odborný časopis o akustice a vibracích
Journal Akustika is peer reviewed journal indexed in Scopus database and Web of Science.
EUROPEAN MOUNTAIN ASH AS A POSSIBLE SUBSTITUTE FOR HONDURAN ROSEWOOD IN THE PRODUCTION OF XYLOPHONES
The sound quality of a xylophone depends on the material it is made of. The xylophone produces sound through the vibration of the wooden bars. The bars are usually made of rosewood or padauk due to their properties, resonance, and durability. However, the Honduran rosewood is a protected wood species, so it is necessary to look for other suitable wood species. Based on the investigation of the physical and acoustical characteristics of the various wood species, it appears that the European mountain ash (also known as rowan) may be a suitable substitute for the Honduran rosewood. Unlike the Honduran rosewood, the European ash is not listed in the CITES appendices or on the IUCN Red List of Threatened Species. The effect of modification of the European mountain ash on the physical and acoustical characteristics (PACHs) and sound quality was investigated. The wood samples were modified in two ways: mechanical densification and a combination of mechanical densification and thermal modification. The PACHs (density of wood ρ w, modulus of elasticity along the wood grain EL , acoustical constant A, loss coefficient η, specific modulus of elasticity E sp, acoustic conversion efficiency ACE, speed of sound along the wood grain cL ) were measured before and after modification. These PACHs were compared with the characteristics of the Honduran rosewood. The sound quality of the xylophone bars produced before and after modification was also determined. Following the experiment results it can be stated that the wood of the European mountain ash, after combination mechanical densification and thermal modification, can be used as an alternative to the Honduran rosewood for the xylophones of lower quality.
Copyright (c) 2025 Martin Čulík, Anna Danihelová (Author) https://creativecommons.org/licenses/by-nc-nd/4.0
ASSESSMENT AND COMPARISON OF SOUND INSULATION OF SELECTED PARTITION CONSTRUCTIONS IN TWO WOODEN BUILDINGS
Acoustic comfort in an inhabited building is an important aspect from the point of view of a person’s quality of life, especially in the hotels and the buildings for the temporary accom- modation facilities. When evaluating the sound insulation of the partition walls and ceilings, measurements carried out in buildings are decisive, which can confirm the suitability of the material composition used and its correct application in the wooden building. The work deals the evaluation of the airborne and impact sound insulation of the partition constructions of a different thickness and material composition between the rooms in two different residential houses. The results of the airborne sound insulation measurements showed that, even after considering the required spectrum adaptation terms, the requirements of the standard STN 73 0532-2:2024 were not met in the first building, but they were met in the second building. The results of the impact sound insulation measurements showed that the requirements of the new standard STN 73 0532-2:2024 were not met in the first building after considering the required spectrum adaptation term Ci50-2500 but were met in the second building after considering all required spectrum adaptation terms.
standardized impact sound pressure level
Copyright (c) 2025 Martin Čulík, Michal Hrčka, Anna Danihelová (Author) https://creativecommons.org/licenses/by-nc-nd/4.0
Insights and Limitations of Acoustic Stress Tomography in Forestry Applications
Effective wood evaluation necessitates a thorough consideration of technical parameters, including both quantitative and qualitative features. The study aimed to practically verify the accuracy and applicability of the ARBOTOM acoustic stress tomograph under various forestry operations and research conditions. The tomograph was tested in a forest stand and a poplar plantation. A total of 165 standing tree trunks were evaluated using the acoustic tomograph: 108 oaks, 53 lindens, 4 pines, 1 fir in the forest, and 2 poplar trunks at the plantation. The median value for damage identified in the red color spectrum was 41.4% for oak and 58.3% for linden. In the violet color spectrum, the median values for damage were 13.75% for oak and 9.5% for linden. The results also indicated that the number of sensors did not significantly affect the identification of the extent of red or violet damage zones. The application on poplar trunks showed that the tomograph is not suitable for very thin trunks with naturally thinner wood. Integrating these technologies into forestry operations could help create favorable conditions for the use of modern information technologies in conjunction with the sustainable management of forest resources.
