Loudspeaker Research Articles

О ВЛИЯНИИ МУЗЫКАЛЬНО-АКУСТИЧЕСКИХ ВОЗДЕЙСТВИЙ НА КЛЕТОЧНЫЙ ИММУНИТЕТ И ПЕРСПЕКТИВАХ БИОАКУСТИЧЕСКИХ ТЕХНОЛОГИЙ

This article reflects the results of an original study on the effects of musical-acoustic signals on cellular immunity. These studies are a logical continuation of a series of experiments with blood in an acoustic field in Vitro, begun in 2003. As a result, a new method was identified and patented for activating the growth of leukocyte mass and complex correction of blood composition using a regenerative algorithm of musical-acoustic influences. Its use made it possible to increase the number of neutrophils by 4.7 times, lymphocytes by 3.9 times, and immature granulocytes by 18.3 times within just one hour. In 2022, it was decided to conduct a pilot study of the dynamics of lymphocyte cell composition after acoustic interventions. Interest in cellular immunity is explained by its critical role in maintaining homeostasis, including in the fight against infectious and oncological diseases. The experiment used a special music therapy program, the broadcast of which was carried out in two ways: 1) direct intervention through sound speakers on venous blood in test tubes (in Vitro) and 2) separately, through receptive audio influence. When analyzing the results obtained, a tendency was revealed towards correction of the lymphocytic cellular composition of the blood with increased immune reactions: T-lymphocytes, natural «killer» cells, and strengthening the balance of active 4+ and cytotoxic 8+ immunity. An unexpected result should include activation of cellular immunity of comparable significance, which was detected with both methods of influence: direct exposure to sound in blood in test tubes and audio listening to the program. There is no doubt about the need for further research into the mechanisms of cellular and Psychophysiological reactions to musical and acoustic influences. It will become the basis for the development of effective methods of immunological correction and regenerative biotechnologies of a new generation, with subsequent widespread use in various fields of medicine, agriculture, and other spheres of society.

Evaluating the onset conditions of a thermoacoustic Stirling engine loaded with an audio loudspeaker

This paper aims to evaluate the onset conditions of a thermoacoustic Stirling engine loaded with a commercially available audio loudspeaker. The thermoacoustic engine converts supplied heat power into mechanical power in the form of sound, without any mechanical moving parts. The simplicity of the acoustical heat engine holds great promise for high reliability and low cost. By utilizing a readily available electromagnetic device, the engine can serve as a durable solution for practical applications. In this study, we assembled a commercially available moving-coil loudspeaker as a low-cost linear alternator for the thermoacoustic Stirling engine, enabling electric generation from supplied heat. We modeled the loudspeaker using linear control equations and experimentally calibrated its acoustic impedances to estimate the acoustic load. For the part of the thermoacoustic engine, we estimated its acoustic characteristics within the framework of the linear thermoacoustic theory. By solving the characteristic equation resulting from the engine loaded with the audio speaker, we estimated the operational point of self-sustained oscillations excited by the coupling of the loudspeaker and the thermoacoustic engine system. To validate the estimations, we tested a prototype of the combined system, comprising the loudspeaker and the thermoacoustic engine. The results highlight the necessity of precise calibration and accounting for complex geometries within the acoustic load for accurate theoretical estimations, especially when incorporating a commercially available loudspeaker into a thermoacoustic engine.

Design of coupled Helmholtz resonator with rectangular enclosure to mitigate low frequency noise in recording booths

This study summarizes theoretical and experimental findings for low frequency noise mitigation in small recording booths using coupled Helmholtz resonators. The room acoustical resonance modes were identified using ANSYS simulation software for the recording booth. An experimental setup validated the existence of the different low frequency modes and variation from theoretical results due to the enclosure wall's surface material. Microphone and speaker system were used to measure the room frequency response at the resonant frequencies. Piezoelectric sensors were placed at different positions within the room to determine the location of resonance peaks and the optimized position for the coupled Helmholtz resonator. The effects of damping on the Helmholtz resonator frequency response and deviation from theoretical design formulae were explored. The resonator apparatus proved to attenuate noise to half as loud in the selected low frequency range within the recording booth.

