Bulgarian singer Smilyana Zaharieva performs during an interview.

Smilyana Zaharieva knew she had a gift when she saw her audience tremble or cry during her performances.

Now an official Guinness world record confirms that the Bulgarian singer has one of the most powerful voices on the planet, which can stay pitch perfect despite being as loud as a rock concert.

"When I saw the monitor reading 113.8 decibels, it surprised me," the 48-year-old told AFP of her record-setting attempt last September.

Tough requirements

Irish teacher Annalisa Flanagan holds the world's loudest shouting record with 121 decibels (dB), but there was no previous singing record.

The lively Bulgarian from the southern city of Plovdiv faced a series of tough requirements.

Zaharieva had to sing in a quiet studio and go over 110 dB, the average human discomfort threshold, with the sound meter placed 2.5 metres (8.2 feet) away from her while also holding the note for a minimum of five seconds.

'Exceptional register '

As a child, Zaharieva studied folk singing in the National School of Folklore Art in the Rhodope mountains in southern Bulgaria before pursuing a degree from the Plovdiv Conservatory of Music.

For several years she was part of another women's choir, The Great Voices of Bulgaria, touring the world.

"When I sang people would tremble or cry," she said.

Bulgarian singer Smilyana Zaharieva shows her Guinness certificate.

Madonna as collaborator?

Keen on yoga and interested in Eastern meditation techniques, Zaharieva wants to explore the curative effects of sound and is seeking to collaborate with other artists. She has already asked American pop-star Madonna.

"This voice that has been given to me, I want to use it to help people and find a message to convey," said the mother-of-two and recent grandmother of twins.

"Each sound corresponds to an energy centre in the body and to an organ," the singer explains, adding various combinations of sound can cure illnesses.

Agence France-Presse