(This photo of a von Reumont type cello vibrator accompanied the book review by Joseph Curtin in the August 2000 Strad. Also shown is a newer Lehmann violin vibrator. Photos by Henry Strobel.)
This book remains the practical guide to "Vibration dedamping," which has been (like many areas of violin making) more art than science. The quantitative reduction in damping reported may contain errors of measurement and interpretation, but this does not exclude the possible benefits of the process, or of the book as a contribution to the art of violin making.
There is further scientific information in a paper by physicist Dr. Gottfried Lehmann. Part I was published in the German periodical Instrumentenbau-Zeitschrift of 9-10/2000. Part II appeared in the 11/12-2000 issue, including graphical data of measured response improvements after vibration. Part III appeared in the July/August issue 7/8-2001, and compared modal analyses before and after vibration treatment by the Lehmanns, father Dr. Gottfried, and son professional cellist Matthias, who built on the work of their friend and advisor, Prof. von Reumont, and were later assisted in their modal analysis measurements by Martin Schleske. Their conclusion also is that it can result in greater volume, easier response, richness of overtones, better bowing and more modulability. The specific physical changes in the instrument are still unclear, but are probably in areas such as glue joints, coatings, construction, repair and humidity induced stresses, and in particular the accelerated completion of creep, rather than in the character of the wood as such. (Disclaimer: I am speaking not as a scientist but as a publisher of books of interest to violin makers. I have tried "vibration dedamping" a number of times, some with noticeable improvements, some not. I have not used it commercially or routinely.)
The Lehmann paper, Experiences and Observations on the Effectiveness of a Procedure for Vibration Treatment of String Instruments, is not generally available in English, but Lothar Tews and I have translated it. All rights are reserved, copyright 2001, by Gottfried and Matthias Lehmann, and it may not be distributed or sold, but if you want to read a copy, Click here for the 8.2Mb download.
Perspective: Originally I was skeptical about the effects of "playing-in" an instrument, considering it mainly a hopeful belief of musicians buying and of dealers selling old instruments - those that "only needed a little playing-in." Like so many things in the world of the violin, of art and science, the objective and subjective may sometimes be resolved only with difficulty. There is general agreement among musicians that playing-in is real, and the "played-in" state of a violin is by definition its normal state for purposes of comparison or evaluation. The vibration dedamping treatment level far exceeds that of normal "playing-in," so we assume it does something. Subjective evaluation typically indicates an improvement well beyond mere suggestion, and vibration dedamping seems more effective than ordinary (low level) "playing-in". What about objective verification? There is the German Patent Office' investigation (J. Meyer, 1978), and the Lehmann paper. But the objective measurement of violin quality is not easy, and changes may be subtle, complex and variable from instrument to instrument and time to time. Care is also needed to exclude other effects, as of a soundpost inadvertently disturbed by the vibration.
Vibration dedamping as described can apparently improve some string instruments following original construction, storage or but light use, or major repair. It can make no further improvement in an instrument which is completely played-in, nor will it compensate for design errors, such as a too thick graduation. It is for use on complete, varnished instruments, not components. (The obvious cautions for possible equipment failure damaging the instrument apply.)
Note 1, Other Instruments: - While the emphasis has been on the bowed instruments, work has also been done with guitars, for example. See Instrumentenbau-Zeitschrift of 7-8/97, Neue Erkenntnisse beim Vibrationsentdaempfen von Gitarren, pages 31-38 and 44-47. Improvements in volume, sustain, rapid response, and tonal beauty are reported, and data are presented showing increases in output level and sustain.
Note 2, Hardware: This can be
fabricated from the detailed information in the book, but the
author and inventor may be able to supply some. Write to Prof.
Gerhard A. v. Reumont, K?lberweg 8, 58453 Witten 6,
A stroboscope may be useful to measure motor speed or to observe vibration amplitudes and wolf notes on the instrument. An inexpensive example (only up to 10,000 rpm or 167 Hz) is DT-2239A Digital Stroboscope, 115 VAC. See www.alfaelectronics.com?? (Henry Strobel has no financial interest in such sales.)