Journal articles on the topic 'Reverberation'
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1
Klimesch, Wolfgang. "The functional meaning of reverberations for sensoric and contextual encoding." Behavioral and Brain Sciences 18, no. 4 (December 1995): 636. http://dx.doi.org/10.1017/s0140525x00040279.
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AbstractAmit argues that the local neuronal spike rate that persists (reverberating) in the absence of the eliciting stimulus represents the code of the eliciting stimulus. Based on the general argument that the inferred functional meaning of reverberation depends in part on the type of representational assumptions, reverberations may only be important for the encoding of contextual information.
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Choo, Youngmin, Woojae Seong, and Wooyoung Hong. "Modeling and Analysis of Monostatic Seafloor Reverberation from Bottom Consisting of Two Slopes." Journal of Computational Acoustics 22, no. 02 (April 17, 2014): 1450005. http://dx.doi.org/10.1142/s0218396x14500052.
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An incoherent reverberation from a continental shelf was simulated using a propagation model based on ray theory combined with several scattering strength formulas. The concept of an N × 2D reverberation model is used to consider azimuthal and radial dependent bottom. For verification of the reverberation model, the result is compared to consensus solutions of problem XI in Reverberation Modeling Workshop I (RMW I). Subsequently, the model is applied to one of data-inspired problems in Reverberation Modeling Workshop II (RMW II). Scattering strength formulas based on the Kirchhoff approximation (KA) and small slope approximation (SSA) are adapted to be applicable to a von Karman roughness spectral form. The monostatic reverberations on the continental shelf are observed at 200 Hz and 1600 Hz for various scattering cross-sections. The results with SSA scattering cross-section are examined to analyze the features of continental shelf reverberation depending on the sound speed profile and bottom slope, and they are found to affect both the pattern and level of reverberations.
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Wang, Zhen, Hao Zhang, Xiao Chen, and Yuan An. "A construction method of reverberation suppression filter using an end-to-end network." PLOS ONE 18, no. 10 (October 24, 2023): e0293365. http://dx.doi.org/10.1371/journal.pone.0293365.
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Reverberation is the primary background interference of active sonar systems in shallow water environments, affecting target position detection accuracy. Reverberation suppression is a signal processing technique used to improve the clarity and accuracy of echo by eliminating the echoes, reverberations, and noise that occur during underwater propagation.This paper proposes an end-to-end network structure called the Reverberation Suppression Network (RS-U-Net) to suppress the reverberation of underwater echo signals. The proposed method effectively improves the signal-to-reverberation ratio (SRR) of the echo signal, outperforming existing methods in the literature. The RS-U-Net architecture uses sonar echo signal data as input, and a one-dimensional convolutional network (1D-CNN) is used in the network to train and extract signal features to learn the main features. The algorithm’s effectiveness is verified by the pool experiment echo data, which shows that the filter can improve the detection of echo signals by about 10 dB. The weights of reverberation suppression tasks are initialized with an auto-encoder, which effectively uses the training time and improves performance. By comparing with the experimental pool data, it is found that the proposed method can improve the reverberation suppression by about 2 dB compared with other excellent methods.
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Sun, Tongjing, Yabin Wen, Xuegang Zhang, Bing Jia, and Mengwei Zhou. "Gaussian Mixture Model for Marine Reverberations." Applied Sciences 13, no. 21 (November 6, 2023): 12063. http://dx.doi.org/10.3390/app132112063.
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Ocean reverberations, a significant interference source in active sonar, arise as a response generated by random scattering at the receiving end, a consequence of randomly distributed clutter or irregular interfaces. Statistical analysis of reverberation data has revealed a predominant adherence to the Rayleigh distribution, signifying its departure from specific distribution forms like the Gaussian distribution. This study introduces the Gaussian mixture model, capable of simulating random variables conforming to a wide array of distributions through the integration of an adequate number of components. Leveraging the unique statistical attributes of reverberation, we initiate the Gaussian mixture model’s parameters via the frequency histogram of the reverberation data. Subsequently, model parameters are estimated using the expectation–maximization (EM) algorithm and the most suitable statistical model is selected based on robust model selection criteria. Through a comprehensive evaluation that encompasses both simulated and observed data, our results underscore the Gaussian mixture model’s effectiveness in accurately characterizing the distribution of reverberation data, yielding a mean squared error of less than 4‰.
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Pang, Jie, and Bo Gao. "Application of a Randomized Algorithm for Extracting a Shallow Low-Rank Structure in Low-Frequency Reverberation." Remote Sensing 15, no. 14 (July 21, 2023): 3648. http://dx.doi.org/10.3390/rs15143648.
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The detection performance of active sonar is often hindered by the presence of seabed reverberation in shallow water. Separating the reverberations from the target echo and noise in the received signal is a crucial challenge in the field of underwater acoustic signal processing. To address this issue, an improved Go-SOR decomposition method is proposed based on the subspace-orbit-randomized singular value decomposition (SOR-SVD). This method successfully extracts the low-rank structure with a certain striation pattern. The results demonstrate that the proposed algorithm outperforms both the original Go algorithm and the current state-of-the-art (SOTA) algorithm in terms of the definition index of the low-rank structure and computational efficiency. Based on the monostatic reverberation theory of the normal mode, it is established that the low-rank structure is consistent with the low-frequency reverberation interference striation. This study examines the interference characteristics of the low-rank structure in the experimental sea area and suggests that the interferences of the fifth and seventh modes mainly control the low-rank structure. The findings of this study can be applied to seafloor exploration, reverberation waveguide invariant (RWI) extraction, and data-driven reverberation suppression methods.
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Naylor, Patrick A., Nikolay D. Gaubitch, and Emanuël A. P. Habets. "Signal-Based Performance Evaluation of Dereverberation Algorithms." Journal of Electrical and Computer Engineering 2010 (2010): 1–5. http://dx.doi.org/10.1155/2010/127513.
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We address the measurement of reverberation in terms of the (DRR) in the context of the assessment of dereverberation algorithms for which we wish to quantify the level of reverberation before and after processing. The DRR is normally calculated from the impulse response of the reverberating system. However, several important dereverberation algorithms involve nonlinear and/or time-varying processing and therefore their effect cannot conveniently be represented in terms of modifications to the impulse response of the reverberating system. In such cases, we show that a good estimate of DRR can be obtained from the input/output signals alone using the Signal-to-Reverberant Ratio (SRR) only if the source signal is spectrally white and correctly normalized. We study alternative normalization schemes and conclude by showing a least squares optimal normalization procedure for estimating DRR using signal-based SRR measurement. Simulation results illustrate the accuracy of DRR estimation using SRR.
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Hung, Alex Ling Yu, Edward Chen, and John Galeotti. "Weakly- and Semisupervised Probabilistic Segmentation and Quantification of Reverberation Artifacts." BME Frontiers 2022 (March 1, 2022): 1–15. http://dx.doi.org/10.34133/2022/9837076.
