"Usually Asian students are stereotyped as xue ba, which means nerdy best academic performers. We made jokes with the name - but we are definitely not just good at studies but we are also versatile," says the 23-year-old Chen, a Zhengzhou native who now works at a French luxury product company in Shanghai.

Chen, who has studied piano and classical guitar since she was a child, first saw a male a cappella group performing Lady Gaga's Poker Face online before she went to study in the United States.

"When I went to the university, I found that there are more than 10 a cappella groups and I liked watching their showcases in the campus," she says.

He Zhiyao, another member of Calculasion, who spent a year at Berkeley in an exchange program and has now returned to study at Beijing's Renmin University of China, says that most of the members have their own jobs now, with some working in Silicon Valley while some further their studies.

"Calculasian is not a very productive group but we take it seriously, not just as a hobby but also as a career," says the Beijing native, 22. "Though it's hard for us to gather together regularly, we still want to make high-quality music and make it last."