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Manufacturing sustainability and life cycle management in the production of acoustic guitars
Abstract
The manufacture of stringed instruments has strong elements of traditional practice, particularly in the choice of materials from which the instruments are made. While man-made materials have been used in successful instruments, they are overwhelmingly made of wood. The preferred species include Sitka spruce, mahogany, rosewood and maple. Furthermore, the grade of materials used for instruments is extremely high, only one step below that used for the load-carrying structures of aircraft. The ideal piece of wood is straight-grained and without imperfections such as knots, checks or discolouration. The growth rings should be close together, so slow-growing trees are preferred. The result is that trees yielding instrument-quality wood have been heavily logged and are becoming very scarce. This is reflected in the rising prices of instrument grade wood. At this writing, a master-grade top blank for a single acoustic guitar can cost up to 1 billion per year, so the demand for materials is not going to ease soon. Clearly, the industry must change its practices if it is to sustain production. Several fundamental changes are required. The strong prejudice against laminated materials must be overcome. High grade plywood exhibits structural properties and uniformity that would make it ideal for instrument manufacture, but its use is limited to student grade instruments. The Convention on International Trade and Endangered Species (CITES) outlines the terms under which traditional species can be legally and sustainably harvested, but it limits production volumes and the temptation to skirt the regulations is strong. Thus, another required change is to switch to fast-growing species. Finally, manufacturing processes must be modified and life cycle management procedures should be implemented to allow for the effective and efficient use of smaller, younger trees.
... Pakarinen and Asikainen [2] confirmed that "aesthetic attributes" are important for consumers when evaluating wood products. In addition, because wood is often used in musical instruments, its "traditionality, " "decay resistance, " and "scarcity" attributes have been emphasized [3]. Thus, this study proposes hypotheses regarding the relationship among the aesthetics, traditionality, decay resistance, scarcity, and price persistence of musical instruments. ...
... Several species of wood are used in the production of musical instruments [3,5]. Advances in musical instruments have resulted from advances in the use of wood [26]. ...
... Wood deteriorates over time due to a variety of environmental factors (e.g., mold, insects, rainwater). Therefore, using high-quality wood that is resistant to decay increases the functionality of wood products [3]. Guitars are wood products with both structural (i.e., the shape of a product and the way it is manufactured) and acoustic specifications [28]. ...
Wood attributes are important, because they directly affect the price persistence of wood products. Consumers consider the “aesthetic,” “traditionality,” “decay resistance,” and “scarcity” attributes important when evaluating wood. This study analyzed the impact of these four attributes on the price persistence of acoustic guitars. We obtained data from a Japanese internet auction platform and winning-bid data for two representative brands, Martin and Yamaha. We performed a quantitative analysis using the winning bid price as the dependent variable and the adoption of various wood attributes in each part of the guitar corresponding to the four attributes as explanatory variables. We found that rosewood, mahogany, palisander, and ebony have a significant impact on price persistence, and that all of them fit the four attributes of traditionality, decay resistance, scarcity, and aesthetics. We also found that traditionality was the key attribute among the four. Using wood in luxury brands without traditionality was not effective, even if other attributes were present. For mass-market brands, scarcity and decay resistance had positive effects on price persistence. The finding that scarcity and decay resistance were important only for mass-market brands can help companies understand market demand, determine product attributes, and achieve product–market fit.
... For these reasons, most manufacturers only use material that has mechanical properties which fit within their set criteria. Such an approach leads to much waste [3]. ...
... where a is the desired frequency and b 1 -b 3 are unknown values which need to be found. Since we have assumed 2 × 2 trial functions so that the mass and stiffness matrices are both 4 × 4, the characteristic polynomial must be fourth order, as shown in equation (2). ...
