Sound Frequency Research Articles

A Study on the High Reliability Audio Target Frequency Generator for Electronics Industry

The frequency synthesizer performs a simple function of generating a desired frequency by manipulating a reference frequency signal, but stable and precise frequency generation is essential for reliable operation in mechanical equipment such as communication, control, surveillance, medical, and commercial fields. Frequency synthesis, which is commonly used in various contexts, has been used in analog and digital methods or hybrid methods. Especially in the field of communication, a precise frequency synthesizer is required for each frequency band, from very low-frequency AF (audio frequency) to high-frequency microwaves. The purpose of this paper is to design and implement a highly reliable frequency synthesizer for application to a railway track circuit systems using AF frequency only with the logic circuit of an FPGA (field programmable gate array) without using a microprocessor. Therefore, the development trend of analog, digital, and hybrid frequency synthesizers is examined, and a method for precise frequency synthesizer generation on the basis of the digital method is suggested. In this paper, the generated frequency generated by applying the digital frequency synthesizer using the ultra-precision algorithm completed by many trials and errors shows the performance of generating the target frequency with an accuracy of more than 99.999% and a resolution of mHz, which is much higher than the resolution of 5 Hz in the previous study. This highly precise AF-class frequency synthesizer contributes greatly to the safe operation and operation of braking and signaling systems when used in transportation equipment such as railways and subways.

Experimental study on the effect of sound stimulation on hearing and behavior of juvenile black rockfish (Sebastes schlegelii)

Assessing the potential impacts of wind farm noise on fish is a crucial aspect of Environmental Impact Assessment (EIA) studies. There is increasing evidence of disturbances and effects on hearing and behavior in animals. The black rockfish (Sebastes schlegelii) is a commercially valuable rocky reef fish native to East Asia. However, empirical studies that measure the actual consequences are lacking. In this study, we used auditory evoked potentials (AEP) to assess the effects of dominant frequency noise emitted by offshore wind farms on the auditory sensitivity, hearing threshold, swimming, and feeding behavior of juvenile black rockfish. The experimental findings revealed that the most sensitive sound frequency was 200 Hz, with the lowest hearing threshold recorded at 86.4 ± 3.4 dB re 1 μPa. Following 3 and 7 days of exposure to 200 Hz noise at 110 dB, threshold shifts in black rockfish reached 19.0 dB and 13.3 dB, respectively. During the subsequent recovery phase, these shifts decreased to approximately 9.8 dB after 3 days, respectively. The noise-exposed group exhibited higher swimming duration, moving distance, and caudal fin swing frequency compared to the control group without noise exposure. Furthermore, noise prolonged the feeding rate of black rockfish. Our findings provide the first evidence of noise-induced temporary threshold shift and behavioral disturbances in juvenile black rockfish, implying potential fitness consequences associated with noise pollutant.

Bionic Luminescent Skin as Ultrasensitive Temperature-Acoustic Sensor for Underwater Information Perception and Transmission.

Bioinspired artificial luminescent skin (L-skin) integrated with multiple sensing functions significantly promotes the development of smart devices. It is considerably challenging to realize underwater sensing technologies. Here, a sharkskin-inspired Eu@HOF-TJ-1@TA L-skin (1) is prepared for both temperature and sound sensing. 1 is an ultrathin and flexible temperature sensor, in 298.15-358.15 K, exhibiting ultrahigh maximum relative sensitivity (97.669% K-1 ) and low minimum uncertainty (0.000952 K). The temperature response mechanism is analyzed deeply. As a waterproofing acoustic sensor, 1 can monitor sound in both air and water with the greatest sound response frequencies of 400 and 300Hz in air and water, respectively. The maximum sensitivities of 1 in air and water are 6593765.2 and 1346124.5 cps Pa-1 , respectively. The response times of 1 in air and water are as fast as 20 and 10ms. The sound response processes of 1 in air and water are simulated by finite element simulation. Moreover, by using sharkskin-inspired 1, the actual water temperature can be monitored, and a series of water sound information can be recognized by using an artificial neural network. This work proposes a sharkskin-inspired L-skin for temperature and acoustic sensing and promotes the development of underwater sensing technology with high performances.

