Andy Piacsek – andy.piacsek@cwu.edu
Central Washington University
Department of Physics
Ellensburg, WA 98926
United States
Seth Lowery
Ph.D. candidate, University of Texas
Dept. of Mechanical Engineering
Austin, TX
Popular version of 4pMU3 – An experiment to measure changes in violin instrument response due to playing-in
Presented at the 185th ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0023547
Please keep in mind that the research described in this Lay Language Paper may not have yet been peer reviewed.
How is a violin like a pair of hiking boots? Many violinists would respond “They both improve with use.” Just as boots need to be “broken in” by being worn several times to make them more supple, many musicians believe that a new violin, cello, or guitar, needs to be “played in” for a period of time, typically months, in order to fully develop its acoustic properties. There is even a commercial product, the Tone-Rite, that is marketed as a way to accelerate the playing-in process, with the claim of dramatically increasing “resonance, balance, and range,” and some builders of stringed instruments, known as luthiers, provide a service of pre-playing-in their instruments, using their own methods of mechanical stimulus, prior to selling them. But do we know if violins actually improve with use?
We tested the hypothesis that putting vibrational energy into a violin will, over time, change how the violin body responds to the vibration of the strings, which is measured as the frequency response. We used three violins in our experiment: one was left alone, serving as a control, while the two test violins were “played” by applying mechanical vibrations directly to the bridge. One of the mechanical sources was the Tone Rite, the other was a shaker driven with a signal created from a Vivaldi violin concerto as shown in the video below. The total time of vibration exceeded 1600 hours, equivalent to ten months of being played six hours per day.
Approximately once per week, we measured the frequency response of all three violins using two standard methods: bridge admittance, which characterizes the vibration of the violin body, and acoustic radiativity, which is based on the sound radiated by the violin. The measurement set up is illustrated in Figure 1.
Figure 1: Measuring the frequency response of a violin in an anechoic chamber.
Figure 1: Measuring the frequency response of a violin in an anechoic chamber.Having a control violin allowed us to account for factors not associated with playing-in, such as fluctuating environmental conditions or simple aging, that might affect the frequency response. If mechanical vibrations had the hypothesized effect of physically altering the violin body, such as creating microcracks in the wood, glue, or varnish, and if the result were an increase in “resonance, balance, and range”, then we would expect a noticeable and cumulative change in the frequency response of the test violins compared to the control violin.
We did not observe any changes in the frequency responses of the violins that correlate with the amount of vibration. In Figure 2a, we plot a normalized difference in the bridge admittance between the two test violins and the control violin; Figure 2b shows a similar plot for the acoustic radiativity.
In both plots, we see no evidence that the difference between the test violins and the control violin increases with more vibration; instead we see random fluctuations that can be attributed to the slightly different experimental conditions of each measurement. This applies to both the Tone-Rite, which vibrates primarily with the 60 Hz frequency of the electric power it is plugged into, and the shaker, which provided the same frequencies that a violinist practicing her instrument would create.
Our conclusion is that long term vibrational stimulus of a violin, whether achieved mechanically or by actual playing, does not produce a physical change in the violin body that could affect its tonal characteristics.