Changba's celebrity users get together for a singing party. [Photo provided to China Daily]

Many of those who use the app will have been influenced by acquaintances who use it, he says.

As long as you have talent you can build up a fan base through the app and even become well known, he says, even without having to take part in a singing contest on TV.

"As a singing platform, the app helps independent musicians get their original works known and improves their incomes so they can make ends meet."

Some live stream their singing and sing or chat with fans. Their income is subject to how many virtual gifts they receive from fans.

For Liu Xingtong, 36, a mobile karaoke app is a good substitute for a karaoke bar.

"The thing about the app is that I can sing with it whenever I want," says Liu, an office worker of Guangzhou. "Now rather than going out with friends all I want to do is sing with all my heart. It's a bit of a difficult situation because I know that if I were in a karaoke bar with them some would be singing out of tune."

She used to frequent karaoke bars when she was a teenager.

"It was the golden age of karaoke. Without the internet, reality shows or social media, karaoke was almost the only way for young people to have fun."

Liu says she used to pay to record her singing in a karaoke bar but can now do so free with the app. She also likes to hear others sing.

However, for some like Yang, a mobile app cannot replace the experience of singing in a karaoke bar.

She likes spending time with her friends in a bar because of the relaxed atmosphere and good equipment such as stereo sound effects. They often choose a place that serves food, and a good time is had by all, she says.

"It's different having someone right by your side enjoying you singing rather than receiving a 'like' online. The other thing is that when I'm at home using the app it bothers me that my parents may interrupt. In a karaoke room there are no such worries.".

In June 2014 Changba joined with Beijing Mysong Culture Communication Co Ltd to establish Changba Mysong KTV, with more than 70 chained karaoke bars in 15 provinces and cities. One store has 15 to 30 rooms, the idea being to maximize use and minimize overheads.