Copyright (c) 2025 Miloš Gejdoš, Katarína Michajlová, Miroslav Němec (Author) https://creativecommons.org/licenses/by-nc-nd/4.0
TRANSMISSION OF VIBRATIONS AND NOISE FROM THE PRIMARY SOURCE OF THE TANK WAGONS
The research, of which this article is a part, deals with the design, implementation and verification of the methodology of measuring the transmission of vibro-sound energy from the contact of the tread profile with the rail through the primary suspension blocks, side bearers, bogie pivot and brake system to the tank shell and measuring the generation of sound energy by the wagon bogie. It analyses the frequency distribution of vibro-sound energy of individual blocks (components) of the tank wagon and the intensity of vibration transmission by these blocks until the mounting of the tank shell. Using frequency spectra, the transmission loss of individual bogie blocks and tank at a maximum speed of 120 km/h is displayed. The measurement methodology, measured amplitudes and frequency distribution of vibrations and noise in motion are the basis for reducing the vibro-sound energy not only of the developed prototype tank wagon, but also of railway wagons with a similar bogie. As part of scientific research, the proposed methodology was also successfully applied to solving the dynamic load of high-speed spinning headstocks used in the textile industry.
Copyright (c) 2025 Stanislav Žiaran, Ondrej Chlebo, Ĺubomír Šoos (Author) https://creativecommons.org/licenses/by-nc-nd/4.0
ANALYSIS OF ACOUSTIC ATTENUATION SPECTRA OF PHOSPHATE ION CONDUCTING GLASSES BEFORE AND AFTER DEHYDRATION
In this paper, acoustic attenuation measurements are used to detect structural changes due to chemical processes related to dehydration. This paper presents the initial acoustic measurements conducted at a frequency of 13 MHz on a glass sample composed of 40Li2O-10BaO-50P2O5 (mol %) both in its non-dehydrated state and following hydration. The analysis revealed that the notable peak within the mid-temperature range was decreased after 1 and 3 hours of the dehydration process, and by the 6-hour, it was no longer present in the hydrated sample.
Copyright (c) 2025 Peter Hockicko, Karolína Pradeniaková, Francisco Munoz (Author) https://creativecommons.org/licenses/by-nc-nd/4.0
SOUND FREQUENCY SPECTRUM VERSUS LENGTH OF CLOSED ORGAN PIPES
In the history of the pipe organ, we can observe different pitch standards, which are connected to the musical aesthetics of the time or the intentions of the builder. These differences are often noted based on provenance, meaning the origin or location where the organ was made. Each historical period had its own aesthetic and technical requirements, which were reflected in the tuning and pitch of the organ. The retuning of organs occurred mainly at the turn of the 19th and 20th centuries, with a change in the intonation of these instruments. In the territory of Slovakia, this change primarily involved a shift from the original pitch of approximately 412 Hz to 440 Hz. This change, of course, affected mainly older instruments and was part of a broader process known as the romanticization of organs. This process marked a departure from the original sound ideal of the Baroque period and a transition to the romantic sound ideal. Study examines the limitations of tuning height for wooden closed organ pipes, specifically the Copula stop, which has undergone significant retuning and intonation adjustments in the past. By using a gradual retuning method, the research analyses the sound's frequency spectrum to determine the optimal tuning range. The results show that significant changes in tuning height can lead to substantial degradation in sound quality. The research emphasizes that ill-considered restorative modifications to the air column length of these organ pipes lead to undesirable and permanent changes in the instrument's sound characteristics.
Organ pipes, wood, sound, tuning, restoration
Copyright (c) 2025 Andrej Štafura, Ján Poničan, Štefan Nagy, Ľubomír Pavlík (Author) https://creativecommons.org/licenses/by-nc-nd/4.0
Acoustic and thermophysical properties of recycled materials based on newsprint
The paper deals with the acoustic and thermophysical properties of selected materials created from the recycling of newsprints with potential applications in the structural components of timber buildings. The samples for the study were produced by recycling paper in three forms: as pure paper, then with the addition of used coffee grounds, and then with the addition of rubber from crushed automotive tires. Based on the measurement of the Sound Absorption Coefficient (SAC) and Noise Reduction Coefficient (NRC), it can be concluded that these materials are among the less absorptive in terms of acoustics. The best results were achieved by the material made from newspaper mixed with coffee grounds (NRC is equal to 0.30), which can be classified into sound absorption class D. The other studied materials fall into class E, with an NRC of 0.20. From the perspective of thermophysical properties, the tested materials exhibit thermal conductivity coefficient values ranging from 0.083 to 0.103 W·m⁻¹·K⁻¹, indicating that they do not meet the thermal insulation properties commonly associated with standard insulating materials.
