Akustika最新文献

{"title":"THE INFLUENCE OF ROOM ACOUSTIC PARAMETERS ON THE PERCEPTION OF ROOM CHARACTERISTICS","authors":"A. Jasińska, M. Kin","doi":"10.36336/akustika20203728","DOIUrl":"https://doi.org/10.36336/akustika20203728","url":null,"abstract":"The article presents the possibility of identification of rooms on the basis of binaural perception. Results of subjective evaluation were compared with the values of sound strength, G. A previously unknown sound term was introduced: the strength of spatial impression as the inverse of standard deviation of the results obtained. It turned out that the results presenting the sound strength parameter can be correlated with the subjective evaluation of the spatial impression, which is the size of the room. It can be helpful in the process of room identification, probably due to the reverberation impression in the room. Authors plan to continue the study with more rooms and different types of sound sources.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41589103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"INFLUENCE OF THE THICKNESS OF THE BACK WALL OF A WOODEN ORGAN PIPE AND THE AIR PRESSURE IN THE WIND CHEST ON ITS SOUND PROPERTIES","authors":"Andrej Štafura, K. Tuhárska, Š. Nagy, A. Danihelová","doi":"10.36336/akustika20203786","DOIUrl":"https://doi.org/10.36336/akustika20203786","url":null,"abstract":"The paper presents the results of the study of the influence of the back wall thickness of an organ pipe made of resonant spruce wood and the air pressure in the wind chest on its frequency spectrum. A wooden organ pipe with a replaceable back wall was used in the experiment. The wooden plate used for the back wall had an initial thickness of 7 mm. The plate was gradually thinned in 1 mm decrements to a thickness of 1 mm. For each plate thickness, the frequency spectrum was scanned at four different air pressures, namely 588 Pa, 716 Pa, 814 Pa and 941 Pa. The results of the experiment showed that at a given back wall thickness, the fundamental tone frequency increases with increasing air pressure. The decrease in the back wall thickness was manifested by a decrease in the fundamental frequency. At an air pressure of 716 Pa, the intensity of the fundamental as well as the second harmonic component of the pipe acoustic spectrum increased slightly at all wall thicknesses. With increasing air pressure, the intensity of higher harmonic frequencies also increased. The decrease in the back wall thickness of the wooden organ pipe had only a minimal effect on the intensity of the individual harmonic components of the frequency spectrum. Changing the thickness of the back wall of a wooden organ pipe will not significantly affect its final sound.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42018873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ANALYSIS OF SOUND SPEED IN LONGITUDINAL DIRECTION AT REFERENCE MOISTURE CONTENT (w = 12 %) IN SAWMILL ASSORTMENTS (FAGUS SYLVATICA, L.)","authors":"A. Rohanová","doi":"10.36336/akustika20203745","DOIUrl":"https://doi.org/10.36336/akustika20203745","url":null,"abstract":"This paper explores the analysis of sound speeds in the longitudinal direction and their reduction to the reference moisture content w = 12 %. The sound speed cw was determined with Sylvatest Duo device. Moisture content of beech sawmill assortments (round timber: N = 16, logs: N = 2 × 16, structural boards: N = 54) in the range of 12 – 72 % was measured. For the analysis purposes, the sound speed was converted to reference conditions (c12, uref = 12%). A second-degree polynomial (parabola) with a regression equation of the form: c// = 5649 - 27,371 × w + 0.0735 × w2 was used to convert cw to c12, and correction of measured and calculated values was used as well. The sound speeds c12 in sawmill assortments (c12,round, c12,log, c12,board) were evaluated by linear dependences. Dependence was not confirmed for c12,round and c12,board1 (r = 0.168), in contrast for c12,round and c12,log2 the dependence is statistically very significant (r = 0.634). The results of testing showed that the most suitable procedure for predicting quality of structural timber is the first step round timber – log2, the second step: log2 - board2. More exact results of the construction boards were obtained from log2 than from log1. The sound speed is used in the calculation of dynamic modulus of elasticity (Edyn). EN 408 mentions the possibility of using dynamic modulus of elasticity as an alternative method in predicting the quality of structural timber.