Patrick Gaydecki, professor of digital signal processing, told The Guardian that the distinctive violin sound comes from the body of the instrument, not the strings, which [given the same material] sound practically the same on any violin.
"The violin is like a bell or any resonant system. It vibrates with a characteristic signature," he told the paper. To extract this "signature," the researchers zap the instrument with a laser pulse and then record the vibrations.
The new Sound Wizard system developed by the Manchester University team can separate the sound of the string from the full violin sound and "then give it the amplification provided by the body of a Stradivarius," according to The Guardian.
The Sound Wizard can also clean up recordings with background noise or LPs with scratches and improve the output from loudspeakers, according to the paper.