The manufacture of acoustically consistent wooden musical instruments remains economically demanding and can lead to a great deal of material waste. To address this, the problem of design-for-frequency of braced plates is con-sidered in this paper. The theory of inverse eigenvalue problems seeks to address the problem by creating representative system matrices directly from the desired natural frequencies of the system. The goal of this paper is to demonstrate how the generalized Cayley-Hamilton theo-rem can be used to find the system matrices. In particular, a simple rectangular brace-plate system is analyzed. The radial stiffness of the plate is varied in order to model variations typically found in wood which is quartersawn. The corresponding thickness of the brace required to keep the fundamental natural frequency of the brace-plate sys-tem at a desired value is then calculated with the pro-posed method. It is shown that the method works well for such a system and demonstrates the potential of using this technique for more complex systems, including sound-boards of wooden musical instruments.
... Since the demand for solid wood leads to a resource problem, it becomes necessary to turn to alternative sources in instrument production. Hybrid or synthetic materials are materials suitable for instrument production and cost (French et al., 2009). However, these materials also need to be of high quality and compatible with each other. ...
The demand caused by the decreasing number of tree species used in guitar production every day is being tried to be met with artificial materials in the 21st century. Guitars are produced mainly in countries where cheap labor and materials are sold at affordable prices, attracting much attention in Turkey and the rest of the world. This type of guitar, sold in some chain markets in Turkey several times a year, attracts the attention of those who mainly want to get a guitar education at the beginner level. This research aims to determine the technical, musical, and structural competence level of imported guitars used at the beginner level in Turkey. In the research conducted in the case study pattern, we studied five people who are experts in their field. "Guitar Technical and Musical Evaluation Form" and "Guitar Structural Evaluation Form" were used as data collection tools by expert opinions. The obtained data were analyzed with the appropriate computer program. The content analysis of the answers given to the open-ended questions was carried out. As a result of the research, it has been found that the guitars in question are regular in appearance, but they are technically and musically found to be incompetent. However, it has been found that the guitars are structurally proportional, but the wood quality needs to be improved. All experts have stated that these instruments have an intonation problem and are unsuitable for guitar education. As a result of the research, it is proposed to officially determine the standards of guitars and allow their import within the framework of these standards.
... see (Handy) that green manufacturing refers to a multidisciplinary approach that aims to reduce energy and material consumption, and the intensity of manufacturing operations. Such as actualization of operations and scheduling, advanced/improved manufacturing techniques, reduced waste volume, and improved energy efficiency (Handy, 2008). ...
The research aims to find out the impact of the practices of green supply chain systems and technology-reverse logistics, green information systems and green manufacturing-on the environmental performance of the economic units operating in the oil sector. Realizing the impact of the practices of green supply chain systems and technology-reverse logistics, green information systems and green manufacturing-on the operational performance of economic units in the oil sector. Examining the effect of the practices of green supply chain systems and technology-reverse logistics, green information systems and green manufacturing-on the operational performance of economic units in the oil sector. Testing the proposed model for the effect of green supply chain systems and technology practices on the performance of the economic unit in the oil sector.(SPSS 23), where the researchers concluded, that green supply chain systems and technology are contemporary and important topics for economic units, because they seek to reduce negative environmental impacts and production costs, as well as an important way to make economic units sustainable and green. The researchers recommended it, the need for economic units to realize the importance of green supply chain systems and technology and their operations, because they have the full perception and vision and direct influence in aspects of economic units.
... The raw materials used in guitar production can be divided into direct materials and indirect materials. The main element of direct raw material is the wood [5]. The choice of wood will affect the quality of the guitar. ...
Wira Musica is one of the Small and Medium Enterprises (SMEs) in guitar manufacturing located in Sukoharjo Indonesia which produces various types of guitar, such as electric guitar, bass guitar, acoustic guitar, etc. To meet the demands of various products, Wira Musica faces difficulties in production planning to generate maximum profit. This paper aims to develop a linear programming model to determine the optimal production of the guitars. OptQuest of Oracle Crystal Ball software is used to solve the linear programming model. From the results, the guitar manufacturer can achieve the maximum profit by producing only four of its five products. The fifth product did not give impact to maximize profit. The linear programming model gave a higher benefit than the current production plan of 11.09%. By using a linear programming method, Wira Musica can develop an effective, efficient, and optimal production plan by considering aspects of limited resources such as raw materials, labor, and working hours.