Effect of masker selection schemes on the perceived affective quality of soundscapes: A pilot study

The perceived quality of a given soundscape may be improved by adding "pleasant" sounds via a speaker or electroacoustic system to the existing soundscape as maskers. Ideally, the choice of sounds should be automated to minimize the time and labor required to maintain such a system. Hence, we investigate the effect of several automated masker selection schemes on improving the ISO Pleasantness of urban soundscapes in a controlled laboratory environment. An ambisonic recording and 360-degree video of a location exposed to traffic noise was made and reproduced via a stacked planar speaker array and virtual reality headset. Simultaneously, maskers from a fixed candidate pool were overlaid on the reproduced soundscape in one of the following methods: random selection across the entire pool, fixed selection based on results in the literature, random selection across a restricted pool based on model-agnostic analysis of a pre-existing dataset, and random selection across a restricted pool based on a deep neural network trained on a pre-existing dataset. We also investigated a control condition with no added maskers, and evaluated the results based on changes in ISO Pleasantness ratings given by participants to the soundscape under each masker selection scheme, relative to the control condition.

Brazilian Portuguese vowel discrimination by Nungon and Tashelhit speakers

The vowel system of speakers’ native languages are known to affect perception of vowels in foreign languages (Elvin et al., 2021). In a field-based behavioral experiment, we tested the perception of Brazilian Portuguese vowels (seven-vowel system) by speakers of the Papuan language Nungon (six-vowel system) and the Berber language Tashelhit (three-vowel system). 60 native speakers of Nungon and 38 native speakers of Tashelhit participated. The acoustics of Nungon vowels were previously analyzed using a 30-point analysis technique (Sarvasy et al., 2020). For the present study, we also analyzed Tashelhit vowels using the same technique. We then used discriminant analysis to analyze the relationship between speakers’ performance on the Brazilian Portuguese vowel discrimination task and the acoustics of vowels in their native languages. We present preliminary results of these analyses, and address their possible contributions to four areas: (a) description of the acoustics of under-described languages, (b) the relationship between native vowel systems and perception of foreign vowels, (c) methods for undertaking rigorous acoustic and experimental research in noisy, field environments, and (d) theoretical frameworks for phonetic learning such as the L2LP model (Escudero, 2005; van Leussen and Escudero, 2015).

A comparison of underwater speakers for fish playback studiesa).

Acoustic playback is a key method used to determine the behavioral significance of animal sounds, including fishes. This study presents the first comparison of the acoustic quality of underwater speakers for the playback of fish sounds. Seven underwater acoustic playback systems were tested for their ability to accurately reproduce the low frequency, pulsed, courtship sounds of a small fish, Tramitichromis intermedius (Cichlidae). Results indicated that in an aquarium with low ambient noise and at low amplitude playback levels (<120 dB re 1 μPa), the Clark Synthesis speakers were the best choice for playback at moderate distances (>20 cm), and that the Electro-Voice UW30 was the best speaker for short distance (<20 cm) playback of low frequency fish sounds. However, in aquaria with higher levels of ambient noise and at higher amplitude playback levels, the Clark Synthesis speakers performed best. However, none of these speaker systems reproduced a high-fidelity quality fish sound. It is important when using underwater speakers for behavioral studies that there is a careful assessment of the played back sound and comparison to the original sound.

Test of Time

Advances in testing are helping speaker system manufacturers more accurately predict the performance of their devices across their life cycle, says KLIPPEL.

A study on improving the sound radiation capability of stepped-plate parametric array loudspeakers

It is well known that Parametric Array Loudspeakers (PALs) produce highly directional audible sounds. However, their widespread adoption is hindered by their high cost, which is primarily attributable to the use of an array of ultrasonic radiator units. To address this issue, our research group introduced stepped-plate parametric array loudspeakers (SPPALs) in 2018. SPPALs utilize a single-structure directional ultrasonic radiator, featuring steps of half-wavelength thickness on the radiating plate. This design mitigates the problem of poor directivity, especially at high frequencies, caused by destructive interference resulting from the plate's flexural mode. Moreover, SPPALs can offer cost advantages compared to commercial PALs due to their single structure. However, understanding the vibration characteristics of SPPALs in relation to sound radiation performance is quite challenging due to their various design parameters. In this study, we present an analytical approach that offers a quantitative method for enhanced sound radiation capability. We present a simplified vibration model (SVM), which enables an efficient design process based on a comprehensive analysis of vibration characteristics. By minimizing reliance on finite element method (FEM) simulations, our method expedites the design of various directional speaker systems.

