The vibrato technique used in violin and human voice performance improves the musical consonance of the resultant sound wave by causing a continous ripple in the intonation of a musical interval about its nominal value. Music is essentially critically unstable digitally processed information controlled by a musical beat that is always present when sound waves interact. It also explains why multi string instruments like 12 string guitars and triple stringed musical notes on a piano sound so good.
John Winter winterjr@tiscali.co.uk