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Objective and Impact Statement. We propose a weakly- and semisupervised, probabilistic needle-and-reverberation-artifact segmentation algorithm to separate the desired tissue-based pixel values from the superimposed artifacts. Our method models the intensity decay of artifact intensities and is designed to minimize the human labeling error. Introduction. Ultrasound image quality has continually been improving. However, when needles or other metallic objects are operating inside the tissue, the resulting reverberation artifacts can severely corrupt the surrounding image quality. Such effects are challenging for existing computer vision algorithms for medical image analysis. Needle reverberation artifacts can be hard to identify at times and affect various pixel values to different degrees. The boundaries of such artifacts are ambiguous, leading to disagreement among human experts labeling the artifacts. Methods. Our learning-based framework consists of three parts. The first part is a probabilistic segmentation network to generate the soft labels based on the human labels. These soft labels are input into the second part which is the transform function, where the training labels for the third part are generated. The third part outputs the final masks which quantifies the reverberation artifacts. Results. We demonstrate the applicability of the approach and compare it against other segmentation algorithms. Our method is capable of both differentiating between the reverberations from artifact-free patches and modeling the intensity fall-off in the artifacts. Conclusion. Our method matches state-of-the-art artifact segmentation performance and sets a new standard in estimating the per-pixel contributions of artifact vs underlying anatomy, especially in the immediately adjacent regions between reverberation lines. Our algorithm is also able to improve the performance of downstream image analysis algorithms.
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Hu, Ning, Xin Rao, Jiabao Zhao, Shengjie Wu, Maofa Wang, Yangzhen Wang, Baochun Qiu, Zhenjing Zhu, Zitong Chen, and Tong Liu. "A Shallow Seafloor Reverberation Simulation Method Based on Generative Adversarial Networks." Applied Sciences 13, no. 1 (January 1, 2023): 595. http://dx.doi.org/10.3390/app13010595.
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Reverberation characteristics must be considered in the design of sonar. The research on reverberation characteristics is based on a large number of actual reverberation data. Due to the cost of trials, it is not easy to obtain actual lake and sea trial reverberation data, which leads to a lack of actual reverberation data. Traditionally, reverberation data are obtained by modeling the generation mechanism of seafloor reverberation. The usability of the models requires a large amount of actual seafloor reverberation data to verify. In terms of the reverberation modeling theory, scattering models are mostly empirical, computationally intensive and inefficient. In order to solve the above obstacles, we propose a shallow seafloor reverberation data simulation method based on the generative adversarial network (GAN), which uses a small amount of actual reverberation data as reference samples to train the GAN to generate more reverberation data. The reverberation data generated by the GAN are compared with that simulated by traditional methods, and it is found that the reverberation data generated by the GAN meet the reverberation characteristics. Once the network is trained, the reverberation data are generated with very little computation. In addition, the method is universal and can be applied to any sea area. Compared with the traditional method, this method has a simple modeling idea, less computation and strong universality. It can be used as an alternative method for sea trials to provide data support for the study of seafloor reverberation characteristics, and it has broad application prospects in antireverberation technology research and active sonar design.
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WU, J. R., E. C. SHANG, and T. F. GAO. "A NEW ENERGY-FLUX MODEL OF WAVEGUIDE REVERBERATION BASED ON PERTURBATION THEORY." Journal of Computational Acoustics 18, no. 03 (September 2010): 209–25. http://dx.doi.org/10.1142/s0218396x10004152.
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The modal shallow water reverberation theory and the energy-flux shallow water reverberation theory were combined to get a new energy-flux model of waveguide reverberation based on Perturbation theory. There are only three environmental parameters (P, Q, μ) in the new reverberation model. It has clear physical picture and it is satisfied the waveguide constraint without any adjustable parameters. The new energy-flux reverberation model was compared with the modal reverberation model (full-wave reverberation model). The results show that the new model can explain the shallow water reverberation in most cases. It is shown that the contributions of parameter P and Q are mutual compensated (coupled) for a fixed reverberation data, therefore it is hard to extract both of them simultaneously. Finally, parameters P and μ at different frequencies were extracted from the reverberation data of "Qingdao-2005 experiment" in Yellow sea shallow-water area where the parameter Q has been extracted from mode filtering approach previously.
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Kyong, Jeong-Sug, Chanbeom Kwak, Woojae Han, Myung-Whan Suh, and Jinsook Kim. "Effect of Speech Degradation and Listening Effort in Reverberating and Noisy Environments Given N400 Responses." Journal of Audiology and Otology 24, no. 3 (July 10, 2020): 119–26. http://dx.doi.org/10.7874/jao.2019.00514.
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Background and Objectives: In distracting listening conditions, individuals need to pay extra attention to selectively listen to the target sounds. To investigate the amount of listening effort required in reverberating and noisy backgrounds, a semantic mismatch was examined.Subjects and Methods: Electroencephalography was performed in 18 voluntary healthy participants using a 64-channel system to obtain N400 latencies. They were asked to listen to sounds and see letters in 2 reverberated×2 noisy paradigms (i.e., Q-0 ms, Q-2000 ms, 3 dB-0 ms, and 3 dB-2000 ms). With auditory-visual pairings, the participants were required to answer whether the auditory primes and letter targets did or did not match. Results: Q-0 ms revealed the shortest N400 latency, whereas the latency was significantly increased at 3 dB-2000 ms. Further, Q-2000 ms showed approximately a 47 ms delayed latency compared to 3 dB-0 ms. Interestingly, the presence of reverberation significantly increased N400 latencies. Under the distracting conditions, both noise and reverberation involved stronger frontal activation. Conclusions: The current distracting listening conditions could interrupt the semantic mismatch processing in the brain. The presence of reverberation, specifically a 2000 ms delay, necessitates additional mental effort, as evidenced in the delayed N400 latency and the involvement of the frontal sources in this study.
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Volman, Vladislav, and Richard C. Gerkin. "Synaptic Scaling Stabilizes Persistent Activity Driven by Asynchronous Neurotransmitter Release." Neural Computation 23, no. 4 (April 2011): 927–57. http://dx.doi.org/10.1162/neco_a_00098.
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Small networks of cultured hippocampal neurons respond to transient stimulation with rhythmic network activity (reverberation) that persists for several seconds, constituting an in vitro model of synchrony, working memory, and seizure. This mode of activity has been shown theoretically and experimentally to depend on asynchronous neurotransmitter release (an essential feature of the developing hippocampus) and is supported by a variety of developing neuronal networks despite variability in the size of populations (10–200 neurons) and in patterns of synaptic connectivity. It has previously been reported in computational models that “small-world” connection topology is ideal for the propagation of similar modes of network activity, although this has been shown only for neurons utilizing synchronous (phasic) synaptic transmission. We investigated how topological constraints on synaptic connectivity could shape the stability of reverberations in small networks that also use asynchronous synaptic transmission. We found that reverberation duration in such networks was resistant to changes in topology and scaled poorly with network size. However, normalization of synaptic drive, by reducing the variance of synaptic input across neurons, stabilized reverberation in such networks. Our results thus suggest that the stability of both normal and pathological states in developing networks might be shaped by variance-normalizing constraints on synaptic drive. We offer an experimental prediction for the consequences of such regulation on the behavior of small networks.
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Takeda, Ryu, Kazuhiro Nakadai, Toru Takahashi, Kazunori Komatani, Tetsuya Ogata, and Hiroshi G. Okuno. "Efficient Blind Dereverberation and Echo Cancellation Based on Independent Component Analysis for Actual Acoustic Signals." Neural Computation 24, no. 1 (January 2012): 234–72. http://dx.doi.org/10.1162/neco_a_00219.