Соматический код «голова» в китайской фразеологии

The aim of the study is to identify the semantic characteristics of the somatism “head” as a part of Chinese phraseological units. The scientific novelty of the study lies in the fact that the work considers the somatism “head” as a cultural code that not only represents the essential characteristics and qualities of a person, but is also a historically conditioned, culture-specific element of the semiotic system of native Chinese speakers. The paper presents a contextual and semantic analysis of Chinese phraseological units selected by the continuous sampling method; identifies the key semantic groups (macro-fields) that determine the functional features of the head attributed to it in Chinese linguoculture due to a metaphorical and metonymic reinterpretation. It is determined that through the body code “head”, the evaluative description of a person is actualised, value parameters and reference points of Chinese culture are conveyed. As a result, the following is revealed: the semantics of the phraseological units with the somatic component “head” reflects the national and cultural specifics of the phraseological worldview of the Chinese; the head is the locus of emotions, mind, character of a person; the head represents ideas about a person’s appearance, longevity, integrity, leadership (victory).

"Cancer Education on Wheels," a Novel Cost-Effective Method in Creating Awareness in the Community: a Pilot Study.

Cancer education raises disease awareness, the value of early identification and importantly the need for prompt screening and treatment when diagnosed. In this study, an effort was made to understand how well a unique cancer education program, "Cancer Education on Wheels," transfers knowledge in general public in society. The community was shown prerecorded cancer awareness videos using a TV monitor, CD player, and speaker system mounted on an eight-seat Toyota Innova. Before and after seeing the video presentation, consenting volunteers filled out questionnaires asking about demographics and understanding of cancer. Frequency and percentage calculations were done on the demographic information and a Wilcoxon signed-rank test was run on the overall subject score. Data was stratified based on demographic information and compared by applying Kruskal-Wallis test and Mann-Whitney test. p values under 0.05 were regarded as significant. A total of 584 people completed the pre-test and post-test questionnaires. The Wilcoxon signed-rank test revealed a difference between the pre-test and post-test (3.29 ± 2.48 vs. 6.78 ± 3.52; P = 0.0001). The pre-test results showed that volunteers between the ages of 18 and 30; men; students; urban residents; single volunteers; graduates; people who had known a person/or family member with cancer; and people who were aware of the suffering cancer causes had a high baseline knowledge of cancer (p = 0.015 to 0.001). The post-test results show that participants who had less baseline scores like housewives and unemployed people performed better (p = 0.006 to 0.0001). The findings unambiguously demonstrated that "Cancer Education on Wheels" was successful in raising participants' awareness of cancer signs and screening. Additionally, the findings showed that volunteers who were aged, married, housewives, and unemployed had higher scores. Most importantly, this approach to cancer education is simple to organize and carry out in a local setting. It is also affordable and simple to execute using readily available technological equipment and manageable logistics. According to the authors' knowledge, this is the first study to use "Cancer Education on Wheels" to spread awareness of cancer throughout the neighborhood especially in budget constrained areas.

Experimental and theoretical determination of the speed of sound in lung parenchyma of rabbits

The purpose of the study was to develop an experimental-theoretical method for determining the speed of sound in the lung parenchyma. The method is based on the measurement of the characteristics of the impedance of the Helmholtz resonator, that contains lungs under study. The input impedance of the Helmholtz resonator corresponds to the parallel connection of the lung impedance and a resonator. The modified two-microphone method is used to measure the resonant frequency and input impedance response of the product of the resonator chamber volume (lungs). The experimental system consisted of a loud speaker, a wave guide, two microphones for the measurement, and the end empedance node in the form of a connecting tube extended to the inside of the Helmholtz resonator with specified geometric characteristics. When the lungs are added to the Helmholtz resonator, the frequency increases, but not linearly with the decrease in their volume, indicating that the speed of sound is abnormal low in the lung parenchyma. The difference between the calculated and measured resonant frequencies is used to determine the speed of sound in the lung parenchyma. The measurements were carried out on air and collapsed lungs of 8 apparently healthy rabbits. Two variants of sound transmission in the lung parenchyma, corresponding to isothermal and adiabatic processes, are considered. The results of measurement and calculation demonstrate that the speed of sound in the lung parenchyma of an apparently healthy rabbit is 21-22 m/s, what is in accord with modern theoretical concepts.

Linguistic Phenomena in the Context of Psycholinguistic Analysis

In the article, analysis and generalization of theoretical and experimental data on the study of human speech behavior allow us to conditionally distinguish the following three aspects in the structure of language ability: the language mechanism or the ability to master a language (native and / or foreign), the language organization of a person or mental representation and organization in the mind of the speaker systems of signs of a natural language and the norms of their communication, the speech mechanism or the ability to carry out speech activity - to produce and perceive speech statements.

