Sylvia Hallett studied music at Dartington College, following this with two years in Paris studying composition, and since the 1970s composition and improvisation have been the two parallel planks of her career.

As a performer she initially concentrated on the violin, but has since extended her practice into a range of other plucked and bowed instruments such as the harp, the Indian sarangi, the musical saw, and - most unlikely of all - the bicycle wheel. She is a regular member of the London Improvisers Orchestra, and works in many smaller combinations with such leading artists as Evan Parker, Lol Coxhill and Phil Minton. She is also a highly respected composer and performer of incidental music for radio and stage, with work for the BBC and for the Young Vic and the Royal Shakespeare Company.