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48880643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"THE ASSESSMENT OF NOISE GENERATED BY HEAT PUMPS INSTALLED OUTDOORS","authors":"M. Flimel","doi":"10.36336/akustika2020372","DOIUrl":"https://doi.org/10.36336/akustika2020372","url":null,"abstract":"Energy-efficient buildings utilise the potential of renewable sources, among which heat pumps hold an important position. As this technology has a secondary effect on the environment through its noise immission, locations of outdoor units in the exterior should be subjected to the assessment. The present article deals with the options of placing heat pumps in the exterior and the placement assessment methods. The noise burden identification through the assessment of the time exposure is presented in the example of an in situ measurement.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44614208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A BRIEF OVERVIEW OF SOUND REPRODUCTION SYSTEMS FOR LISTENING TESTS USED IN THE SUBJECTIVE EVALUATION OF SOUND INSULATION","authors":"Dominik Kisić, M. Horvat, K. Jambrošić, Vedran Planinec","doi":"10.36336/akustika20203732","DOIUrl":"https://doi.org/10.36336/akustika20203732","url":null,"abstract":"This article does not present an in-depth overview but is meant to serve as an introduction to the newcomers to this field of acoustics. A brief explanation is given for different sound reproduction formats (Ambisonics and binaural), together with some of the standards, and listening test tools used in the design of listening tests. Primarily the listening tests in the field of subjective evaluation of sound insulation and acoustic comfort have been discussed.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48420346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SOUND ABSORPTION ON BOARD CONSTRUCTION MATERIALs USED IN WOOD BUILDINGS","authors":"M. Culik, A. Danihelová, Vojtěch Ondrejka, P. Alac","doi":"10.36336/akustika20203751","DOIUrl":"https://doi.org/10.36336/akustika20203751","url":null,"abstract":"When the sound wave touches the material (wall), some fraction reflex the wall, other fraction is absorbed and the rest fraction of the sound wave will go through the wall. So, in every enclosed space we can say about sound absorption, transformation of sound energy into some other energy. Sound absorption coefficient α (-) can be mentioned as criteria for the standard of sound absorption by the material. The article deals with the evaluation of sound absorption in the chosen materials which are utilised in wooden buildings, construction parts of partition walls and ceilings, floors and walls cover. There were used the following materials which are applied in the construction of wood buildings: particleboard (DTD), oriented strand board (OSB), beech plywood (PDP_BK), poplar plywood (PDP_TO), tetra pak recycled board (TETRA K), gypsum fibreboard (Fermacell), cement chipboard (CTD), plasterboard (Rigips) and medium-density fibreboard (MDF). The measurement was performed by the transfer function method in accordance with the standard ISO 10534-2. Under the frequency in the range 200 Hz – 2.0 kHz, the highest values of sound absorption coefficient were measured in CTD, PDP_TO, DTD and OSB within the interval from 0.05 to 0.53. Fermacell and Rigips have the highest values of sound absorption coefficient (0.3 – 0.4) within the frequency from 2.5 kHz to 4 kHz. At the same time, Fermacell, Rigips, but also MDF and TETRA K boards reached the lowest sound absorption (0 – 0.21) within the frequency interval 50 Hz – 2.0 kHz. Sound absorption assessed on the base of NRC coefficient was measured as very low (under 0.2) for all assessed materials, except of CTD. The tested board materials according to the standard ISO 11654 can be included among sound reflective material and little sound absorptive material. The highest level of noise reduction coefficient αNRC was measured at cement chipboard CTD (αNRC = 0.3) which can be included among absorptive materials. The results should be transformed into predictions in room and building acoustics, particularly in the design and projection of partition wall constructions in ultra-low energy buildings but also in the entire interior equipment.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43633356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"THE IMPACT OF ACOUSTIC OF SELECTED SPACES ON PERCUSSION INSTRUMENTS","authors":"Vojtěch Ondrejka, T. Gergeľ, A. Danihelová, M. Culik, D. Bednárová, Marián Schwarz, M. Němec","doi":"10.36336/akustika20203772","DOIUrl":"https://doi.org/10.36336/akustika20203772","url":null,"abstract":"The results of the investigation of the room acoustic properties influence on the perception of the sound of percussion musical instruments are presented in the paper. At first, the acoustic properties of two rooms were determined without musical instrument. Subsequently, the acoustic properties of the rooms were determined during the presentation of cajon music. On the base of reverberation time (EDT, T30), Clarity C80, Definition D50 and bass index BI) we can conclude that the room of the Hron cinema is more suitable for musical presentation, but it cannot be considered as ideal one. The Royal Hall of Zvolen Castle has a smaller influence on the sound of a percussion instrument. The influence of room acoustic properties on the resulting sound of the instrument was evaluated only on the base of results obtained with using the objective methods by the physical quantities measurement. Finally, the design of these rooms modification is presented to achieve a better sound quality of percussion instruments.