ANOPHONE: An Annotation Tool for Phonemes and L2 Annotation Systems for Czech

Abstract The goal of this text is the presentation of the ANOPHONE annotation system, which allows for the management and annotation of speech data to develop a tool for the automatic transcription of speech of non-native speakers of Czech. This system is currently designed for annotations on the segmental level of recordings of non-native speakers of Czech, with the aim to train automatic speech recognition (ASR) models used in this tool. After an introductory section that discusses the use of technology in pronunciation teaching and mentions some of the e-learning applications for teaching the pronunciation of second languages (L2), we address both general and more specific aspects of speech data annotation to train ASR models and mention attributive and synthetic segmental systems of speech data annotation for Czech as L2. We also briefly introduce the annotation system of non-native speakers of Czech called BV1, which is used for testing the ANOPHONE tool. The main part of this text focuses on presenting the annotation tool itself, while the conclusion describes the experience of testing the speech data annotation tool using BV1 annotation system for Czech as L2.

Speaker Counting Based on a Novel Hive Shaped Nested Microphone Array by WPT and 2D Adaptive SRP Algorithms in Near-Field Scenarios.

Speech processing algorithms, especially sound source localization (SSL), speech enhancement, and speaker tracking are considered to be the main fields in this application. Most speech processing algorithms require knowing the number of speakers for real implementation. In this article, a novel method for estimating the number of speakers is proposed based on the hive shaped nested microphone array (HNMA) by wavelet packet transform (WPT) and 2D sub-band adaptive steered response power (SB-2DASRP) with phase transform (PHAT) and maximum likelihood (ML) filters, and, finally, the agglomerative classification and elbow criteria for obtaining the number of speakers in near-field scenarios. The proposed HNMA is presented for aliasing and imaging elimination and preparing the proper signals for the speaker counting method. In the following, the Blackman-Tukey spectral estimation method is selected for detecting the proper frequency components of the recorded signal. The WPT is considered for smart sub-band processing by focusing on the frequency bins of the speech signal. In addition, the SRP method is implemented in 2D format and adaptively by ML and PHAT filters on the sub-band signals. The SB-2DASRP peak positions are extracted on various time frames based on the standard deviation (SD) criteria, and the final number of speakers is estimated by unsupervised agglomerative clustering and elbow criteria. The proposed HNMA-SB-2DASRP method is compared with the frequency-domain magnitude squared coherence (FD-MSC), i-vector probabilistic linear discriminant analysis (i-vector PLDA), ambisonics features of the correlational recurrent neural network (AF-CRNN), and speaker counting by density-based classification and clustering decision (SC-DCCD) algorithms on noisy and reverberant environments, which represents the superiority of the proposed method for real implementation.

Long-distance anti-interference self-feedback regulating fire emergency speaker system

Modern building groups are getting larger and larger, and the lines are getting longer and longer, which directly leads to two major problems. One is that the volume of loudspeakers at the end of the line cannot meet the requirements of normal use. If the power is increased, the loudspeakers near the line will howl and self-excite too much. Second, the power of the power amplifier and the number of loudspeakers cannot be matched exactly. It is urgent to develop fire-fighting loudspeakers or emergency broadcasting systems that can be applied to long-distance transmission, having strong anti-interference ability, and can realize automatic adjustment through feedback. This paper develops a set of intelligent fire broadcast system based on distributed power amplifier, which can realize the following functions: it can connect with other platforms and systems through the big data platform, realize cross-platform, cross-system real-time long-distance playback of the broadcasting system, and solve the problem of terminal volume. By switching channels, power control, etc. Using the near-end strategy optimization algorithm based on tailoring, the optimal joint interference avoidance strategy of the system is obtained to solve the problem of environmental noise interference. Based on the deep reinforcement learning algorithm, the problem of matching the power amplifier power and the number of speakers is solved.

Low-cost automated call box system to conduct playback experiments for wildlife research and management

Acoustic cues (e.g., vocalizations or ‘calls’ in wildlife) may effectively change social behavioral patterns in certain species. There are very few published papers on how to create a device at a low cost that can automatically reproduce acoustic cues to carry on wildlife playback experiments or management. We developed the Automated Call Box (ACB) based on an open-source Arduino-compatible microcontroller that attaches to a speaker system and costs less than the most common game caller used by researchers. The unit helps test the influence of social information on habitat choices and has other management applications. We field-tested the ACB to assess the effect of conspecific vocalizations cues on the habitat settlement and to increase the detectability of songbird species. We describe in detail the costs of the materials to build this type of system as a reference for further research. Our ACB allows researchers to conduct experiments on wildlife in inclement weather and complex environments, even in remote locations, with minimum or no necessity for the researcher to be present to reset the equipment.