Classical guitar necks were submitted to 40, 65 and 80% relative humidity (RH) during time periods ranging from 24 h to several months, and moisture-induced deformations were observed. Different types of classical guitar necks were investigated in terms of structure and reinforcement. The influences of the wood species and the neck reinforcements on the moisture content (MC)-induced deformation were in focus. First, before humidity exposure in the climatic chamber, the relative positions of three points marked on each sample were measured with a control ruler and noted. After exposure, the displacement of the reference points on the samples were verified periodically. The differences between the measurements in different stages and reference positions were calculated, resulting in relative displacement data of the measured points. During the experiments, the MC of the sample was monitored by weighing. The variation of RH leads to dimensional instability and moisture-induced stresses of the guitar necks, which affect the acoustic quality of a guitar. Steel enforcement of the guitar neck improves this situation.
The potential of materials derived from natural or sustainable forest resources for musical instruments has been discussed. The quality of wood species from natural forest resources, having acoustical properties unsuitable for the production of musical instruments can be improved by biological, chemical or physical treatments. The biological treatment refers to the process of decreasing wood density which can be achieved with fungi causing a selective delignification of wood, such as Norway spruce or sycamore that have a ordinary anatomical structure. The selected fungi, at the incipient stage of the attack do not have the enzymatic potential to degrade the middle lamellae of the cellular structure of timber. This procedure can improve the acoustical properties of wood without significantly destroying its mechanical capacities. The chemical treatment refers to the improvement of dimensional stability of spruce for violins produced by the industry. The physical treatment of wood refers to thermal treatment under atmospheric pressure and to the treatment of wood under hydrostatic pressure at normal temperature. New materials from sustainable forest resources have been studied. To overcome the shortage of tropical wood species and of resonance wood for musical instruments, plywood having a specific structure or produced from fast-growing trees could be an obvious alternative. Synthetic materials such as ebonite and plastics can be used to produce student model instruments. Recycling sustainable wood fibres or polymers and developing specific injection molding technology can contribute to mass production of student model musical instruments of good acoustic quality.
Land use and land cover change is an important driver of global change (Turner et al., 1993). It is recognized that land use change has important consequences for global and regional climates, the global biogeochemical cycles such as carbon, nitrogen, and water, biodiversity, etc. Nevertheless, there have been relatively few comprehensive studies of global, long-term historical changes in land cover due to land use. In this paper, we review the development of global scale data sets of land use and land cover change. Furthermore, we assess the differences between two recently developed global data sets of historical land cover change due to land use. Based on historical statistical inventories (e.g. census data, tax records, land surveys, historical geography estimates, etc) and applying different spatial analysis techniques, changes in agricultural land cover (croplands, pastures) were reconstructed for the last 300 years. The two data sets indicate that cropland areas expanded from 3–4 million km2 in 1700 to 15–18 million km2 in 1990 (mostly at the expense of forests), while grazing land area expanded from 5 million km2 in 1700 to 31 million km2 in 1990 (mostly at the expense of natural grasslands). The data sets disagree most over Latin America and Oceania, and agree best over North America. Major differences in the two data sets can be explained by the use of a fractional versus Boolean approach, different modelling assumptions, and inventory data sets.
Since resonant plates in stringed musical instruments are made from coniferous woods, particularly from spruce, with maximum quality requirements, investigations were carried out in order to test the use of other materials for this purpose. These were aluminium plates with two types of visco-elastic layer, and laminates of glass fiber reinforced epoxy and unsaturated polyester resin, with reinforcements of several types, but preferably unidirectional fibers. The conclusions resulting from the measured data of sound velocity and damping in the audible frequency range only encourage further research upon laminates of glass fiber reinforced plastics.
