Complex sentence: Wu had a soft singing voice that made her a success, and a buzz later got around about a new singer, although Wu's father had not realized that it was his own daughter's voice that he heard on the radio.
Split into simpler sentences: Wu had a soft singing voice that made her a success, and a buzz later got around about a new singer. It was said that Wu's father at first didn't realize it was his own daughter's voice that he heard on the radio.