The effect of vibrato on response time in determining the pitch relationship of violin tones
This experiment investigates the effect of vibrato on response time in determining the pitch relationship of two successive violin tones. The result may provide insight into many musicians' impression that vibrato can be used to mask inaccurate intonation since the preliminary data indicate that listeners require more time to determine the pitch of a vibrato tone.
In our first experimental setup, based on previous research (Brown and Vaughn 1996), subjects were asked to compare two tones and determine if the second tone was higher or lower in pitch than the first. The first stimulus was either a vibrato tone or a non-vibrato tone and the second stimulus was always a non-vibrato tone. In the second setup, subjects were again asked to compare two tones and determine if the second tone was higher or lower in pitch than the first. This time, the order of stimuli was reversed: the first stimulus was always a non-vibrato tone and the second stimulus was either a vibrato tone or a non-vibrato tone.
The results from the first setup confirm the findings of the MIT study, that the choice of the first stimulus (vibrato or non-vibrato) does not significantly affect subjects' ability to compare the stimuli. In order to more accurately preserve the timbral change corresponding to a changing pitch on the violin, we carefully recorded a violin at different pitches from -15 to +21 cents from the mean, rather than resampling one recorded pitch as was the case of the MIT study. This modification, however, did not significantly alter the results of the pitch comparison task.
We compared the response times in the first setup, and found no appreciable differences based on the choice of the first stimulus. However, in comparing the response times from the second setup, we found that subjects took longer when the second tone was a vibrato tone. This may explain the commonly held belief among musicians that vibrato can be used to mask poor intonation.