In the paper under discussion, the authors conducted a survey on several qualities of resonant wood, particularly conifer, in view of their suitability for violin top plates and piano soundboards. They reported their experiments with several agents, especially with formaldehyde to improve certain physical properties. It will be shown that the discussion about acoustical magnitudes of resonant wood, although detailed, should be complete and that some results do not correspond to previous knowledge.
A violin has been constructed with a graphite?epoxy sandwich plate replacing the usual spruce top plate. This substitute plate is similar in design to that previously described for a guitar application [D. W. Haines, N. Chang, and D. A. Thompson, J. Acoust. Soc. Am. 55, S49(A) (1974)]. Modern methods of violin design and construction produced an instrument with qualities which compare favorably with those of superior violins constructed entirely of wood. Frequency response curves and mode shapes are presented of the detached graphite?epoxy plate. Shown also are frequency response curves of the complete instrument. Comparisons with similar tests of high?quality wood plates and instruments are also given. The new violin will be available for examination. [Assistance from Mr. Stan Cross of Hercules Inc., Mr. John C. Schelleng, and Dr. Karl Stetson. Supported by National Science Foundation Grant GK?35913.]
Acoustical effects of violin varnish—those of mass, stiffness, and internal friction—are examined qualitatively and quantitatively. Dynamic measurements of Young's modulus, real and imaginary, are made for films of typical oil varnishes on a substrate of cross‐grain spruce through aging periods of 1 yr or more and expressed in the practically useful terms of modulus over density. After 1 1 2 yr , the hard varnish had a real modulus per unit density of 2.5 × 1010 cm2/sec2 and Q about 23; after 1 yr, the values for the soft varnish were 1.6 × 1010 and 8. A high‐grade floor varnish had intermediate values. The imaginary component of the soft one was substantially independent of frequency from 400 to 5600 cps. Exact calculations of added loss and tuning shift, made for a “pseudofiddle” comprising rectangular top and back of orthotropic materials simulating spruce and maple, are believed roughly representative of the violin. Added loss is more apt to be damaging than is detuning of plates. The loss comprises two components: (1) a reduction in sound caused by the reactive parameters of varnish, i.e. mass and stiffness, and effective irrespective of resonance; and (2) one caused by internal friction and greatest at a resonance. With an intermediate varnish, a coat of 0.0127 gm/cm2 (thickness about 0.005 in.) causes “flat” loss of about 1 dB and resonance loss about 3 dB; this is excessive. Varnish loss in the top plate is about three times that in the back; unless the spruce is overly resonant, its varnish should be thin. Top is more subject to detuning than back. Loss due to varnish is best controlled by weighing, with final adjustment of wood thickness after varnishing.
The acoustic characteristics of carbon fiber-reinforced synthetic wood for musical instrument soundboards were discussed. It was observed that the composite with three symmetrical layers, reinforced with intersecting fibers showed reduced fiber slackness and better penetrance of polyurethane resin into the carbon fiber strands. It was also observed that the composite was determined by the Young's modulus of the polyurethane foam. It was found that the synthetic wood would make it possible to supply materials with optional and stable properties.
In order to investigate the possibility of Oriental lacquer (urushi) as a coating for the wooden-soundboard of musical instruments, the effects of urushi coatings on the vibrational properties of wood were compared to those of conventional coatings. By coating, the dynamic Young’s modulus of wood decreased slightly in its fiber direction whereas that in the radial direction increased. The most remarkable changes due to coating were recognized in the internal friction of wood (Q-1), especially that in the radial direction. The effect of the urushi coating on the Q-1 of wood was relatively small and very close to those of polyurethane coating used for the soundboard of harp. The viscoelastic and mechanical properties of urushi lacquer films were also similar to those of the polyurethane lacquer film. These results suggested the possibility of urushi as a coating for the harp soundboard. The effects of coatings on the vibrational properties of wood were explained by using a model considering three layers, the uncoated wood, coating layer, and a layer consisting of lacquer and wood cell wall.
