Terence Tow, who founded UntapTV with his Cambridge University friend Tee Vachiramon, said concert-goers had liked the technology at a test event with the band Maroon 5 at the Mercedes-Benz Arena in Shanghai.

"In a concert you can start receiving information about the warm-up band, lyrics, in-concert voting," he said in an interview. He said the night they tested it each person opened the app 10 times on average and spent 12 minutes using it.

Tow said he chose audio for his start-up because it could be used more widely than visual codes, such as bar codes or QR (quick response) codes, which are read by smartphone cameras.

"We call it a sonic response code, it's like a QR code, but in sound," he said.

The codes, which last for a few seconds, cannot be heard by the human ear, so they can be transmitted while music is playing, within broadcasts or in places such as shops, he said.

The technology is also quicker than other types of audio recognition, like the popular Shazam app, which can identify songs from a 10-second music clip.

The audio codes are robust enough to be included in YouTube videos, Tow said, and the technology has been tested by BBC Worldwide in broadcasts carried by satellite.

UntapTV, based in the 'Silicon Roundabout' district of east London, has signed a partnership with music events group AEG Live to provide content in its arenas in Shanghai and Beijing.

The live music events firm said it would use UntapTV's technology at its events, including Elton John concerts next month.

(Editing by Jane Merriman)

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