Prevention of False Data Injection in Dataset using ML and DL

IoT is an interconnected and allotted network of embedded systems communicating through wired and wireless communication technology. It is defined as network of physical objects or things empowered with limited computation storage and conversation capabilities as well as embedded with electronics (sensors and actuators). Nowadays there are literally masses of hundreds of Internet of things (IoT) gadgets easily available to the customers. those consist of security cameras, smart home and smart speaker systems, smart toys and infant monitors, drones, domestic appliances, routers and internet gateways, and basically some other hardware products which can transmit information and be controlled over the net. FDIA is an attack this will result in a catastrophic outcomes. False information injection attack can be executed in each dynamic and static datasets, as a present device we easily discover and prevent in a static environment. in which with the present machine even the dynamic records is made static after which detects FDIA’s. FDIA in a static environment is the existing machine, in which we seek to have few solutions for the FDIA in a dynamic environment or for time collection information. So, to enhance protection in dynamic environment is our proposed challenge towards FDIA and we create a brand-new version known as “PdD” model – Predictive Dynamic version. Proposed framework performs crucial role in live streaming records in terms of heterogeneous environment (dynamic nature). So, we use GRU set of rules because it offers better RMSE value than different AI algorithms. This detects every time there may be a few FDI attack.

Educational high school physics demonstration apparatus for acoustic landmine simulant resonance detection

This landmine “simulant” resonance detection demo was created in conjunction with a high school physics mentorship, using a variety of easily-accessibleequipment in order to demonstrate an important application of fundamental concepts of sound and vibration. A plastic tray (4 in. deep) contained a 3-in. diameter drum-like circular landmine simulant (1.5 in. high) with a thin acrylic top plate buried (1 in. deep) in a 3 in. layer of dry sifted masonry sand. A small accelerometer was place on the surface over the simulant. Airborne sound, a loud speaker chirp, with frequency slowly increasing over time, was created using a Mathematica® generated wav file played by the Raspberry Pi® computer. Sound excited the sand vibration that coupled to the top plate. The accelerometer generated a frequency response voltage, related to the sweep time. The Raspberry Pi® also played a role in implementing the A to D conversion, so that the frequency response near resonance was displayed as a voltage in a readable format. With this demo apparatus high school students will be excited by the fundamentals of wave propagation and concepts about resonance with regards to its real-life applications. [Specially inspired by James M. Sabatier’s research on acoustic landmine detection.]

Merger in Eivissan Catalan: an acoustic analysis of the vowel systems of young native speakers

AbstractThe vowel system of Catalan has been the focus of many studies, though work on the varieties spoken on the island of Eivissa (Ibiza) are scarce, with a single mention of the possible merger of the mid back vowels /o, ɔ/ (Torres Torres, Marià. 1983. Aspectes del vocalisme tònic eivissenc.Eivissa14. 22–23). The present article provides the first acoustic analysis of the vowel inventory of 25 young native speakers of Eivissan Catalan, with a focus on the realisations of stressed /ə, ɛ/, and the back mid vowels /o, ɔ/. We employed Pillai scores (Hay, Jennifer, Paul Warren &amp; Katie Drager. 2006. Factors influencing speech perception in the context of a merger-in-progress.Journal of Phonetics34. 458–484) to compare the possibly merged pairs /ə, ɛ/ and /o, ɔ/ to the fully-contrasting neighbouring pairs /e, ɛ/ and /o, u/. Our results show that all participants had considerable overlap of stressed /ə/ and /ɛ/, and all but one had considerable overlap of the back mid vowels, while the fully contrastive pairs (/e, ɛ/ and /o, u/) showed almost no overlap.

“I Wanna Sound Like You so Why Don’t I?” Expectations Versus Reality for Egyptian Learners of English

We all come with our preconceived notions. The expectations of 180 Egyptian learners of EFL at a private institution in Egypt revealed that the majority of learners expect to sound like native speakers by the end of the 3-month course and teachers to do all the work and provide them with a textbook. This could be attributed to the learners’ previous experience with language learning. Still, teachers need to be able to anticipate and fulfill their needs.