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This letter presents a new algorithm for blind dereverberation and echo cancellation based on independent component analysis (ICA) for actual acoustic signals. We focus on frequency domain ICA (FD-ICA) because its computational cost and speed of learning convergence are sufficiently reasonable for practical applications such as hands-free speech recognition. In applying conventional FD-ICA as a preprocessing of automatic speech recognition in noisy environments, one of the most critical problems is how to cope with reverberations. To extract a clean signal from the reverberant observation, we model the separation process in the short-time Fourier transform domain and apply the multiple input/output inverse-filtering theorem (MINT) to the FD-ICA separation model. A naive implementation of this method is computationally expensive, because its time complexity is the second order of reverberation time. Therefore, the main issue in dereverberation is to reduce the high computational cost of ICA. In this letter, we reduce the computational complexity to the linear order of the reverberation time by using two techniques: (1) a separation model based on the independence of delayed observed signals with MINT and (2) spatial sphering for preprocessing. Experiments show that the computational cost grows in proportion to the linear order of the reverberation time and that our method improves the word correctness of automatic speech recognition by 10 to 20 points in a RT20= 670 ms reverberant environment.
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Faris, Wendy B. "The Onset of the Image in Individual and Historical Consciousness: Visionary Moments in the Texts of Carlos Fuentes." PMLA/Publications of the Modern Language Association of America 128, no. 3 (May 2013): 701–4. http://dx.doi.org/10.1632/s0030812900122977.
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Gaston Bachelard, justifying his phenomenological method, emphasizes “the onset of the image in an individual consciousness,” provocatively states that “the poetic act has no past,” and asserts that “the image, in its simplicity, has no need of scholarship” (xv, xi, xv). Bachelard hedges his bets, qualifying the statement about the poetic act's having “no past” with “at least no recent past” (xi). And soon, admitting that while for him the image's primary effect “involves bringing about a veritable awakening of poetic creation, even in the soul of the reader, through the reverberations of a single poetic image,” a reverberation through which, “by going immediately beyond all psychology or psychoanalysis, we feel a poetic power rising naively within us,” nevertheless, “after the original reverberation, we are able to experience resonances, sentimental repercussions, reminders of our past.” But, he hastens to add, “the image has touched the depths before it stirs the surface” (xix).
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Kou, Siwei, Xi'an Feng, Hui Huang, and Yang Bi. "A Space-Time Adaptive Processing Method Based on Sparse Reconstruction of Reverberation Interference." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 38, no. 6 (December 2020): 1179–87. http://dx.doi.org/10.1051/jnwpu/20203861179.
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Aiming at the problem of how to obtain reverberation samples and estimate their covariance matrix in the space-time adaptive processing(STAP) of sonar system, a new space-time adaptive processing method is proposed based on sparse reconstruction of reverberation in this paper. Firstly, according to the space-time distribution characteristics of reverberation received by moving platform sonar, a space-time steering dictionary for sparse reconstruction of reverberation is designed along the relation curve between Doppler frequency shift and incident cone angle cosine of the reverberation unit. Then, a reverberation sample in the rangecell under test (RUT) is reconstructed with high precision by sparse decomposition of signals obtained from the sonar array in the space-time steering dictionary. Finally, based on the prior information of reverberation probability distribution model, a sufficient number of reverberation samples are generated to meet the requirement of performance loss index on reverberation sample size in the space-time adaptive processing, so as to correctly obtain estimation of the covariance matrix of reverberation. This method can reconstruct the reverberation samples and estimate the reverberation covariance matrix directly from the data in RUT without relying on the auxiliary data from units adjacent to the RUT. Therefore, it is not only suitable for the environment with constant reverberation statistical characteristics, but also suitable for the environment with varying statistical characteristics. Simulation results of sonar forward-looking array and side-looking array indicate that the improvement factor of the proposed method is about 10dB lower than the traditional space-time adaptive processing method. So this new STAP method has good anti-reverberation performance.
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Koriakin, Olexii. "METHODS OF USING ARTIFICIAL REVERBERATION IN MODERN SOUND ENGINEERING." OPEN EDUCATIONAL E-ENVIRONMENT OF MODERN UNIVERSITY, no. 12 (2022): 49–58. http://dx.doi.org/10.28925/2414-0325.2022.124.
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The article is devoted to the systematization of the main modern methods of using reverberation in sound engineering and methodological bases of its use in the educational process in higher education institutions. Scientific novelty is to clarify the classification and systematization of the main modern methods of using artificial reverberation, as well as methodological principles of mastering artificial reverberation in the process of training. The purpose of the article is to systematize the main modern methods of using reverberation in sound engineering. To achieve this goal, the following methods were used: system-analytical, art history and comparative-historical. The main results and conclusions of the research. The evolution of digital technologies in the field of sound engineering, the introduction of reverberation algorithms have greatly contributed to the expansion of the use of artificial reverberation in sound engineering. The article briefly describes "convolutional" reverberation as one that operates with the most modern reverberation algorithm. Currently, a variety of effective methods of artificial reverberation using has been developed in sound engineering, which can be used to implement various creative tasks. The article describes the methods of using artificial reverberation for sound perspective creating; for back-vocal processing; for delay processing; for "softening" the sound of individual parts of musical instruments; for different signals of the same type processing; for solo batch processing using two reverb effects. Some types of artificial reverberation were used at different stages of the music industry development. The current state of software development allows the use of several reverb algorithms simultaneously, making it possible to create original sounds. In the process of mastering of various methods of using artificial reverberation by higher education students, it is best to start their acquaintance with artificial reverberation from the simplest reverberation effects, which can be implemented in "analog" effects processor, in which only some parameters vary based on the manufacturer's algorithms. Further mastering of artificial reverberation should be carried out through software (in particular, free VST-plugins of artificial reverberation) used in digital audio workstations (DAW).
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Harada, Yuna, Yuting Geng, Kenta Iwai, Masato Nakayama, and Takanobu Nishiura. "Subjective evaluation for sharp sound image construction based on reverberation control with surround sound system using parametric and electro-dynamic loudspeakers." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 265, no. 4 (February 1, 2023): 3464–71. http://dx.doi.org/10.3397/in_2022_0493.
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3-D sound field reproduction systems can provide a high presence. These systems commonly use electro-dynamic loudspeakers. Electro-dynamic loudspeakers tend to construct diffuse sound images due to its wide directivity and high reverberation. In contrast, parametric array loudspeakers can construct sharp sound images due to its sharp directivity and low reverberation. On the other hand, it is difficult to provide reverberation presence by parametric array loudspeakers because of the sharp directivity. We have previously proposed a sharp sound image construction based on reverberation control with surround sound system using parametric and electro-dynamic loudspeakers. In this method, the sharp sound image is rendered using parametric array loudspeakers, and the reverberation presence is provided by electro-dynamic loudspeakers, emitting reverberation signals synthesized with reverberation control filters. Through the objective experiments, we have confirmed that this method can construct the sharp sound image with reverberation presence. In this paper, we conduct subjective experiments to confirm if the listeners can perceive the reverberation presence provided by the proposed method. In particular, we evaluated the sharpness and direction of the sound image, and the reverberation presence with objective and subjective evaluation experiments. From the subjective evaluation, we confirmed that the reverberation presence can be perceived.
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Lee, Sang-Kwon, and Dong-June Yu. "Measurement of reverberation time of a passenger car utilizing the wavelet filter bank." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 219, no. 3 (March 1, 2005): 329–36. http://dx.doi.org/10.1243/095440705x6686.