Sound Absorption Properties of the Patented Wood, Lightweight Stabilised Blockboard

Abstract It is well known that wood tends to shrink and swell as the relative humidity of the air changes. There have been, and still are, attempts to make dimensionally stable wood panels such as Dendrolight®. The physical-mechanical, operational, including acoustic, properties of this material have been significantly improved compared to traditional wood-based panels. However, the production of this material requires very specific processing equipment and a large energy investment. The developers of this material in Latvia invented and patented wood, Lightweight Stabilised Blockboard (LSB). In order for this material to be used in the production of various products, it is necessary to clarify its characteristic, technological, as well as operational properties. The study gathers information about the sound absorption properties of various natural and wood materials, characteristics, and the sound absorption of the studied material at different sound frequencies. The reviewed sources of information indicate that nowadays there are still problems in sound conduction and absorption and isolation issues are being addressed in building acoustics. The production of samples and the determination of sound absorption were carried out using a developed methodology developed in accordance with regulatory requirements. The data obtained in the practical study were compared with the relevant indicators of the Dendrolight® and wood-based panels used for building structures and to determine their compliance with the requirements set forth in the standards ISO 10534-2 and ISO 11654. Research data show that LSB corresponds to E sound absorption class in some of the investigated frequencies.

Optimization design and analysis of the broadband acoustic absorber of the microperforated panel with an interpolated straight tube

The microperforated panel (MPP) structure is widely used in the field of noise reduction. The traditional MPP structure has a fixed absorption peak, and the optimized MPP structure has an improved absorption band, but the frequency range of the absorption is not ideal. For the design of broadband absorption in MPP structures, this paper presents a MPP acoustic absorber structure (N-MH) with an interpolated straight tube (IST) designed for superior broadband acoustic performance. The N-MH structure combines the advantages of the MPP and the embedded necked Helmholtz resonator, as well as having a sub-wavelength thickness of only 60 mm, which is only 1/14th of the wavelength at the first resonant frequency. The N-MH structure is optimized based on the particle swarm optimization (PSO) algorithm. In comparison to traditional microperforated panel structures, the N-MH structure exhibits a significantly broader sound absorption frequency band. Additionally, we thoroughly investigate the factors influencing the mid-low-frequency sound absorption performance of the N-MH structure. Through theoretical prediction, simulation analysis, and experimental testing, it is verified that the N-MH structure has excellent broadband sound absorption characteristics in the frequency interval of 0–2000 Hz, and the percentage of sound absorption bands with absorption coefficients exceeding 0.9 can reach 78.2%.

A note on the audio sound power generated by a parametric array loudspeaker.

Understanding the sound power characteristics of parametric array loudspeakers (PALs) poses a unique challenge due to the nonlinear process involved. This work addresses this issue by employing the spherical convolution directivity model to obtain the far field intensity, which is then used to calculate the sound power radiated by a PAL. The results reveal that the audio sound power is approximately proportional to the square of the audio frequency and the aperture size, while inversely proportional to the ultrasound frequency. Additionally, the conversion efficiency from ultrasound to audio sound is found to be generally below 0.15% for typical configurations.

On a recording method for ambient sounds with a confidential speech

There are many reports that environmental noise in healthcare facilities affects patients and healthcare workers both physically and psychologically. To study the sound environment in hospital wards, it is necessary to analyze live sounds (conversations, sounds of daily life, alarms, etc.) generated by human activities. Recording in hospital wards, as in all healthcare facilities, requires the protection of personal information. Sound recorded in healthcare facilities may include conversations that people do not want to hear. Therefore, it is necessary to develop a recording method that solves confidentiality issues. We have already confirmed that by fragmenting recorded sounds at short time intervals, the time-averaged sound pressure level of 1/3 octave band frequency of the sounds does not change. This time we developed a new PC application that fragments and then stores the data without storing original sound data. We analyzed the time-averaged sound pressure level of 1/3 octave band frequency of fragmented speech and alarm sounds using this new application. The results showed that the time-averaged sound pressure levels of fragmented and non-fragmented sounds were almost the same.

