Today, I'm joined in the studio by some very special guests to talk about the a cappella phenomenon. We're going to come back and talk about a capella in a short while, but before that, the Meet in Beijing Arts Festival in the Chinese capital has embraced one of the most popular a cappella groups in the world, the Swingle Singers. Our reporter Qi Jie takes us to the Beijing Concert Hall to get a TASTE of the legendary Swingles and the audience's reactions.

It's said that the most beautiful sound on the planet is the human voice. And human voices sound most beautiful when in harmony. Here in Beijing, the Swingle Singers have brought us the harmony, known as A Cappella.

Despite a tight schedule and a long journey, the tired Swingles aren't allowing any details to be overlooked in the rehearsal.

QI JIE BEIJING "Soprano, alto, tenor and bass, when they come together, it's 'the sound of nature' on humankind's original musical instrument. It's an incredible journey that the Swingles have explored for decades."

And they'll never let the audience down, GREAT audiences in particular.

ZHANG HONGYU AUDIENCE MEMBER "I hope China will invite more and more artists like them to come, and also cultivate more prestigious Chinese musicians whom Chinese people are crazy about."

Starting in Medieval church choirs, and surviving through the Renaissance to the 21st century, a cappella singing has experienced enlightenment, decline and rejuvenation. Before we find out why it's popular again today, let's hear what the harmony sounds like.

GENG YUTING AUDIENCE MEMBER "A cappella singing brings you back to nature. Today, most young people are under great pressure. Getting a chance to listen to a cappella music on the weekend, is so touching. Inexplicably. I guess that's the love from the bottom of my heart."

In China, there's an old saying about music, saying "silk is not as good as bamboo. Bamboo is inferior to meat". It means that it's better to play wind instruments than to play a string. And compared to playing wind instruments, it's better to sing out loud.

LI YAFEI AUDIENCE MEMBER "I work in the music industry. It's terrific to have the opportunity to listen to a cappella live. A choir accompanied by different music imitated by mouths, it's GORGEOUS! The sound of nature is indeed much better than any kind of instruments."

With five Grammys under their belts in over half a century, the Swingle Singers are no historical legend, they're a sensation. QIJIE, CGTN, BEIJING