Copyright (c) 2025 Rastislav Igaz, Miroslav Němec, Miloš Gejdoš, Samuel Kočuta, Dagmara Bednárová (Author) https://creativecommons.org/licenses/by-nc-nd/4.0
ANALYSIS OF STEAM EDUCATIONAL ACTIVITIES FROM PRIMARY TO TERTIARY
One of the ways we can motivate young people is by implementing Children's Universities as a form of motivating young people for future studies in science and technology. Young people expect a wide use of information and communication technologies in education. They are eager to work actively and implement their own ideas. Children up to the age of 10 undoubtedly have a real but hidden interest in natural and technical sciences, they want to become scientists and explorers. However, after a few years of education at the primary level, the situation changes completely. Simple acoustic experiments included in the teaching from the lowest levels of the education system stimulate children from early childhood to explore and lead from initial play to subsequent experimentation and discovery of new knowledge. Initial playful experimentation that involves multiple child senses (hearing, sight, and touch) stimulates experimentation at the time of primary education and later at the time of secondary and tertiary education in technical universities motivates analysis and evaluation at higher levels of cognitive goals according to Bloom's taxonomy.
Copyright (c) 2025 Peter Hockicko, Gabriela Tarjányiová (Author) https://creativecommons.org/licenses/by-nc-nd/4.0
Long-Term Trends in Road Traffic Noise Exposure and Annoyance in a Model Region
Environmental noise, particularly road traffic noise, has been considered one of the most widespread environmental pollutants. The primary aim of this study was a 30-year longitudinal investigation of road traffic noise annoyance trends in a model region - Bratislava’s continuously monitored neighborhoods, with data collected at 10-year intervals. Using validated methods to assess noise annoyance and psychosocial well-being, along with direct sound level measurements, the study analyzed responses from 3,197 university students residing in exposed and control areas. Results showed a significant rise in traffic noise burden in exposed areas from 1989 to 1999 (LAeq=67.5 dB), a slight decrease by 2019 (LAeq=63.9 dB), and further reduction during lockdowns (LAeq=62.5 dB). At the control site, noise levels significantly decreased from LAeq = 50.2 dB in 2019 to LAeq = 46 dB in 2020. Road traffic noise annoyance initially rose sharply, with ORMH values increasing from 2.56 to 6.01 over the first 10-year interval, gradually declining to ORMH 3.26 by 2023. Despite this trend, road traffic noise annoyance remains a concern, highlighting the need for preventive measures and healthier urban transport solutions.
Environmental noise, Noise annoyance trends, Road traffic noise, University students, Bratislava region
Copyright (c) 2025 Lubica Argalasova, Alexandra Filova, Katarina Hirosova, Martin Samohyl, Jana Babjakova, Jana Jurkovicova (Author) https://creativecommons.org/licenses/by-nc-nd/4.0
THE ANALYSIS OF THE DYNAMIC LOADING OF HIGH-SPEED SPINNING HEADSTOCK COMPONENTS
The article deals with the effective design of vibro-diagnostics of sources caused by self-excited vibrations of a high-speed spinning headstock bearing generated by residual unbalance, the quality of production and assembly of high-speed spinning headstock components. It also analyses the dynamic load from external vibration sources, primarily from the guide and pressure pulleys of the drive belt, as well as the effect of the Eigen frequencies of the Eigen modes of the test equipment. The article suggests the possibilities of analysing the dynamic load of high-speed headstock bearings using diagnostic sensors and it also indicates the calculation of the sound power level from the vibration velocity of the high-speed spinning headstock and/or another analysed component. The aim of this article is therefore to contribute to the reduction of energetic, dynamic (vibration and noise) and economic demands using operational condition monitoring in the production of textile yarn by improving the performance properties of high-speed bearings of spinning headstocks, which form an essential part of spinning technology.