Sound attenuation analysis of a honeycomb structure with extended necks

In this paper, a honeycomb structure metamaterial consisting of 95 necks that are attached to the perforated top panel is presented and its sound absorption coefficient and transmission loss are investigated using the finite element method. Helmholtz resonators are therefore created by each honeycomb cell (cavity) and the attached neck, which is protruding within each cell. The structure has therefore a high bending stiffness due to the honeycomb mechanical performance and constitutes a sound absorber based on the parallel assembly of multiple Helmholtz resonators. This study demonstrates the importance of properly designing the diameter and the length of each neck to create a broadband sound absorption. One resonant sound absorption peak is observed when all the necks are identical, and two absorption peaks are obtained using two different sets of neck parameters. When the number of different necks increases, the sound absorption frequency band improves and when the parameters of all the necks are different, resulting in a parallel assembly of 95 different Helmholtz resonators, the sound absorption frequency band broadens. The material design studied in this paper can be useful in various applications where available space is limited and high mechanical stiffness and noise reduction are required in one structural element.

Auditory masking based on automatic chord progressions using modulation conditions of critical bandwidth in diatonic chords for dental treatment sounds

The unpleasant noise is one of the important social problems because our quality of life is degraded by it. We have previously proposed the comfortable sound design method based on chord-forming with music theory for dental treatment sounds. The previously proposed method is difficult to apply various dental treatment sounds because that employs single chord progression. To solve this problem, we focus on the automatic generation of chord progression by using diatonic chords. In this paper, we propose an auditory masking method based on the automatic generation of chord progression using diatonic chords with the key determined from the peak frequencies of dental treatment sounds. The proposed method employs the modulation conditions of critical bandwidth in diatonic chords for comfort in the modulations. The proposed method can achieve suitable sound design for various dental treatment sounds by utilizing real-time key determination according to the peak frequency of dental treatment sounds. Finally, we confirmed the effectiveness of the proposed method through evaluation experiments.

Micro-perforated mufflers based on the Acoustic Black Hole effect

Attenuation of acoustic disturbance with compact and low-weight acoustical devices is a demanding requisite in industries such as vehicle exhaust mufflers, turbofan liners or ventilation systems. Acoustic Black Holes (ABH) is a concept that has been studied originally in the field of vibration control for the design of a structure based on a power-law thickness profiles along its edges. The idea of wave trapping and dissipation has been extended to the field of duct acoustics using compact devices that avoid blocking the air flow. Based on this idea, in this work we propose the study of a micro-perforated silencer that should prevent reflection and transmission of the sound waves over a wide range of audible frequencies. The use of micro-perforations over the facing cavities should help to extend performance towards the low frequency range. The acoustic behavior of the ABH is assessed from theoretical and numerical modeling. The performance can be greatly improved when the physical constituting parameters are optimized simultaneously. Particle swarm optimization is a computational method inspired by the behavior of natural systems that is able to provide a satisfactory solution with enhanced total dissipation.

High-order Bragg forward scattering and frequency shift of low-frequency underwater acoustic field by moving rough sea surface