A new type of wood-based material for guitar back plates as a substitute for Brazilian rosewood was produced based on Japanese cedar logs with a small diameter, of which the utilization is limited despite its availability. The sapwood portion of logs with a diameter of 20 cm was processed to veneers of 2 mm thickness using a rotary lathing machine. The veneers were impregnated with a low-molecular-weight phenolic resin, laminated in parallel, and compressed perpendicular to their plane. When the veneers were treated with a 3% or 5% aqueous solution and compressed to a density of 0.8 without adhesives, the specific dynamic Young's modulus (E/gamma, ratio of stiffness to specific gravity) and tan delta (damping) of the materials became almost the same as those of Brazilian rosewood in the lower-frequency range, not only in the longitudinal direction but also across the longitudinal direction. However, the frequency dependencies of the specific Young's modulus and tan delta of the materials differed from those of Brazilian rosewood, which may be partially related to the higher values of E/G of laminated compressed wood as a result of the increased density induced by deformation of the cell walls. (C) 1997 Acoustical Society of America.
After a review of the structure of wood concerning its acoustic properties and a discussion of the merits and demerits of wood as a material for making soundboards of stringed instruments, the effects of three chemical treatments (a low molecular weight phenolic resin treatment, a resorcin/formaldehyde treatment, and a saligenin/formaldehyde treatment) on the acoustic properties of Sitka spruce wood are reported and compared with those of formaldehyde treatment. All three chemical treatments increased the specific dynamic Young's modulus and greatly decreased dumping (tan δ) without greatly increasing specific gravity. The range was almost equivalent to that with formaldehyde treatment whose superb effects have already been confirmed in the violin. With saligenin/formaldehyde treatment, the frequency dependence of tan δ could be controlled over a wide range by changing the saligenin concentration. In all treatments, hygroscopicity was reduced and dimensional stability was improved significantly.
Response curves, important both for steady sound and transients, give a far‐reaching insight into the objective characteristics of violins: good ones exhibit large amplitudes at low frequencies and small ones at high frequencies, a broad minimum near about 1500 cps, and larger amplitudes between about 2000 and 3000 cps. The musical subjective significance of these physical properties is mentioned briefly. In general, the sound pressure radiated from a violin follows the inverse‐distance law, being independent of frequency. The influence of wood thickness is very important, that of the varnish is comparably small. Pine has a greater damping at high frequencies than at low frequencies. This seems to be a good acoustical reason for making important parts of stringed instruments of pine. Sapwood is better than heartwood. Similarly, some kinds of varnish produce more damping at high frequencies than at low frequencies. If a resonance curve is to be imitated in detail, it is necessary to change carefully the wood thickness of certain parts of the violin body. The applicability of present‐day scientific knowledge to the construction of violins is here outlined.
The changes in frequency response function (FRF) of a guitar top plate due to different machining processes used to finish the guitar tops were analyzed. The way of machining the tops had a measurable but hardly explainable effect on their FRF because of not well-separated frequency peaks. The additional measurements of FRF of differently machined square-shaped plates showed more clearly the influence of the machining process on the acoustic properties of a wooden board. Therefore, a general conclusion is that the machining process influences the acoustic properties of a wooden board. The reason for this influence lies in the different surface shapes of differently machined boards.
Formulae for determination of relevant physical and acoustical characteristics of material are given considering waves spreading in a thin elastic bar. An apparatus, AKUSTOMAT, is described, that can carry out both the measurements and the 3D data presentation. Experimental results are obtained on the high quality resonant and current spruce wood, and on high and low quality maple woods. The sorting of materials can be based on the evaluation of the physical and acoustical characteristics. Using these ideas, the possibilities of wood identification for making musical instruments are introduced.
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