high-speed spinning headstock, diagnostic sensor, vibration and noise reduction, monitoring
Copyright (c) 2025 Stanislav Žiaran, Ondrej Chlebo, Ľubomír Šooš (Author) https://creativecommons.org/licenses/by-nc-nd/4.0
Generative artificial intelligence - AI, particularly language models, are transforming industries by automating content creation and enhancing human-computer interactions. The STEM education approach in our engineering program is crucial to develop skills and insights that complement and go beyond what language models can achieve. Students must be educated with a highly flexible STEM approach, as AI already can easily handle highly repeatable tasks at a fraction of the cost compared to employee salaries. Without this kind of education, they risk losing their jobs to automation. The aim of this work is to highlight the STEM approach in obtaining and simple processing of sound data using Raspberry Pi.
Copyright (c) 2025 Marian Janek, Peter Hockicko, Gabriela Tarjanyiová (Author) https://creativecommons.org/licenses/by-nc-nd/4.0
THE ACOUSTIC OF FATRA HOUSE OF ARTS IN ZILINA, SLOVAKIA
In this article, we present a concert hall of The Fatra House of Arts in Zilina Slovakia, describe the hall itself and examine the acoustical quality of the hall. The concert hall primarily serves for symphony, chamber orchestra and soloist but hosts various cultural and social events as well. The hall is being considered as acoustically exquisite space by many professional musicians and conductors all around the world for a long time. However, real measurement of the objective acoustical quality parameters, that could confirm the subjective assessment, has never been carried out. We per-formed the measuring and evaluated the reverberation-based, energy-based, spectral-based, and spatial impression-based objective criteria. The measured results of objective parameters prove the correlation with the recommended values of specialized literature for chamber orchestra performances.
Copyright (c) 2025 Peter Kasák, Roman Jarina, Maros Jakubec, Michal Chmulík (Author) https://creativecommons.org/licenses/by-nc-nd/4.0
COMPARISON OF GRAND PIANOS ANT. PETROF AND MISTRAL
This paper describes the measurement of two Petrof grand pianos: Ant. Petrof and Mistral. The goal was to compare their parameters, i.e. harmonic spectra, decay time, relative sound level, spectral centroids, and cumulative line spectra (CLS). The complete range of 88 tones (keys) was measured in the anechoic chamber of Petrof, where we used a play-bench for precision. The obtained data were analysed and put into comparison. This analysis was supplemented by a comparison of selected samples (keys A2 and A4 played in forte and piano dynamics) to samples of three competing brands (Shigeru Kawai, Yamaha, Steinway).
Copyright (c) 2024 Ondřej Jirásek, Tomáš Peloušek https://creativecommons.org/licenses/by-nc-nd/4.0
This paper is dealing with the issue of D1 motorway surface(s) modernisation from the noise point of view. The surfaces of the individual sections were consecutively and longterm measured by the CPX method. The four analytical maps of the D1 road surface noise 1) before modernisation (year 2013); 2) after the modernisation (one year after the road section was put into operation); 3) difference map of noise before and after the modernisation; and 4) noise map in 2022 are the results. The analyses and measurement results show that the original assumption of the Road and Motorway Directorate – 2 dB reduction in average noise level after modernisation – has been significantly exceeded. It has also been demonstrated that D1, after the modernisation, had a lower average noise level than the reference (comparative) value specified in TKP 7. Reference value is based on long-term measurements of similar surfaces throughout the Czech Republic.
