TY - CHAP A1 - Clauder, Lothar A1 - Munk, Christoph A1 - Pfriem, Alexander T1 - The influence of thermal modification on the initial material-brightness (L*), documented by in-situ measurements T2 - European Conference on Wood Modification 2022 N2 - In this study, the influence of the thermal modification on the characteristic brightness of the raw material Alder (Alnus rubra) and Maple (Acer pseudoplatanus) was investigated by spectral photometric in-situ analysis. KW - thermally modified wood KW - brightness (L*) (CIELab*) KW - process control Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:eb1-opus-2801 ER - TY - CHAP A1 - Munk, Christoph A1 - Clauder, Lothar A1 - Pfriem, Alexander T1 - Acoustical comparison of two different guitars, made of untreated tropical wood and thermally modified wood, using a frequency response analysis T2 - Northern European Network for Wood Science & Engineering (WSE) N2 - To this day, many guitar makers around the world use primarily tropical woods such as rosewood (Dalbergia spp.) for their production. Due to the current CITES regulation of January 2017 regarding the trade of tropical woods, it becomes inevitable to generate alternative materials with similar material properties to be generated and established. Part of this study is an acoustic comparison of two guitars. One made of untreated tropical wood [Dalbergia nigra Benth.)] and one made of European thermally modified wood (TMT) species. [Pyrus (L.) and Alnus (Mill.)]. The method used allows a significant statement about the acoustic radiation performance of stringed and plucked instruments. The experimental setup consists of an impulse hammer for excitation of a force in the center of the bridge and a microphone for recording the signal radiated by the guitar body at a distance of one meter from the sound hole. A front-end was used to record the data, and further processing was done using analysis software to determine frequency response functions (FRFs) of the two instruments. The FRFs determined can be subdivided into several ranges which contain the different acoustic information about bass range, loudness, clarity, brightness and sharpness of the instruments. Examination of the frequency ranges reveals an acoustic similarity between the two guitars. Slight differences can be seen in the bass and loudness areas, where the guitar from TMT has a higher average level. Clearer differences are offered by the areas of clarity, where the guitar made of tropical wood shows a higher average level. In summary, the method gives an efficient acoustic impression as a function of the natural frequencies of the two guitars. The measured data show similarities and thus comparable acoustic properties of the instruments. However, additional effects such as psychoacoustic sensations or musical taste for the complete acoustic impression of an instrument are also of importance. Therefore, further empirical and fundamental research is needed to obtain a more detailed acoustic impression of the instruments. KW - TMT KW - FRF KW - guitar Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:eb1-opus-2850 ER - TY - CHAP A1 - Munk, Christoph A1 - Clauder, Lothar A1 - Pfriem, Alexander T1 - Sound absorption coefficient of thermally modified and unmodified wood species measured in an impedance tube T2 - Northern European Network for Wood Science and Engineering (WSE) - 15th Annual Meeting 2019 N2 - Different parts of the guitar body are made of certain wood species, selected by their specific properties. The sound board, which is mainly made of spruce or cedar, transfers the vibration of the strings to the resonance body by means of the bridge. The sides and the back of the guitar rather reflect the sound of the acoustic vibrations and are predominantly made of tropical hardwoods like palisander, mahogany or ebony species. These species have limited availability and are listed on the CITES Annex I and II. To substitute tropical wood species, thermally modified European wood species with improved acoustic properties and dimensional stability may be used. Although the acoustic reflection of the sides and the back parts of a guitar body is an important property, there is not much knowledge about this reflection behaviour of wood. A few studies like the work of Hong (1989), Kang (2010) or Smardzewski et al. (2013) investigated the sound absorption properties of unmodified wood. Subsequently this study considers the sound absorption coefficients of unmodified and thermally modified European wood species in comparison to an unmodified tropical wood species. KW - TMT KW - sound absorption coefficient KW - impedance tube Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:eb1-opus-2890 ER -