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A few researchers have tried to find the measurement of the reverberation time of a passenger car. However, this has proved to be extremely difficult because the reverberation time of a passenger car is too short to measure using the traditional bandpass filter. If the reverberation time is very short, the product of the reverberation time ( T) and the bandwidth ( B) of the traditional bandpass filter is very small. The low level of the product BT required for the measurement of the reverberation time using the traditional bandpass filter is 16. In order to overcome this problem, the wavelet filter bank has been developed. In the paper, this new wavelet filter is employed to measure the reverberation times of five different classes of passenger car. The low level of the product BT required for the measurement of reverberation time using the wavelet filter is 4. Therefore, it was possible to measure the reverberation times of five passenger cars successfully using the new wavelet filter bank. It is found that the reverberation times measured in most passenger cars are around 0.04. It is a very short reverberation time compared with those of general acoustic rooms like a concert hall.
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Edelman, Shimon. "How representation works is more important than what representations are." Behavioral and Brain Sciences 18, no. 4 (December 1995): 630–31. http://dx.doi.org/10.1017/s0140525x00040218.
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AbstractA theory of representation is incomplete if it states “representations areX” whereXcan be symbols, cell assemblies, functional states, or the flock of birds fromTheaetetus, without explaining the nature of the link between the universe ofXs and the world. Amit's thesis, equating representations with reverberations in Hebbian cell assemblies, will only be considered a solution to the problem of representation when it is complemented by a theory of how a reverberation in the brain can be a representation of anything.
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Yang, T. C. "Reverberation imaging." Journal of the Acoustical Society of America 91, no. 4 (April 1992): 2344. http://dx.doi.org/10.1121/1.403461.
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Shinoda, Ryuichi. "Reverberation circuit." Journal of the Acoustical Society of America 91, no. 4 (April 1992): 2304. http://dx.doi.org/10.1121/1.403624.
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Ellis, Dale R., John R. Preston, Heinz G. Urban, and Robert J. Urick. "Ocean Reverberation." Journal of the Acoustical Society of America 96, no. 4 (October 1994): 2616. http://dx.doi.org/10.1121/1.411315.
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Shibata, Takashi, and Masaaki Nishimura. "Reverberation apparatus." Journal of the Acoustical Society of America 77, no. 1 (January 1985): 339. http://dx.doi.org/10.1121/1.391886.
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Mi, Huan, Gavin Kearney, and Helena Daffern. "Perceptual Similarities between Artificial Reverberation Algorithms and Real Reverberation." Applied Sciences 13, no. 2 (January 7, 2023): 840. http://dx.doi.org/10.3390/app13020840.
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This paper presents a study evaluating the perceptual similarity between artificial reverberation algorithms and acoustic measurements. An online headphone-based listening test was conducted and data were collected from 20 expert assessors. Seven reverberation algorithms were tested in the listening test, including the Dattorro, Directional Feedback Delay Network (DFDN), Feedback Delay Network (FDN), Gardner, Moorer, and Schroeder reverberation algorithms. A new Hybrid Moorer–Schroeder (HMS) reverberation algorithm was included as well. A solo cello piece, male speech, female singing, and a drumbeat were rendered with the seven reverberation algorithms in three different reverberation times (0.266 s, 0.95 s and 2.34 s) as the test conditions. The test was conducted online and based on the Multiple Stimuli with Hidden Reference and Anchor (MUSHRA) paradigm. The reference conditions consisted of the same audio samples convolved with measured binaural room impulse responses (BRIRs) with the same three reverberation times. The anchor was dual-mono 3.5 kHz low pass filtered audio. The similarity between the test audio and the reference audio was scored on a scale of zero to a hundred. Statistical analysis of the results shows that the Gardner and HMS reverberation algorithms are good candidates for exploration of artificial reverberation in Augmented Reality (AR) scenarios in future research.
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Harada, Yuna, Kenta Iwai, Masato Nakayama, and Takanobu Nishiura. "3-D sound field reproduction with reverberation control on surround sound system by combining parametric and electro-dynamic loudspeakers." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, no. 5 (August 1, 2021): 1083–94. http://dx.doi.org/10.3397/in-2021-1751.
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Recently, with the development of video technology, 3-D sound field reproduction systems that can provide a high presence have attracted attention. Conventional systems with electro-dynamic loudspeakers have a problem that the sound image lacks sharpness when constructing a narrow sound image. To solve this problem, we utilize a parametric array loudspeaker which has sharp directivity by the straightness of ultrasounds. Parametric array loudspeakers can produce sharper sound images due to the sharper directivity and lower reverberation compared with electro-dynamic loudspeakers. However, it is difficult to represent reverberation by parametric array loudspeakers. In this paper, we propose a method for 3-D sound field reproduction to achieve both the sharp images and reverberation presence by combing parametric array loudspeakers and electro-dynamic loudspeakers in surround sound system. In the proposed method, sharp sound images are rendered by parametric array loudspeakers and the reverberation presence is provided by electro-dynamic loudspeakers, emitting reverberation signals synthesized with a reverberation control filter. The reverberation control filter is adaptively designed to reproduce the reverberation time and the direct-to-reverberation ratio of the target sound field in other environments. The experimental results show that the proposed method can achieve the reproducing the sharp sound image with some reverberation presence.
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Chen, Tuo, Qiming Ma, Zheyuan Zhou, and He Lu. "Research on reverberation characteristics analysis and suppression methods for active continuous detection." MATEC Web of Conferences 283 (2019): 07010. http://dx.doi.org/10.1051/matecconf/201928307010.
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Compared with the traditional active detection with monopulse periodic emission mode, active continuous detection has the advantages of large emission duty ratio and continuous acquisition of process information. It can effectively overcome the disadvantages of high false alarm probability, poor environment adaptation ability and low detection efficiency in traditional active detection, so then improving the system detection ability. But active continuous detection is also facing more serious reverberation. In order to further improve capacity, the adaptable reverberation characteristics and detection methods are carried out in this paper. On the basis of theoretical modelling, the relationship between the characteristics of the active continuous detection reverberation and the signal form, the hydrological environment and the emission power are studied. The time frequency characteristics of reverberation and the attenuation law with distance of reverberation are mastered. A reverberation suppression method based on adaptive beamforming of sub-band steered minimum variance algorithm (SSMV) is studied for active continuous detection. Considering signal bandwidth and fast convergence, etc. The relationship between sub-array partition and reverberation suppression ability is analyzed. The validity of reverberation characteristic analysis is verified by simulation, the performance of the method of reverberation suppression is verified by sea trial data processing.
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Bai, Mingsian R., and Kwuen-Yieng Ou. "Synthesis of Room Responses Using the Virtual Source Representation and the Comb-Nested Allpass Filters." Journal of Vibration and Acoustics 128, no. 6 (October 9, 2005): 690–98. http://dx.doi.org/10.1115/1.2360951.
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An artificial reverberator is proposed in this paper to synthesize room responses. The method employs the virtual source representation and the comb-nested allpass filters to generate the early reflection and late reverberation, respectively, of room responses. The virtual source method is based on a simple representation of sound field with a distribution of discrete simple sources on the boundary. The complex strengths of the virtual sources are then calculated by solving a frequency domain least-square problem. Parameters such as room geometry, size, and wall absorption are naturally incorporated into the synthesis process. The filtering property of human hearing is also exploited in a nonuniform sampling procedure to further simplify the computation. Apart from the early reflection, a comb-allpass filter network is adopted to simulate late reverberations. Optimal parameters of the comb-allpass filter network are obtained using the genetic algorithm (GA). The energy decay curve (EDC) is chosen as the objective function in the GA procedure. Numerical simulations are carried out for a rectangular room and a concert hall model to verify the proposed technique. Subjective listening experiments demonstrate that the present technique is capable of conferring remarkable realism of room responses.