Copyright (c) 2024 Vítězslav Křivánek, Petra Marková, Jan Machanec, Blanka Hablovičová https://creativecommons.org/licenses/by-nc-nd/4.0
THE ANALYSIS OF DYNAMIC EFFECTS FROM THE TRAIN SET AT DIFFERENT DRIVING SPEEDS
The article is devoted to the problem of measuring selected dynamic parameters at a driving speed of 160 km/h to 200 km/h. The article contains a theoretical introduction to the issue, further describes the real measurement of dynamic-acoustic parameters with subsequent evaluation and comparison of measured data and parameters. The conclusion includes a presentation of the obtained results, recommendations for other similar measurements and, in particular, recommendations for railway infrastructure managers.
analysis in the time and frequency plane
Copyright (c) 2024 Jaroslav Smutný, Dušan Janoštík, Jan Pazdera, M Štukavec https://creativecommons.org/licenses/by-nc-nd/4.0
ROOM ACOUSTIC MEASUREMENT METHODS IN THE PAST, PRESENT AND FUTURE, INCLUDING THE IMPORTANCE OF THE ISO 3382 SERIES
The measurement of reverberation time in a room was introduced by W.C. Sabine a few years before 1900 with the purpose to handle acoustic problems in a lecture theatre. The sound source was organ pipes at the seven octave frequencies from 63 Hz to 4000 Hz. Later, the measurements were greatly improved by using interrupted white noise emitted by a loudspeaker and a microphone connected to a level recorder that could display the decay curve. This led to the first international standard on reverberation time measurements in 1963, intended for laboratory measurements of the sound absorption coefficient of materials. In 1975 appeared another international standard intended for reverberation time measurements, primarily in rooms for speech and music. A revision in 1997 introduced the impulse response as a basis for room acoustic measurements. This opened for derivation of other room acoustic parameters than the reverberation time, and this again led to a better understanding of how to design good rooms for music and speech. Some types of rooms are not sufficiently characterised by the reverberation time, and for that reason a new standard appeared in 2012 with a measurement method specifically intended for open-plan offices. Future development of room acoustic measurements may include faster and more reliable methods, better methods to overcome problems at low frequencies, a method to handle the influence the high-frequency problem of varying temperature and humidity of the air, and new ways to derive three-dimensional information on the sound reflections in a room.
Copyright (c) 2024 Jens Holger Rindel https://creativecommons.org/licenses/by-nc-nd/4.0
ACOUSTIC CHARACTERISTICS OF ROAD SURFACES
The article is focused on the tyre/road noise and vibration measurements of the motorway network in the Czech Republic between 2012 and 2020. Three different surfaces were measured, namely a conventional stone mastic asphalt pavement (SMA 11S) and two cement concrete pavements with different treatments – burlap drag and exposed aggregate. A basic statistical analysis of the noise values in different years after laying was performed. Cement concrete treated by burlap drag method has lower noise values than SMA 11S. This is to be expected as burlap drag method is considered a low-noise cement concrete treatment. However, it has worse skid resistance properties and so the exposed aggregate cement concrete (EACC) began to be used. SMA 11S and EACC have very similar noise levels in all years tested, suggesting that they behave acoustically in the same way. Vibrations were investigated during field measurements with an accelerometer mounted on the CPX trailer. The noise and vibration results could thus be compared with each other. There is a positive correlation between them.
tyre/road noise, stone mastic asphalt; exposed aggregate cement concrete; close proximity method (CPX)
Copyright (c) 2023 Petra Marková, Vítězslav Křivánek, Blanka Hablovičová, Jan Machanec https://creativecommons.org/licenses/by-nc-nd/4.0
This paper describes the innovation of Dreadnought guitars, especially braces on top plate. The goal was to increase the dynamic range of the instruments, not only in strength but also in spectral spread. The prolongation of tones in the Sustain and Release phases was also important. Mechanical and acoustic properties of instruments from Furch Guitars' production were measured (Chladni figures, frequency response), numerical simulation of innovated top plate in program ANSYS was prepared (by the matrix) and the changes in organisation of ribs were proposed as following. The new samples of innovated Dreadnought guitars were produced by the factory, again measured, analysed and evaluated.