Acoustic scattering modulation caused by an undulating sea surface on the space–time dimension seriously affects underwater detection and target recognition. Herein, underwater acoustic scattering modulation from a moving rough sea surface is studied based on integral equation and parabolic equation. And with the principles of grating and constructive interference, the mechanism of this acoustic scattering modulation is explained. The periodicity of the interference of moving rough sea surface will lead to the interference of the scattering field at a series of discrete angles, which will form comb-like and frequency-shift characteristics on the intensity and the frequency spectrum of the acoustic scattering field, respectively, which is a high-order Bragg scattering phenomenon. Unlike the conventional Doppler effect, the frequency shifts of the Bragg scattering phenomenon are multiples of the undulating sea surface frequency and are independent of the incident sound wave frequency. Therefore, even if a low-frequency underwater acoustic field is incident, it will produce obvious frequency shifts. Moreover, under the action of ideal sinusoidal waves, swells, fully grown wind waves, unsteady wind waves, or mixed waves, different moving rough sea surfaces create different acoustic scattering processes and possess different frequency shift characteristics. For the swell wave, which tends to be a single harmonic wave, the moving rough sea surface produces more obvious high-order scattering and frequency shifts. The same phenomena are observed on the sea surface under fully grown wind waves, however, the frequency shift slightly offsets the multiple peak frequencies of the wind wave spectrum. Comparing with the swell and fully-grown wind waves, the acoustic scattering and frequency shift are not obvious for the sea surface under unsteady wind waves.

Duration of the Archive: Soundscapes of Extreme Witnessing in Divya Victor’s Curb

This paper examines the significance of soundscapes in the Tamil American poet Divya Victor’s reconstruction of the archive of anti-South Asian violence in her acclaimed poetry collection Curb (Nightboat Books, 2021). Being a continuation of the poet’s investigation of the limits of conceptual and “documental” poetics (Michael Leong), advanced in her Natural Subjects, UNSUB and Kith, Curb appropriates public and personal records to critique discrimination against the South Asian community in America’s post-9/11 political landscape. Victor’s poetics enact extreme witnessing, re-establishing the archive’s unheard durations that her modality of the lyric upholds, and recovering locutions of the Indian diaspora eroded or erased by anti-immigrant and anti-Asian racism. Tracing the dynamics of location and locution at the sites of violent events as well as their barely audible frequencies registered in the sequence “Frequency (Alka’s Testimony),” I argue that the archive’s duration in Curb is extended by forms of “sonic agency” (Brandon LaBelle). I further show how, through the poetic work of hearing and sounding (including such techniques as echolocation and ventriloquy), Victor creates a simultaneously critical and lyrical space akin to auditory experience where the text’s multiple durational vectors throw into sharp relief the lives “curbed,” diminished, or destroyed by wounding, fear, and trauma, testifying to the extremity of the very act of witnessing. Finally, focusing on opacity as a fundamental quality of the archive, I also turn to Carolyn Chen’s concrète sound compositions and Amarnath Ravva’s assemblages that traverse Curb, accompanying the poet in collaborative hearing of the archive’s spatial, temporal, and sonic dynamics.

Development of An Audio Frequency Meter with Arduino and MAX4466 Sound Sensor

Sound is one of the areas of study in physics education. Based on the data, it was found that there were difficulties in students' understanding and misconceptions in studying the concept of sound and its parameters. The aim of this research is to design a sound frequency measuring instrument that can visualize one of the parameters in the sound concept: frequency. The research carried out is a type of development research with a 4D model. The results of this research are a series of sound frequency measuring instruments based on Arduino and a Max4466 sound sensor. The validity of the tool was tested with an average validation value of 0.95 in a very good category. The results of calibration using a tuning fork show that the Audio Frequency Meter can consistently measure sound frequencies with an average measurement deviation of 0.514 Hz. Through the results of this research, it is hoped that it can become a reference in developing practical tools for sound concepts.

From noise to sound: Setting the base of packaging sound design for cosmetics by physical, sensory and cognitive characterization of lipstick closing sounds