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Reinhart, Paul N., and Pamela E. Souza. "Listener Factors Associated with Individual Susceptibility to Reverberation." Journal of the American Academy of Audiology 29, no. 01 (January 2018): 073–82. http://dx.doi.org/10.3766/jaaa.16168.
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AbstractReverberation is a source of acoustic degradation, present to varying extents in many everyday listening environments. The presence of reverberation decreases speech intelligibility, especially for listeners with hearing impairment. There is substantial variability in how susceptible individuals with hearing impairment are to the effects of reverberation (i.e., how intelligible reverberant speech is to a listener). Relatively little is known about the listener factors which drive that susceptibility.To identify listener factors that are associated with an individual’s susceptibility to reverberation. Another purpose was to investigate how these listener factors are associated with reverberant susceptibility in relation to the amount of reverberation. The listener factors investigated were degree of hearing loss, age, temporal envelope sensitivity, and working memory capacity.This study used a correlational design to investigate the association between different listener factors and speech intelligibility with varying amounts of reverberation.Thirty-three older adults with sensorineural hearing loss participated in the study.Listener temporal envelope sensitivity was measured using a gap detection threshold task. Listener working memory capacity was measured using the Reading Span Test. Intelligibility of reverberant speech was measured using a set of low-context sentence materials presented at 70 dB SPL without individual frequency shaping. Sentences were presented at a range of realistic reverberation times, including no reverberation (0.0 sec), moderate reverberation (1.0 sec), and severe reverberation (4.0 sec). Stepwise linear regression analyses were conducted to model speech intelligibility using individual degree of hearing loss, age, temporal envelope sensitivity, and working memory capacity. A separate stepwise linear regression model was conducted to model listener speech intelligibility at each of the three levels of reverberation.As the amount of reverberation increased, listener speech intelligibility decreased and variability in scores among individuals increased. Temporal envelope sensitivity was most closely associated with speech intelligibility in the no reverberation condition. Both listener age and degree of hearing loss were significantly associated with speech intelligibility in the moderate reverberation condition. Both listener working memory capacity and age were significantly associated with speech intelligibility in the severe reverberation condition.The results suggest that suprathreshold listener factors can be used to best predict speech intelligibility across a range of reverberant conditions. However, which listener factor(s) to consider when predicting a listener’s susceptibility to reverberation depends on the amount of reverberation in an environment. Clinicians may be able to use different listener factors to identify individuals who are more susceptible to reverberation and would be more likely to have difficulty communicating in reverberant environments.
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Tong, Feng, Wei He, Jiayang Zhang, and Yuanxun Kang. "Deep-learning driven reverberation-aware microphone array speech enhancement." Journal of the Acoustical Society of America 154, no. 4_supplement (October 1, 2023): A99. http://dx.doi.org/10.1121/10.0022921.
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Traditional microphone array speech enhancement algorithms suffer from significant performance degradation in complex and diverse speech application scenarios. The adoption of data-driven microphone array optimization models based on machine learning (deep learning) is capable of achieve significant performance improvements. However, such methods exhibit data dependency. A deep learning based reverberation-aware microphone array speech enhancement algorithm is proposed. The proposed algorithm first obtains the reverberation pattern through reverberation-aware environment probing, and then extracts the main component features to train reverberation-aware network (RAN). This operation enables the RAN to have the ability to decouple and generate adaptive de-reverberation beamforming coefficients based on reverberation features. Simulation and experiments are provided to verify the effectiveness and robustness of the proposed method in different reverbrant environments.
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Li, Yan-Rong, and Jian-Min Wang. "Spectroastrometric Reverberation Mapping of Broad-line Regions." Astrophysical Journal 943, no. 1 (January 1, 2023): 36. http://dx.doi.org/10.3847/1538-4357/aca66d.
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Abstract Spectroastrometry measures source astrometry as a function of wavelength/velocity. Reverberations of spectroastrometric signals naturally arise in broad-line regions (BLRs) of active galactic nuclei (AGNs) as a result of the continuum variations that drive responses of the broad emission lines with time delays. Such signals provide a new diagnostic for mapping BLR kinematics and geometry, complementary to the traditional intensity reverberation mapping (RM) technique. We present a generic mathematical formalism for spectroastrometric RM and show that under realistic parameters of a phenomenological BLR model, the spectroastrometric reverberation signals vary on a level of several to tens of microarcseconds, depending on the BLR size, continuum variability, and angular-size distance. We also derive the analytical expressions of spectroastrometric RM for an inclined ring-like BLR. We develop a Bayesian framework with a sophisticated Monte Carlo sampling technique to analyze spectroastrometric data and infer the BLR properties, including the central black hole mass and angular-size distance. We demonstrate the potential of spectroastrometric RM in spatially resolving BLR kinematics and geometry through a suite of simulation tests. The application to realistic observation data of 3C 273 obtains tentative, but enlightening results, reinforcing the practical feasibility of conducting spectroastrometric RM experiments on bright AGNs with the operating Very Large Telescope Interferometer as well as possibly with the planned next-generation 30 m class telescopes.
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Nowoświat, Artur. "Impact of Temperature and Relative Humidity on Reverberation Time in a Reverberation Room." Buildings 12, no. 8 (August 21, 2022): 1282. http://dx.doi.org/10.3390/buildings12081282.
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Changes in acoustic parameters measured in a room may depend on the location and orientation of the sound source and microphones or on the reverberation conditions of the room. As was found in the research presented in this publication, reverberation in a room is also influenced by thermo-hygrometric conditions. The article presents an experimental analysis involving the impact of temperature and relative air humidity in a room on reverberation time. Since it is very difficult to control the temperature and relative humidity in real conditions, the tests were carried out both in laboratory conditions and with the use of simulations. For this purpose, the results of the reverberation time measurements in the reverberation chamber for various thermo-hygrometric conditions were obtained. Then, the reverberation chamber was modeled in the ODEON Version 11.0 program, and after the validation of the model, a series of simulations were performed, demonstrating the changes in the reverberation time as a function of temperature and relative air humidity. The results are presented in both a two-dimensional and three-dimensional version, i.e., the dependence of the reverberation time as a function of two variables: air temperature and relative humidity.
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Kolarik, Andrew J., Brian C. J. Moore, Silvia Cirstea, Elena Aggius-Vella, Monica Gori, Claudio Campus, and Shahina Pardhan. "Factors Affecting Auditory Estimates of Virtual Room Size: Effects of Stimulus, Level, and Reverberation." Perception 50, no. 7 (May 30, 2021): 646–63. http://dx.doi.org/10.1177/03010066211020598.
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When vision is unavailable, auditory level and reverberation cues provide important spatial information regarding the environment, such as the size of a room. We investigated how room-size estimates were affected by stimulus type, level, and reverberation. In Experiment 1, 15 blindfolded participants estimated room size after performing a distance bisection task in virtual rooms that were either anechoic (with level cues only) or reverberant (with level and reverberation cues) with a relatively short reverberation time of T60 = 400 milliseconds. Speech, noise, or clicks were presented at distances between 1.9 and 7.1 m. The reverberant room was judged to be significantly larger than the anechoic room ( p < .05) for all stimuli. In Experiment 2, only the reverberant room was used and the overall level of all sounds was equalized, so only reverberation cues were available. Ten blindfolded participants took part. Room-size estimates were significantly larger for speech than for clicks or noise. The results show that when level and reverberation cues are present, reverberation increases judged room size. Even relatively weak reverberation cues provide room-size information, which could potentially be used by blind or visually impaired individuals encountering novel rooms.