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44128841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"METHODOLOGY OF OBJECTIVE EVALUATION OF THE QUALITY BEARINGS BY VIBRO-ACOUSTICS AND ITS COMPARISON WITH A SUBJECTIVE METHOD","authors":"S. Ziaran, O. Chlebo, L. Soos","doi":"10.36336/akustika20203758","DOIUrl":"https://doi.org/10.36336/akustika20203758","url":null,"abstract":"The quality of bearing production has an impact not only on their reliability and lifetime, but also on the dynamic load of the working and living environment by excessive vibration and thus also noise. The intensity of the noise emitted by a bearing which is perceived by man characterizes the quality of its production. Reducing the dynamic load of mechanical systems and their components is reflected in the working environment by reducing noise emissions and immissions. The article proposes an objective method of bearing quality assessment based on measuring vibro-acoustic parameters of dynamic load of a new bearing using FFT analysis and the magnitude of the amplitude of bearing vibration acceleration and compares it with a subjective method that also uses the human auditory organ to assess bearing quality. The results of vibro-acoustic measurements were analysed in terms of vibration intensity and the noise of the produced bearings. The proposed objective methodology was compared with the subjective evaluation of the quality of bearings and the results of this methodology matched. The proposed methodology is applicable to all types of bearings, and it is possible to automate this methodology in the production process.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43126944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SPEAKER DISCRIMINATION IN MULTISOURCE ENVIRONMENTS AURALIZED IN REAL ROOMS","authors":"K. Jambrošić, M. Horvat, Dominik Kisić, T. Oberman","doi":"10.36336/akustika20203719","DOIUrl":"https://doi.org/10.36336/akustika20203719","url":null,"abstract":"With the recent development of audio in modern VR/AR systems and the increasing capability of synthesizing natural sound fields over headphones with head tracking, the question of the ability of our hearing system to discriminate multiple concurrent sound sources has become important again. We must understand how psychoacoustical and psychophysical limitations of the hearing system cope with novel technologies of virtual acoustics that can simulate an almost unlimited number of sound sources. Previous research has shown that the capacity of human hearing to discriminate a reference sound source is limited when there is background noise, a reverberant surrounding, or when other, disturbing sound sources simultaneously mask the reference source. A set of listening tests based on the cocktail-party effect was designed to determine the intelligibility of speech emitted by a reference sound source, with one to six disturbing sound sources simultaneously emitting speech from different directions around the listener. The tests were repeated in three test rooms with different acoustical properties, and two test signals were used: logatomes and regular spoken sentences with specific keywords. The results have revealed the changes in speech intelligibility scores in relation to the number of disturbing sources, their positions, and acoustical properties of test rooms.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44300689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New definitions of base units valid from 2019","authors":"","doi":"10.36336/2019355","DOIUrl":"https://doi.org/10.36336/2019355","url":null,"abstract":"Metrology and uncertainty are one of the traditional topics of the Acoustics seminars every year. This paper is therefore more oriented towards theoretical metrology, although the context of measurement uncertainty will be maintained. This year a fundamental amendment to metrology came into force-new definitions of basic SI units. While this change should not have a major impact on common practical measurements, it still deserves our attention, eventually reflection on the potential impacts on the field.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42040208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}