When envisioning a tube of lipstick, the initial impressions are typically centered around its visual appearance and fragrance. Its sound, specifically the sound of closing the tube, is unlikely to be the first perception to be spontaneously imagined. Even so, consciously or not, a beauty experience is multisensorial, and the overall perception is a weighted combination of all sensory dimensions. Lipstick closing is defined as a noise as it comes from a side effect of packaging produced by the interaction between the packaging conception and the closing gesture. However, this “noise” can become a sound if it is designed specifically to carry functional or emotional cues. This study aims to support sound design for packaging in cosmetics. It consists of a combination of three approaches to better understand the mental categories associated with lipstick closing sounds. Through this combined approach of 1) a Sequential Agglomerative Sorting task with consumers, 2) a sensory decoding by a panel and 3) physical analyses of the sounds, this study provides new evidence of how the sound is perceived with an emphasis on cultural similarities and differences. The results show clear perceptual differences between lipstick sounds but no strong cultural difference between France and China. The description of sound by physical and sensorial measurement highlights the key role of sound duration and frequency in sound discrimination. The goal of this work is to influence the design of lipstick and, more globally, product design by introducing the sound dimension as an essential consideration.

The sensitivity of mechanoelectrical transduction response phase to acoustic overstimulation is calcium-dependent

The Mechanoelectrical transduction (MET) channels of the mammalian hair cells are essential for converting sound stimuli into electrical signals that enable hearing. However, the impact of acoustic overstimulation, a leading cause of hearing loss, on the MET channel function remains poorly understood. In this study, I investigated the effect of loud sound-induced temporary threshold shift (TTS) on the transduction response phase across a wide range of sound frequencies and amplitudes. The results demonstrated an increase in the transduction response phase following TTS, indicating altered transduction apparatus function. Further investigations involving the reduction of extracellular calcium, a known consequence of TTS, replicated the observed phase changes. Additionally, reduction of potassium entry confirmed the specific role of calcium in regulating the transduction response phase. These findings provide novel insights into the impact of loud sound exposure on hearing impairment at the transduction apparatus level and highlight the critical role of calcium in modulating sound transduction. Considering that over 1 billion teenagers and young adults globally are at risk of hearing loss due to unsafe music listening habits, these results could significantly enhance awareness about the damaging effects of loud sound exposure.

1 Creating Sensor Systems for Real Time Animal Management

Abstract Sustainable animal production needs to consider all aspects of sustainability: economic, environmental, and social. Important aspects include 1) waste and odor management, greenhouse gas emissions; 2) animal care and well-being, labor needs, worker safety, and satisfaction; 3) careful use of antibiotics, food safety, and foreign animal disease; and 4) all while the producer needs to make the business show a profit. New technological approaches for building management, animal monitoring, and care should be carefully considered to help satisfy these pressures and concerns. Increases in computing power, sensor systems, and modeling techniques lend themselves to technological advancements in animal agriculture. Research has shown promising results for implementing multiple sensor systems. Precision animal management systems use a variety of sensors to capture real-time data on individual animals and new modeling techniques to process the data into valuable information to aid management decisions. However, data streams from different sources can be problematic. This presentation aims to provide an understanding of current and future technologies and the advantages, difficulties, and pitfalls of processing and combining different types of real-time data. Current technologies used in precision animal management systems include sound, images, and radio frequency identification (RFID) systems. Steps to a successful system include 1) evaluating the needs of the producers and the animals, 2) selecting appropriate sensors, and 3) understanding both the value and the limitation of the captured data and the data processing.

Two methods to improve sound transmission loss in the coincidence region

The building acoustics industry has seen little development away from traditional homogeneous materials. With the inevitable densification of housing, the severity of noise pollution within residential living environments is escalating. While the insulation of high-frequency audible sound through walls is often relatively good between 1 to 5kHz, the overall acoustic performance classification of lightweight wall systems often suffers in this region due to the coincidence effect. This effect results from a more efficient coupling between the incident sound waves and the bending waves initiated within the wall panels. We present an investigation into two contrasting methods to improve the coincidence region. These are i) a multi-layer approach, and ii) the introduction of periodic and quasi-periodic geometrical patterns in the distribution of the mass of the panels. These methods are intended to improve the attenuation of the bending waves by altering a panel's effective stiffness and creating band gaps due to back scattering. Diffuse field results were then used to verify computational models of vibroacoustic transmission based on two different approaches. The experimental and modelling results are in good qualitative agreement and indicate that the addition of impedance change features or surface variations sees a band of significantly attenuation within the targeted band indicating an effective method for either removing or shifting the coincidence effect outside of the most important part of the audible frequency region.