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Nowoświat, Artur. "Determination of the Reverberation Time Using the Measurement of Sound Decay Curves." Applied Sciences 13, no. 15 (July 26, 2023): 8607. http://dx.doi.org/10.3390/app13158607.
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In the measurements of reverberation time, measurement methods of different accuracy are used depending on the room. For ordinary rooms, the measurements are made using the interrupted noise method, which consists of determining the decay curve after switching off the excitation source of the room. The measurements are made for different source arrangements and different receiver arrangements, and at least three repetitions are made at each of such points. Due to such a realization of measurements, several dozen different reverberation curves are obtained, from which the reverberation time is read out. This article demonstrates the differences between reverberation time readouts, depending on the averaging method of reverberation curves. The first analyzed method is based on reading out the reverberation times for each obtained curve and on averaging the results obtained in this way. The second analyzed method involves averaging the reverberation curves using the linear regression method and then determining a simple regression on the basis of which the reverberation time is read out. For each method, different average reverberation time values and different standard uncertainties were obtained. The difference for the 500 Hz frequency band in a teaching room for the measurement uncertainty is 0.28 s. The results obtained in the article are extremely important when designing interiors intended for the reception of verbal sound, in particular teaching rooms.
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Oh. "Low-Frequency Normal Mode Reverberation Model." Journal of the Acoustical Society of Korea 34, no. 3 (2015): 184. http://dx.doi.org/10.7776/ask.2015.34.3.184.
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Wang, Jingyi, Erin Kara, Matteo Lucchini, Adam Ingram, Michiel van der Klis, Guglielmo Mastroserio, Javier A. García, et al. "The NICER “Reverberation Machine”: A Systematic Study of Time Lags in Black Hole X-Ray Binaries." Astrophysical Journal 930, no. 1 (May 1, 2022): 18. http://dx.doi.org/10.3847/1538-4357/ac6262.
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Abstract We perform the first systematic search of all NICER archival observations of black hole (and candidate) low-mass X-ray binaries for signatures of reverberation. Reverberation lags result from the light travel time difference between the direct coronal emission and the reflected disk component, and therefore their properties are a useful probe of the disk-corona geometry. We detect new signatures of reverberation lags in eight sources, increasing the total sample from three to 11, and study the evolution of reverberation lag properties as the sources evolve in outbursts. We find that in all of the nine sources with more than one reverberation lag detection, the reverberation lags become longer and dominate at lower Fourier frequencies during the hard-to-soft state transition. This result shows that the evolution in reverberation lags is a global property of the state transitions of black hole low-mass X-ray binaries, which is valuable in constraining models of such state transitions. The reverberation lag evolution suggests that the corona is the base of a jet that vertically expands and/or gets ejected during state transition. We also discover that in the hard state, the reverberation lags get shorter, just as the quasiperiodic oscillations (QPOs) move to higher frequencies, but then in the state transition, while the QPOs continue to higher frequencies, the lags get longer. We discuss the implications of the coronal geometry and physical models of QPOs in light of this new finding.
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Yang, Shiuh-Kuang, Shih-Ming Chiu, and Ruey-Chang Wei. "Study of reverberation pattern and its cancellation method in shallow water." Theoretical and Applied Mechanics 34, no. 3 (2007): 173–95. http://dx.doi.org/10.2298/tam0703173y.
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In shallow water, the primary limitation of the performance of active sonar is the reverberation that originates from volume and boundaries scattering as well as multi-path propagation. There?fore, reverberation cancelation is an important research topic for increasing the performance of active sonar in shallow water. In this research, the reverberation pattern is simulated using MAT?LAB software. The simulated frequency is 30-kHz in the research. There are two main aims of this work. The first is to create the signals that include the reverberation and the target. The second is to perform the reverberation cancelation for the active sonar in shallow water. The analysis of the reverberation for the spherical target is based on the propagation theory of image source, surface scattering of Rayleigh criterion of roughness, bottom scattering of Lambert?s Law, and multiple scattering. The signal containing the reverberation and the target is then compressed or enhanced by AGC (Automatic Gain Control). The echo of the target is then distinguished through the method of cross correlation. The follow?ing phenomena can be found: (a) AGC can compress the signal in a speci?c dynamic range. (b) cross correlation can be used to locate and distinguish the echoes of the target in a high reverberation environment.
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Wang, Yueyue, Xianhui Li, Junjuan Zhao, Xingyun Li, Liying Zhu, and Wenjiang Wang. "Influence of the acoustic structures placement on the measurements in a reverberation room." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, no. 6 (August 1, 2021): 429–33. http://dx.doi.org/10.3397/in-2021-1474.
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Absorption coefficient is a signification index of acoustic structures, which is useful to determine acoustic treatment with a good sound-absorbing characteristic. To make the sound absorption of acoustic structures measured in a reverberation room more closely approximates the sound absorption that would be performed under the applicational condition, this paper studies the influence of different placements on the measurements in the reverberation room. In this paper, the absorption coefficients of micro-perforated membrane and micro-perforated stretch ceiling space sound absorbers are measured, which are placing in the middle of the reverberation room, close to the side walls of the reverberation room and in the corner of the reverberation room respectively. The experiments show that different placements of acoustic material in reverberation room have obvious effect on sound absorption above the 500Hz. It is more efficient to place materials in the middle of the reverberation room, while the absorption of being close to the side walls or in the corner of the reverberation room weakens. The results were agreed with the measurement of micro-perforated stretch ceiling space sound absorbers. It is useful to optimize the arrangement of acoustic materials and structures in controlling the building and rooms noise.
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Arau-Puchades, Higini, and Umberto Berardi. "A Revised Sound Energy Theory Based on a New Formula for the Reverberation Radius in Rooms with Non-Diffuse Sound Field." Archives of Acoustics 40, no. 1 (March 1, 2015): 33–40. http://dx.doi.org/10.1515/aoa-2015-0005.
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Abstract This paper discusses the concept of the reverberation radius, also known as critical distance, in rooms with non-uniformly distributed sound absorption. The reverberation radius is the distance from a sound source at which the direct sound level equals the reflected sound level. The currently used formulas to calculate the reverberation radius have been derived by the classic theories of Sabine or Eyring. However, these theories are only valid in perfectly diffused sound fields; thus, only when the energy density is constant throughout a room. Nevertheless, the generally used formulas for the reverberation radius have been used in any circumstance. Starting from theories for determining the reverberation time in non- diffuse sound fields, this paper firstly proposes a new formula to calculate the reverberation radius in rooms with non-uniformly distributed sound absorption. Then, a comparison between the classic formulas and the new one is performed in some rectangular rooms with non-uniformly distributed sound absorption. Finally, this paper introduces a new interpretation of the reverberation radius in non-diffuse sound fields. According to this interpretation, the time corresponding to the sound to travel a reverberation radius should be assumed as the lower limit of integration of the diffuse sound energy
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Zou, Chenglu, Dongpeng Mo, and Bo Gao. "Seamount Clutter Modeling for Long Range Seabed Reverberation in Deep Sea." Journal of Physics: Conference Series 2486, no. 1 (May 1, 2023): 012099. http://dx.doi.org/10.1088/1742-6596/2486/1/012099.
