’t change the form of the Qawwali, for Western audiences but work with it so that, whether you understand the languages or not, it is interesting, animating and also carries the message.”

Now carrying the message forward from a family line five centuries long are the young Khans — Rizwan and Muazzam Ali Khan — one critic dubbed “the Qawwali Clash” for their raw intensity, fiery voices and rhythmic inventiveness.

The message of qawwali, like that of Sufism is universal and transformative peace and love. The word qawwali means “utterance.” That would be the utterance of divine power embodied by Sufism, the mystic tradition of Islam.

“With the music, especially the newest CD, ‘Day of Colors’ which is songs written 1,000 years ago, takes a look at what is the real message of Islam,” said Din, who speaks for the non-English speaking band.

“Though one man has given Islam a bad name, it was and still is about uniting people. The music has the power to do that.”

In concerts, that power is felt by audiences as a relief. According to Din, people report feeling lighter and more connected to those around them.

“The lyrics are written by Sufi saints, and whether you understand them or not, they have an effect on your heart,” said Din.

And likely on your body as well. The music, which originated in the early 10th century is a mix of Persian moqquams and Indian ragas : circular, polyrhythmic and trance-inducing.

The songs starts slow with call and response, and then gradually grow in intensity, sending the singers into wildly ornate lyrical and rhythmic improvisation — and listeners into unexpected realms. Some extreme forms of listener ecstasy have included the throwing of money and the banging of heads on walls.

Don’t even attempt sitting still while the Khans and their band of back-up singers, harmonium (reed organs similar to accordions) players and tabla player, hop, twitch and wail their way to ecstasy.

Those who have read the spiritual love songs of the Sufi mystic and poet Jelaluddin Rumi know that the words can easily be translated as addressed to god or to a lover. Same with Qawwali, which, in the hands of Khan’s grandfather emerged from its cloister in Sufi shrines into the secular world.

“The Khan family introduced qawwali music to social events,” said Din. “Now people from all walks of life hire qawwali singers for weddings.”

The virtuosity and romance of the devotional lyrics has made qawwali popular as background music in Indian films.

“When the music started 1,000 years ago, it had two purposes,” Din said. “One was to convey the message of Islam more effectively than with spoken word. The second was to praise god, which for the Sufi is to praise love.”

Like their uncle, who collaborated with musicians like Peter Gabriel and Eddie Vedder, the Khan boys have mixed it up with the high-tech band, Fun da Mental and producers, Temple of Sound.

“The idea of collaboration, with Nusrat as well as his nephews, is to widen the audience for qawwali,” Din said. “We are reaching younger audiences who then find out how very vibrant the music is, even when it is more traditional.”

There will never be another Nusrat Fateh Ali Khan — who rock critic Paul Williams called “the person Jerry Lee Lewis and Little Richard have always wanted to be” — and so his nephews carry a heavy load of history.

According to Din, youth is on their side.

“Nusrat will remain the only one,” he said. “But his nephews are like Nusrat in his youth. They are energetic and of all the people who learned from him, they have the closest flavor of his work.”