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Liquid deposition modeling is an energy-efficient, additive manufacturing process for pasty materials. Physical material properties were determined for a water-based paste consisting of the binder carboxymethyl cellulose and wood flour. A continuously operating dual screw extruder was developed, which was used to manufacture a table frame with a height of 18 cm.
Natural varnishes have been used for centuries by musical instrument makers to protect the instruments for climatic, aesthetic and acoustic reasons. The effects of varnishes on the protection of the wood surface, as well as their aesthetic parameters, are easier to verify and compare visually, but the comparison of their acoustic effects has always been challenging and debated.
In fact, varnish layers have a small effect on the vibration properties of wood. For example, the effect of a decrease or increase in humidity on the vibration properties of wood is sometimes equal to the effect of several layers of varnish. Because of this small amount of effect, measuring this effect is also difficult and challenging.
Our strategy in this study is to obtain the clearest possible results by comparing the effect of only two types of oil varnishes with completely opposite elastomechanical properties and increasing the number of samples varnished.
The samples were measured before and after each varnish layer using conventional methods for measuring vibration properties, and the average results of the same samples were discussed and analyzed.
Overall, the amber varnish obviously has a more negative effect on the vibration properties of the violin plates compared to the colophony varnish.
Finite element Analysis is a powerful tool that enables a thorough examination of the physical and mechanical aspects of various objects, yielding insights that would otherwise be difficult to obtain. In the context of the guitar industry, this technology can be used to determine the role of internal bracing structures with a high degree of precision. Specifically, FEM is commonly utilized to analyze the natural vibration frequency of guitars and to gain a better understanding of their vibrational behaviour. Although there are many sources that describe the impact of braces on the natural frequencies of guitar tops, there exists a paucity of research that delves into how these structures achieve their effects.
The purpose of this paper is to employ FEM to examine the effect of braces on the soundboard and to contrast the results with those obtained from an actual soundboard fabricated by the author. Through simulation, we aim to elucidate the influence of various factors such as position, height, and profile on the soundboard's performance. However, it is important to note that there may be discrepancies between the simulation results and the actual performance of the soundboard owing to measurement errors and constraints associated with manual production. As a result, the data generated by this study should not be regarded as reference data.
Radiation measurements have been employed in research for close to a century and over the last years a growing interest for application in workshops has developed. However, some problems of standardization mainly pertaining to room acoustics arise, which make measurement results comparable only to those conducted under the same circumstances. Our aim is to modify measurement procedure and rig design in such a way, that comparable results can be attained even in acoustically non-ideal spaces. A specialized rig for violin radiation measurements was constructed leaning on partial automation to allow for the application of thick curtains as a means of decoupling measurements from the surrounding room. Trial runs in an acoustically challenging space - our living room - as well as in a small studio environment were conducted.
Improvements of measurement results were obtained for frequencies above 800 Hz, measurements were influenced significantly by the surrounding room below that threshold. As a result, calculated features were heavily skewed by the environment, rendering obtained data useless for statistical purposes. Therefore additional measurements of six instruments were performed in a small studio environment and features as defined in the literature calculated. Correlations with listening test results concerning the evenness of sound as well as structural instrument parameters were obtained. Listening test results were inconclusive, which is proposed to be attributed to the narrow range of instrument quality available for trials. Some interesting correlations of measurement features with structural parameters could be obtained and further vetted through the comparison with a second set of data. Three correlations were found which were significant or approaching significance in both groups, giving a more complete connection from instrument making to sound perception. Furthermore we have found some interesting correlations of structural parameters, giving insights into maker decisions and corroborating some workshop wisdoms.