Quality of Violin Vibrato Tones

Typical violin tones with vibrato were recorded on magnetic tape. From a special analysis, synthetic tones were constructed that were very difficult to distinguish from real tones. The analysis showed that not only the frequency was varying up and down about sit times per second, but there were three other important characteristics varying at this same rate. All of the harmonics had the same variation of the frequency level, in cents, from the note being played. There was also an intensity-level variation of the harmonics at the same vibrato rate, but the intensity-level variation was greatly different for different harmonics. Also, the intensity of some of the harmonics would be rising while that of others would be falling during the vibrato period. Thus, a curve showing the relative intensity level of the harmonics at any instant changed back and forth during the vibrato cycle. The intensities of the sympathetic tone coming from the open strings also varied either at the vibrato rate or twice the vibrato rate, while the frequencies of these tones remain constant and correspond to the natural frequencies of the fundamental and harmonics of the open strings. The after-ring is due principally to these transient tones. This effect is negligible when the frequencies of the fundamental and its harmonics are not close to those of the open string.