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Abstract Reverberation clutter induced by discrete strong scatterers is an important reason which will increase the false alarm probability of active detection, which seriously affects the performance of active sonar detection. In this paper, taking seamount as an example, the theoretical modeling and simulation of the clutter in the deep-sea induced by seamount are carried out by using the ray-mode theory. Through ray-mode approximation, the acoustic rays in surface and reverse channels are ignored, a theoretical model is proposed to calculate the seabed reverberation clutter induced by seamounts, and the physical mechanism of how the seabed reverberation clutter is induced by seamounts is analyzed. The results show that reverberation intensity will increase in the location of seamount and induce discrete reverberation clutter. The greater the fluctuation of seamount, the greater the reverberation clutter intensity.
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HANYU, Toshiki. "Mathematical model of reverberation decay in a rectangular room with uneven distribution of absorption." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 268, no. 3 (November 30, 2023): 5987–95. http://dx.doi.org/10.3397/in_2023_0871.
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Based on traditional reverberation theories such as Sabine's or Eyring's theories, the reverberation energy decay becomes linear in logarithmic scale of energy. However, this is valid only in diffuse sound fields. Sound fields in actual rooms are non-diffuse sound field. It has been well known that nonlinear reverberation decay occurs in a rectangular room with uneven distribution of absorption. Hence, reverberation times measured in such rooms are not correspondent with those calculated by the theories. Reverberation theories for such rectangular rooms have been proposed by some researchers. However, these theories have not been sufficiently validated. In this study, a new mathematical model of reverberation decay in rectangular rooms with uneven distributions of absorption is proposed. Most of previous theories contained only exponential decays. The proposed model in this study contains not only exponential decays, but also power law decays.
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Zhao, S. D., Kun Yan, and T. Z. Zhou. "The STAP Method for Moving Sonar Reverberation Suppression." Applied Mechanics and Materials 743 (March 2015): 395–98. http://dx.doi.org/10.4028/www.scientific.net/amm.743.395.
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The theory of full dimension and reduced dimension STAP was introduced. Based on the physical mechanism of reverberation formation, the suppression of moving sonar reverberation and the possibility of improvement of detection performance were analyzed and discussed, and the solutions of several key steps were given. The analysis shows that reverberation suppression using STAP is more difficult than clutter suppression of AEW, but its implementation is possible. The results of simulation show that the STAP method can achieve better detection performance than conventional method. The STAP method can utilize the space-time characteristic of moving sonar reverberation sufficiently, and so is a promising new method of reverberation suppression.
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Johnson, Carole E. "Childrens’ Phoneme Identification in Reverberation and Noise." Journal of Speech, Language, and Hearing Research 43, no. 1 (February 2000): 144–57. http://dx.doi.org/10.1044/jslhr.4301.144.
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This study assessed the effects of reverberation, noise, and their combination on listeners’ identification of consonants and vowels in naturally produced nonsense syllables presented at different sensation levels (re: speech recognition threshold). A secondary purpose of this study was to assess listeners’ identification of voicing, manner, and place of articulation for consonants at 50 dB SL in the reverberation, noise, and combined conditions. Listeners, aged 6–30 years, identified consonant-vowel-consonant-vowel (CVCV) stimuli presented at four different sensation levels (re: speech recognition threshold) of 30, 40, 50, and 60 dB SL in 4 listening conditions: (a) an optimal listening situation (no reverberation, no noise), (b) reverberation only (1.3 seconds), (c) noise only (+13 dB S/N against a multitalker babble), and (d) reverberation plus noise. Results showed that all listener groups achieved maximum consonant identification performance at 50 dB SL. Vowel identification scores were unaffected by SL. Statistical analyses revealed that childrens’ ability to identify consonants varied according to listening condition. For example, childrens’ consonant identification abilities reached adult-like levels of performance at about age 14 years in the reverberation-only and noise-only listening conditions. However, in the reverberation-plus-noise listening condition, childrens’ consonant identification abilities do not mature until the late teenage years. The ability to identify vowels, on the other hand, develops much earlier. A feature analysis of the consonant data showed that for all 3 features (voicing, manner, and place), identification scores were highest in the control condition, similar for the reverberation-only and noise-only conditions, and lowest in the reverberation-plus-noise condition. Voicing was easier for listeners to identify than manner or place of articulation features in reverberation and noise. Taken together, these results suggest that the ability to identify speech in reverberation and noise reaches adult-like level of performance at different ages for different components of the speech signal.
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Yadav, Saurabh, Gaurav Sharma, Sarthak Nag, and Arpan Gupta. "Reverberation time improvement of lecture auditorium: A case study." Noise & Vibration Worldwide 49, no. 1 (January 2018): 14–19. http://dx.doi.org/10.1177/0957456517748448.
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In this study, reverberation time of a lecture auditorium has been analyzed experimentally and analytically. It is well-known fact that reverberation time affects the speech intelligibility and hence should be within the range of possible optimum values. Experiments were performed to calculate the reverberation time of a lecture auditorium constructed at Indian Institute of Technology Mandi (IIT Mandi), for different internal conditions such as furniture and curtains. Experimental results were compared with the theoretically calculated values of reverberation time. It is found that acoustic performance of the lecture auditorium has significantly improved using curtains on the windows and furniture. For further improvement, it has also been suggested to use the carpet on the floor of the auditorium. The theoretical value of reverberation time is also calculated to show the improvement which can be achieved using carpet. The effect of audience on reverberation time has also been studied theoretically.
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Li, Gongyun, Bo Gao, and Jie Pang. "Phenomenon of reverberation intensity oscillation observed in shallow-water reverberation experiment." Journal of Physics: Conference Series 2718, no. 1 (March 1, 2024): 012076. http://dx.doi.org/10.1088/1742-6596/2718/1/012076.
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Abstract Reverberation has always been a disturbance for active sonar. In the Yellow Sea reverberation experiment conducted in July 2014, the motion of the soliton internal wave was recorded by the temperature sensor attached to the vertical array. The effect of the soliton internal wave on reverberation was investigated from both the temperature chain and the reverberation static experiment. Through the processing of the data in this section, it is found that the soliton internal wave can cause the generation of clutter and the oscillation phenomenon of the average reverberation intensity, and the subsequent research can realize the acoustic telemetry to forecast the internal wave and further improve the performance of the active sonar.
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Zhang, Li Cai, and Xiao Juan Tong. "Research on a Model of Reverberation." Applied Mechanics and Materials 321-324 (June 2013): 1117–22. http://dx.doi.org/10.4028/www.scientific.net/amm.321-324.1117.
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Against defects of lacking consideration of air absorption characteristics to the high frequency signal in Schroeder reverberation model, and the more complex structure in Moorer reverberation model, use equiripple Chebyshev approximation criterion to design 4 FIR comb filter with low-pass characteristics and make the FIR filters in parallel, to get a pure parallel reverberation model. This reverberation model considers the absorption characteristics of air to the high-frequency signal, and has a more simple structure.
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Rui, Guo, Lei Liu, Sheng Zhen-Xin, and Song Pu. "A three-dimensional bistatic reverberation model of underwater explosion by interface scattering at variable sound speeds." Journal of Low Frequency Noise, Vibration and Active Control 38, no. 2 (December 12, 2018): 427–40. http://dx.doi.org/10.1177/1461348418816458.