Copyright (c) 2023 Ondřej Jirásek https://creativecommons.org/licenses/by-nc-nd/4.0
DETERMINATION OF THE ACOUSTIC POWER LEVEL EMITTED BY A MACHINE COMPONENT BY MEASURING VIBRATION
The article applies a methodology for determining the acoustic power of air-borne sound which is generated by the vibration of machinery components or the machine itself. The calculation of the acoustic power level is realized by measuring the vibration acceleration and integrating it to the vibration velocity of the rigid surface of the machinery or its component. The methodology is verified when determining the acoustic power level of operated spinning headstocks on a test facility. Undesirable noise emissions of spinning headstock bearings, as well as their operating condition, can be monitored by measuring kinematic parameters, measuring vibration acceleration and its subsequent integration. The vibration velocity was used to determine the A-weighted level and Z-weighted level of the acoustic power and at the same time to evaluate the operating condition of the two selected spinning units. The article also evaluates the importance of the correct choice of the measuring point of the analyzed spinning headstock on the test equipment when determining the level of acoustic power, which has a decisive influence on the uncertainty of the measurement.
Copyright (c) 2023 Stanislav Žiaran https://creativecommons.org/licenses/by-nc-nd/4.0
Acoustic Firefighting Method on the Basis of European Research: a review
In the past few years, there has been a search for new flame extinguishing methods that are both cost-effective and environmentally friendly. This article presents a detailed analysis of contemporary techniques for suppressing flames, including the use of fire-resistant materials, traditional firefighting agents, and eco-friendly acoustic firefighting. Among these methods, the acoustic approach seems particularly promising. Unlike chemical products, acoustic waves are safe for the environment, making them an attractive option for extinguishing flames. The article focuses on using acoustic waves to put out fires, taking into account the wave parameters and components. The effectiveness of this method is evaluated and compared to other techniques.
Acoustic Extinguisher; Acoustic Firefighting; Electrical Engineering; Flame Extinguishing; Fire-Resistant Materials; Fire Suppression
Copyright (c) 2023 Jacek Lukasz Wilk-Jakubowski https://creativecommons.org/licenses/by-nc-nd/4.0
OPTIMUM SOUND PROPAGATION IN OCEAN: THE COMPARISON BETWEEN NORMAL MODE AND EMPIRICAL FRANCOIS-GARRISON FORMULA
There are not only theory but also the empirical formula to deal with the problem of sound propagation in ocean. As such the Normal mode and Francois-Garrison are typical methods. Optimum sound propagation in ocean is the way we unify these two methods. In this paper, we investigate the transmission losses of both Normal mode and Francois-Garrison at some frequencies (170Hz, 800Hz, 100 KHz) at shallow water conditions (Tonkin gulf). The calculated and simulation results show that the optimum is achieved when the Normal mode is used at low frequencies whereas the Francois-Garrison is used at high frequencies.
Copyright (c) 2023 Tran Cao Quyen https://creativecommons.org/licenses/by-nc-nd/4.0
THE VIBRATION MEASUREMENT USING MICROCONTROLLERS
The contribution is devoted to the issue of measuring vibrations and possibly also noise using microcontroller technology. The contribution contains a theoretical introduction to the issue, and further describes the practical hardware implementation of the measuring system, the basis of which is a suitable microcontroller. Part of the contribution is also an analysis of the appropriateness of using such a measurement technique for application specifically in the field of railway constructions and buildings. The conclusion includes recommendations for other workplaces that would like to use this method of measurement.
Vibration, microcontroller, time domain analysis and frequency plane, identification of selected harmful phenomena, railway line.
Copyright (c) 2023 Jaroslav Smutný, Dušan Janoštík, Radovan Rímský, Petr Iunishchenko https://creativecommons.org/licenses/by-nc-nd/4.0
NOISE REDUCTION OF AIR DISTRIBUTION GRILLES USING 3D PRINTED INFILL STRUCTURES
The aim of this research is to reduce the noise level of air distribution grilles using 3D printed infill structures. The grilles are installed on a newly developed autonomous ventilation system, which is used for decentralised ventilation of e.g., school classrooms. Several supply and return grilles with functional gyroid and honeycomb shaped infill structures were created and subsequently printed on an FDM 3D printer. Based on measurements and analysis of the maximum sound pressure levels at different microphone positions around the system and at different airflows, the combination of grilles with the greatest noise reduction was selected. The research is complemented by other data such as spectral analysis of the noise, measurement of the airflow velocity through the grilles and measurement of the room reverberation time. Significant noise reduction was achieved by using the proposed grilles and further conclusions were drawn. 3D printing technology proved to be a very useful tool in this case.
