Complex sentence: Lauri-Volpi's voice was bright, flexible and ringing in tone, with a characteristic shimmering vibrato and astonishing high notes that he kept to the end of his career.
Split into simpler sentences: Lauri-Volpi's voice was bright, flexible and ringing in tone. It was characterised by a shimmering vibrato and astonishing high notes that he kept to the end of his career.