De-damping is the study of mechanically exciting the instrument’s structure to stimulate the elasticity of the wood with the goal of accelerating the break-in and aging process. The effect is much like constantly flexing a wooden coffee stirrer; the more the stirrer is flexed, the more limber the wood becomes.
De-damping is not new; it is an age-old process handed down through early viol-family instrument development, and much as been written about the subject. Most musicians know that their instrument sounds better after they have had a chance to warm it up a bit — in essence, the result of short-term de-damping.
In October 2007, we modified our de-damping service to a 24/48/8/8/8 program that now consists of: 24 hours of continuous mechanical strumming, 48 hours of mechanical agitation (Lehmann process), 8 hours of continuous external excitation of the backboard, 8 hours continuous excitation of the air chamber, and 8 hours continuous external excitation of the soundboard.
During the mechanical excitation, the strings are mechanically strummed (continuously) for 24 hours with dB readings taken at regular intervals to monitor the progress.
Borrowing from the Lehmann method, we mechanically agitate the soundboard via an oscillating motor connected to the bridge and set to an oscillation frequency that equals the resonant frequency of the soundboard (20 hrs), backboard (20 hrs), and air chamber (8 hours).
Then, intense sound energy is directed towards the instrument via a directional speaker at 90 dB causing the instrument to respond and vibrate through sympathetic vibrations. Three different frequencies are used; the resonant frequency of the backboard, the soundboard, and the air chamber.
The combination of direct and indirect excitation has a profound effect on flexing the structure of the instrument, altering the elasticity of the wood and finish, and improving the instrument’s amplitude, clarity, sustain, and timbre.
Our fixtures are adjustable to all instrument formats, from fiddles to acoustic guitars. Here, an H4 mandola is undergoing the mechanical excitation process.
For fiddles, we use the oscillating motor for 72 hours and do not apply mechanical excitation. The instrument will still receive external excitation from the directional speaker.
We asked a few customers to provide us with their honest appraisal of our de-damping service. Here’s what they said:
My once powerful Dawg mandolin had become muffled and incredibly non-vibrant over time and following repeated attempts to rejuvenate it, it was suggested that I utilize Mr. Siminoff’s de-damping process as it had helped rejuvenate a friend’s mandolin greatly. I sent it for de-damping and I can honestly say what transpired was miraculous and this mandolin has not sounded nearly this good in every way for many years. I am overjoyed and totally satisfied. • Dr. Gary Smith, Groton, CT
Several years ago, I purchased a relatively new Weber mandolin. It was to be my back-up mandolin. The previous owner did not play it much, nor did I, and most people agreed it needed to be broken in before it’s true nature could be determined. I started to play it more frequently in an effort to loosen it up, but it seemed to be slow going. That’s when I heard about the de-damping process. The effects were immediately apparent to everyone who had heard it before and after. Adding a new set of strings made it even more evident … the de-damping process had broken in this new mandolin in a matter of days. • Phil Cornish, San Jose, CA
I heard Roger had been working on experiments with breaking-in mandolins, and had read about this process being done, mostly in violin world, and in Europe. My vintage instruments have a more open sound, and I was looking for improvement in that area. I also had two others that I thought sounded good, but some of the strings were so good they made the others seem to be weak in comparison. I am pleased to report that one instrument from each category came back greatly improved. One, a Gilchrist Artist Model 3A, had a beautiful voice, but just seemed tight. After the first round I heard some improvement, but still felt there was more, so I sent it back to Roger for a second round of dedamping, and it is now transformed into a stellar instrument. Now it is one of my favorite mandolins, and is so much more fun to play. Another F5 built by Michael Heiden was special right from new, but the bass was so good the top end seemed slightly out of balance. It benefited greatly from the dedamping process, is now much more in balance, and the top end has come alive. Two other instruments only showed a more modest improvement, so results do vary, but two showed very positive results, and are now balanced across the strings, with a more open and clear voice. I am very pleased with the service Mr. Siminoff is offering, and would certainly recommend it as an experiment, especially before giving up on a mandolin that might seem too tight sonically. • Arthur Stern, Benicia, CA
• Siminoff 72/8/8/8 de-damping service; includes report of resonant frequencies of backboard, treble tone bar, bass tone bar, and air chamber along with dB measurements during the mechanical excitation process. $125.00
• Re-packaging of your mandolin (we will try to re-use your shipping carton if it is still intact). $10.00. Re-packaging of a guitar is $15.00
• Shipping cost: based on weight of your package and your location.
• Processing time: We need the instrument for about 10 days, but please call ahead to schedule when it should arrive.
• More information: Do not hesitate to call or write if you would like more information on our De-damping Service.
• Selected reading: If you are interested in learning more about de-damping, you might enjoy looking at these two documents:
Artificial aging by vibratory means, Gottfried Lehmann, Experiences and Observations on the Effectiveness of a Procedure for Vibration Treatment of String Instruments. http://www.henrystrobel.com/lehmann.pdf
A means for inhibiting the damping qualities of an instrument, von Reumont, De-damping Process. http://www.henrystrobel.com/vibrate.htm
If you are interested in learning more about how others do mechanical de-damping for violin family instruments, please see http://www.violin-reverb.de/violin/dedamping.htm
1) Not all mandolins de-damp at the same rate; some show better results than others depending on instrument’s age, thickness of soundboard and backboard, initial tuning (if any), thickness and type of finish, and construction methods.
2) As the finish flexes during the de-damping process, grain lines might become more evident in the finish (as it appears on older instruments).
3) The de-damping process is intense and continuous, but not abusive.
4) De-damping accelerates but does not replace or interfere with the normal aging process. (While flexing the wood makes the fibers and cells more limber, it does not replace the polymerization that occurs in wood during normal aging.)
5) Unlike the results from brief warm-up periods that most musicians experience with their instruments, the de-damping process is permanent.
6) We are continuously developing and improving this process. In October 2007, we changed our 72/8/8/8 service to include 48 hours of mechanical agitation using the Lehmann process with excellent results.
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