Copyright (c) 2023 David Svoboda, Petra Berkova, Frantisek Vlach, David Beckovsky, Milan Gabzdyl, Martin Deutsch https://creativecommons.org/licenses/by-nc-nd/4.0
Testing a Novel Hybrid Spiral Microphone Array designed for Performance and Portability
In this investigation a novel hybrid spiral microphone array system is designed and constructed to maximize the overall performance of the array under the constraint that the array must be portable and capable of being transported in a small hatchback vehicle. Several microphone array designs are considered before settling on a modified Fermat spiral with microphones located exclusively on the axes of the array, enabling the array to be quickly disassembled into a small number of sections, transported to a remote location, and then re-assembled. The performance of the new microphone array is tested against an existing microphone array that was also designed for portability but with a more conventional logarithmic spiral design. The resolution of the new hybrid spiral array is found to greatly exceed the resolution of the conventional portable microphone array.
Copyright (c) 2023 Matthew Aldeman, Jin Jo https://creativecommons.org/licenses/by-nc-nd/4.0
As far as underwater source localization is concerned the Matched Field Processing (MFP) is an effective method. Floating ship localization, submarine localization in military section and fish finding in civilization are considered as the main application of MFP. Besides, determining environmental parameters such as sound speed profile, bottom topography and array tilt are also developed. Some methods such as empirical mode decomposition, adaptive MFP, compressive MFP and especially stochastic MFP using Riemannian geometry (RMFP) have been introduced recently in order to increase MFP’s reliability and resolution. It seems that the RMFP is the strongest candidate for the future development of MFP since it is inherited the strong foundation of both MFP and Riemannian Geometry. Surprisingly, not only the nature of curvature of sound wave but also the nature of MFP are exploited in RMFP. The aim of this monograph is introduce RMFP by considering the Riemannian distance instead of Euclidean distance. Two approaches of RMFP construction, i.e., isometric appings and direct Riemannian distance calculation are introduced. The organization of this monograph is as follows. Two first chapters of this monograph revised the reader about the essential meaning of Gauss Curvature, Geodesic equation, iso-metric mapping in Riemannian Geometry and the state of the art of MFP. Chapter 3 presents Riemannian MFP. Chapter 4 concludes the monograph with discussions about the performance of MFP. This monograph is designed for graduated students, scientists and senior engineers who working in the field of underwater acoustic engineering. We would like to thanks SACLANTC for providing access of SONAR array data. We also express our gratitude to University of Engineering and Technology (VNUH) for partial financial support this monograph. Finally, I deeply express my appreciate to my family, especially my father for their patient and love to me.
Copyright (c) 2022 Quyen Tran Cao https://creativecommons.org/licenses/by-nc-nd/4.0
PSYCHOLOGICAL ASPECTS IN (MICRO)INTERVALS OF THE JUST INTONATION SYSTEM
This study presents the results of research on the psychological aspects of exactly calculated just intonation intervals, which was performed in the form of a listening test. These micro-interval nuances (śruti) are attributed specific emotions or feelings in ancient Indian music-theoretical texts, just as in the European tradition, various extra-musical qualities have been attributed to different intervals or modes since the Antiquity. The purpose of the research was therefore to try to map the psychological aspects of the selected intervals and to verify whether the respondents agreed on them. In contrast to similar research testing tempered intervals, here we are dealing with precisely tuned concords of characteristic intervals of just intonation systems (5-limit and 7-limit just intonation), realized in the form of sustained drones. The results of this research show that listening to isolated sustained concords can induce a wide range of responses in the listener, which are identical or similar for a significant number of respondents. Moreover, in some cases, the reactions to a given interval/emotion combination coincide or resemble the characteristics given by Indian or European traditions. All the results of the research have been summarized in a table which can serve practical purposes.