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Underwater reverberation is a main limitation of the sonar performance and thereby the reverberation level estimation becomes crucial. In this study, based on the Lambert law and ray theory, a model for predicting 3D bistatic reverberation performance by interface scattering at linear sound speed profile is established and then verified through the underwater explosion experiments. The Influences of source and receiver positions, and relative sound speed gradient on reverberation performance are further investigated. The results indicate that: (1) the proposed model can predict the short-range mean reverberation level effectively, with the deviation 2–4 dB and describe the whole reverberation level distribution in some details; (2) at the early reverberation phase, the interference effects between the interface scattering sounds are considerable and a dominating interface exists; the counterbalance between the losses by scattering, spreading and medium absorption results in the local high-intensity zones close to corresponding interfaces, respectively; (3) as the sound source moves towards some interface, associated local high-intensity zone gradually expands, while the other one shrinks; if the sound speed approaches are constant, an extra local high-intensity zone will appear between the previous two but with a lower magnitude.
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Choo, Youngmin, Woojae Seong, and Keunhwa Lee. "Efficient Algorithm for Long-Range Monostatic Reverberation in Shallow Water Using Geometrical Ray-Bundle." Journal of Computational Acoustics 24, no. 02 (June 2016): 1650002. http://dx.doi.org/10.1142/s0218396x16500028.
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An efficient algorithm for long-range monostatic reverberation is developed using geometrical ray-bundle as its propagation model. In the standard approach for reverberation modeling, scattered signals are numerically integrated along the rough surface. In this work, the integration along the rough surface is converted to an integration along the delay time of source signal. It can be expressed in an analytic form under the assumption of ignoring time-dispersion effect. Repetitive eigen-ray searches for calculating scattered signals are avoided by using a split-step marching algorithm for the range based on the geometrical ray-bundle. When the bottom is range-dependent, arrival times of scattered signals from the rough bottom at same range is different according to azimuthal angles and they cannot be directly summed in time domain. The reverberation signals along the azimuthal angles are interpolated to obtain new reverberation signals at certain times. They are summed to compute a time series reverberation signal from the rough sloping bottom. The algorithm is applied to problems of reverberation modeling workshop, and its results are compared with those from the standard reverberation algorithm.
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Gao, Bo, Ning Wang, and Hao Zhong Wang. "Investigation of Sea Surface Effect on Shallow Water Reverberation by Coupled Mode Method." Journal of Computational Acoustics 25, no. 02 (March 16, 2017): 1750017. http://dx.doi.org/10.1142/s0218396x17500175.
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The effects of rough sea surface on the long-range bottom reverberation in shallow seas are studied by the coupled mode reverberation theory. The scattering effect caused by irregular rough sea surface is described by couple coefficients. The decaying rules of long-range bottom reverberation level are simulated at different sea states, and the rough sea surface effect on the coherence of distant bottom reverberation is also discussed. It is indicated that irregular upper boundary has changed the propagation effect of the shallow water waveguide, and bottom reverberation, which is dominated among other kinds of reverberation in shallow water, is affected by the sea surface scattering as the increasing sea state. Compared with other literatures, the emphasis of this paper is to present the mechanism of rough sea surface scattering by describing the transfer of energy between different modes, and the details of energy transitions between different modes which are caused by sea surface scattering are presented for different sea states. With the increasing sea state, stronger mode coupling caused by surface scattering would affect the intensity and its space coherence of bottom reverberation obviously.
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Wang, Fangyong, Yeming Jiang, and Shuanping Du. "Study on Doppler characteristics of underwater bistatic reverberation." MATEC Web of Conferences 283 (2019): 03004. http://dx.doi.org/10.1051/matecconf/201928303004.
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Active sonar has two typical types of geometry configuration respectively named monostatic and bistatic like a radar system. In the monostatic scenario, co-located underwater transducers transmit and receive sound energy, while in a bistatic situation the transducers are physically separated. Both object detection and identification can be significantly enhanced through utilization of the additional dimension provided by a bistatic geometry. So, more people care about bistatic scattering characteristics of underwater objects as well as bistatic reverberation in recent years. In this paper, Doppler characteristics of bistatic reverberation generated by moving transmitter and receiver are studied. Theoretical formulism for receiving frequency of bistatic reverberation is derived in case of a tone signal being transmitted. Further analysis shows bistatic reverberation is more complicated than monostatic reverberation when Doppler is concerned. In monostatic case, the Doppler frequency shift of reverberation relates to centre frequency of the tone signal, velocity of the transmitter as well as the arriving direction. While in bistatic situation, it varies not only with the above factors, but also the locations, moving directions, velocities of both transmitter and receiver, and also the arriving time of the reverberation, which makes extraction and utilization of Doppler information more difficult.
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Lewis, Dawna E., Crystal M. Manninen, Daniel L. Valente, and Nicholas A. Smith. "Children's Understanding of Instructions Presented in Noise and Reverberation." American Journal of Audiology 23, no. 3 (September 2014): 326–36. http://dx.doi.org/10.1044/2014_aja-14-0020.
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Purpose This study examined children's ability to follow audio–visual instructions presented in noise and reverberation. Method Children (8–12 years of age) with normal hearing followed instructions in noise or noise plus reverberation. Performance was compared for a single talker (ST), multiple talkers speaking one at a time (MT), and multiple talkers with competing comments from other talkers (MTC). Working memory was assessed using measures of digit span. Results Performance was better for children in noise than for those in noise plus reverberation. In noise, performance for ST was better than for either MT or MTC, and performance for MT was better than for MTC. In noise plus reverberation, performance for ST and MT was better than for MTC, but there were no differences between ST and MT. Digit span did not account for significant variance in the task. Conclusions Overall, children performed better in noise than in noise plus reverberation. However, differing patterns across conditions for the 2 environments suggested that the addition of reverberation may have affected performance in a way that was not apparent in noise alone. Continued research is needed to examine the differing effects of noise and reverberation on children's speech understanding.
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Mason, Michelle, and Kostas Kokkinakis. "Perception of Consonants in Reverberation and Noise by Adults Fitted With Bimodal Devices." Journal of Speech, Language, and Hearing Research 57, no. 4 (August 2014): 1512–20. http://dx.doi.org/10.1044/2014_jslhr-h-13-0127.
Full textAbstract:
Purpose The purpose of this study was to evaluate the contribution of a contralateral hearing aid to the perception of consonants, in terms of voicing, manner, and place-of-articulation cues in reverberation and noise by adult cochlear implantees aided by bimodal fittings. Method Eight postlingually deafened adult cochlear implant (CI) listeners with a fully inserted CI in 1 ear and low-frequency hearing in the other ear were tested on consonant perception. They were presented with consonant stimuli processed in the following experimental conditions: 1 quiet condition, 2 different reverberation times (0.3 s and 1.0 s), and the combination of 2 reverberation times with a single signal-to-noise ratio (5 dB). Results Consonant perception improved significantly when listening in combination with a contralateral hearing aid as opposed to listening with a CI alone in 0.3 s and 1.0 s of reverberation. Significantly higher scores were also noted when noise was added to 0.3 s of reverberation. Conclusions A considerable benefit was noted from the additional acoustic information in conditions of reverberation and reverberation plus noise. The bimodal benefit observed was more pronounced for voicing and manner of articulation than for place of articulation.