Experimental Study of Storing Electrical Energy Generated by an Acoustic Energy Harvester Into a Supercapacitor

<p class="Abstract">Acoustic energy harvester is a device used to convert environmental noise into electrical energy. Many researches on acoustic energy harvesting have been carried out, but most of them have not yet reached the stage of storing the electrical energy produced. This paper presents an experimental study of storing electrical energy generated by an acoustic energy harvester into a supercapacitor. The acoustic energy harvester in this study used a 4-inch woofer loudspeaker as a noise converter into electricity, equipped with a straight cylindrical resonator, a cylindrical housing, and an electric current rectifier unit. The supercapacitor used has a specification of 100F/2.7V. Experiments were carried out by using several variations of the sound frequency with three variations of sound pressure level (SPL) namely 90 dB, 95 dB, and 100 dB, and by measuring the supercapacitor voltage in a charging time of 60 minutes. It was found that the supercapacitor voltage reached 368 mV which was obtained from noise sound with an SPL of 100 dB and a frequency of 54 Hz which gave an initial charging electric current of about 12 mA. In the last five minutes of charging, the increase in supercapacitor voltage was still linear with time at a rate of about 5.2 mV/min. Therefore, the supercapacitor voltage can still significantly increase if the charging continues.</p>

Acoustic Wave Based Forest Fire Extinguisher and Detection Using Machine Learning

Worldwide, forest fires are a serious hazard to people, property, and the environment, needing creative approaches to early detection and prompt control. In order to establish an intelligent forest fire control system, this research introduces a cutting-edge methodology that blends conventional fire detection techniques with machine learning and cutting-edge technology. To find fires in a forest, we use flame sensors. The flame sensor informs a microcontroller when a fire is found. We offer a revolutionary form of fire suppression using Sonic Fire Extinguisher technology, which puts out flames by emitting high-frequency sound waves, as opposed to traditional fire suppression methods that use water or carbon dioxide. This strategy offers a safer and more environmentally friendly fire suppression technique. The technology incorporates machine learning to improve the speed and accuracy of fire detection. A SD card for sound file storage is included with the ARDUINO UNO microcontroller. In addition, the microcontroller is wired up with an amplifier and speaker. The microcontroller uses machine learning techniques to analyses the characteristics of the fire, such as size and intensity, and chooses the best sound wave frequency for suppression when the flame sensor detects a fire. This device can put out fires more effectively than conventional techniques and can adjust to various fire circumstances. The device can tailor the produced sound waves for effective fire suppression by fusing real-time data from the flame sensor with machine learning insights. This novel strategy improves the safety from forest fires while simultaneously minimizing the negative ecological effects of fire management activities. A promising approach to protecting priceless natural resources, people's lives, and property from the destructive impacts of forest fires is the combination of machine learning and Sonic Fire Extinguisher technology. This research Endeavour marks a significant advancement in the practice of finding fires and extinguishment, allowing a more environmentally responsible and sustainable method of managing forest fires.

Characteristics of resonance sound in a circular saw enclosure

Several studies have been conducted to reduce the idling noise of circular saws because the sound level is extremely high and harms the environment. However, conventional noise suppression technology only controls the vibrations of the circular saw itself, whereas idling noise can be generated when the air inside the enclosure is resonant. In this study, the relationship between the rotational speeds of the circular saw blade and the frequencies of the resonance sound when the circular saw blade is running idle in an enclosure was examined. Additionally, the sound pressure modes and frequencies of the air in the enclosure were analyzed using the finite element method of acoustic analysis. The results showed that resonance sound was generated only when the circular saw blade was enclosed. The frequencies of the resonance sound generated by a circular saw blade made of acrylic plastic were the same as those generated by a steel saw blade. The resonance sound was generated regardless of the outer diameter of the circular saw blade. The peak resonant frequencies formed a step-like line during the analysis in which the rotational speed of the saw blade was steadily increased.