just intonation, microintervals, drone music, La Monte Young, hindustani raga, shruti
Copyright (c) 2022 Tomáš Reindl, Viktor Hruška, Marek Frič https://creativecommons.org/licenses/by-nc-nd/4.0
THE LABORATORY TESTING OF RAIL FASTENING BY INERTIAL ELECTRODYNAMIC EXCITER METHOD
The paper is devoted to the use of an inertial electrodynamic exciter in laboratory testing of a rail fastening sample. The exciter of Tira Company was integrated into a control system from Vibration Research Company for testing purposes. The paper includes a discussion of the motivation for using the excitation system in laboratory testing, as well as a description of the characteristics and capabilities of dynamic excitation of structures, including a proposal of methods of analysing measured data. The Vossloh rail fastening sample was used for the purpose of the article. The contribution also includes a comparison of the vibration parameters of the tested structure and recommendations for other workplaces that would like to use a similar excitation system in their vibration experiments.
Vibration, vibration acceleration, electrodynamic exciter, excitation of rail fastening structures, time and frequency domain analysis, time-frequency methods
Copyright (c) 2022 Jaroslav Smutný, Lubboš Pazdera, Dušan Janoštík, Radovan Rimsky, Iunishchenko Petr https://creativecommons.org/licenses/by-nc-nd/4.0
THE ACOUSTIC FEATURES AND MUSIC-CULTURAL CONTEXTS OF CONCERT AND THEATRE HALLS IN SLOVAKIA - ZICHY PALACE, THE SLOVAK NATIONAL THEATRE
This study deals with spatial-acoustic research on two buildings in Bratislava, built in two different historical periods, with a significantly different primary function in terms of the musical life of the town. The Opera and Ballet Hall of the Slovak National Theatre is a relatively new building with a relatively short concert history. The concert life of the Concert Hall of Zichy Palace dates back to the 18th century and has an extremely rich concert history. The present study is devoted to describing the historical and cultural contexts, while also investigating their acoustic properties. The subject of the acoustical research is the description of the basic parameters – reverberation time T, clarity C80, interaural correlation coefficient IACC and spoken speech intelligibility measure STI.
field acoustics, concert halls, cultural heritage
Copyright (c) 2022 Pavol Brezina, Alena Čierna, Michal Jarabica, Peter Zaťko https://creativecommons.org/licenses/by-nc-nd/4.0
ASSESSING THE IMPACTS OF ROAD NOISE IN RELATION TO RESIDENTIAL AREAS AND ECONOMIC COSTS THROUGH MODELLING
This paper focuses on noise modelling and the assessment of road noise impacts in relation to residential areas and economic costs using modelling. The intention of the whole project and the authors' work is to contribute to the determination of changes in road noise levels for relevant decision-making processes with direct applicability in social sciences (regional development, sociology, demography, economics) related to health risk assessment (public health). The longevity, noise reduction levels and external cost changes of using low noise roads should therefore be appreciated. The purpose is to remove the identified disparity and to make publicly available, through a certified methodology, the data needed to assess the long-term effects of noise pollution from low-noise roads for use by regional development, thus contributing to the strategy of Directive 2002/49/EC.
Copyright (c) 2022 Vítězslav Křivánek https://creativecommons.org/licenses/by-nc-nd/4.0
Diffraction of a Spherical Wave by a Hard Half-Plane: Polynomial Formulation of the Edge-Diffracted Field in the Frequency Domain
The problem of diffraction of a spherical sound wave by a thin hard half-plane is considered. The expression of the total field at any position in the space around the half-plane is composed of two geometrical components and a third one which originating from the edge of the half-plane. This paper takes the expression of the edge-diffracted field due to a sound doublet, as formulated in the Biot-Tolstoy theory of diffraction, BTD, but rearranged for the Dirac-like pulse by Medwin. The present paper presents a development in the frequency domain of the Fourier transform of the exact expression of the edge-diffracted field as given in the time domain. This solution is composed of a serial development, expressed in simple trigonometric integral functions, and which away from the geometrical optics boundaries shows a quite rapid convergence to the numerical Fourier transform of the exact time-domain expression. The presented solution may be used as a good approximation in simulations and in real case predictions of sound scattering by thin straight-edged noise barriers.
Copyright (c) 2023 Djamel Ouis https://creativecommons.org/licenses/by-nc-nd/4.0