An algorithm of audio signal dccorrclation is proposed. The algorithm is based on a pair of all-pass filters whose responses match with a pair of reciprocal maximal length sequences (MLSs). Taking advantage of the cha...
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ISBN:
(纸本)9781622766031
An algorithm of audio signal dccorrclation is proposed. The algorithm is based on a pair of all-pass filters whose responses match with a pair of reciprocal maximal length sequences (MLSs). Taking advantage of the characters of uniform power spectrum and low-valued cross-correlation of reciprocal MLSs, the filters create a pair of output signals with low cross-correlation but almost identical magnitude spectra to the input signal. The proposed algorithm is applied to broadening the auditory source-width and enhancing subjective envelopment in multichannel sound reproduction. Preliminary psychoacoustic experiments validate the performance of the proposed algorithm.
Design for acoustic performance for an interior fluid domain requires accurate description of boundary materials' specific acoustic impedance. The standard approach for the estimation of this material characterist...
Design for acoustic performance for an interior fluid domain requires accurate description of boundary materials' specific acoustic impedance. The standard approach for the estimation of this material characteristic is the two-microphone, impedance-tube method. Modifications to the processing of the sampled acoustic field have been proposed to allow for more general test geometries. While analytical methods may be applied to a small class of ideal geometries, numerical methods provide greater geometric flexibility. In general, solutions to the wave equation forward problem are found from boundary element, finite element, or finite difference methods. The inverse problem of parameter estimation is solved by evaluating accuracy of prediction of the acoustic field for given distributions of the specific acoustic impedance parameter against observed data. In this presentation a Bayesian-network sampling approach is used to estimate specific acoustic impedance of a micro-perforated panel in an impedance tube test geometry. The choice of geometry and material allow for direct comparison to the two-microphone, impedance-tube method within the appropriate frequency range, and a theoretical model for the material beyond that frequency range. The potential to extend the frequency range of operation of the impedance tube is explored. Sensitivity of the method to nuisance parameters is discussed.
Acoustical coupling until now has basically been studied to define the peculiar sound field within acoustically coupled enclosures in which multiple-slope energy decays can often be observed. The key concern of this s...
Acoustical coupling until now has basically been studied to define the peculiar sound field within acoustically coupled enclosures in which multiple-slope energy decays can often be observed. The key concern of this study is to reveal the potential of multiple-slope energy decay formation in over-size single space structures with particular geometry and distribution of materials in different acoustical performance characteristics. Specifically, multiple dome superstructures, composed of one central dome supported by semi-domes and transitional elements, are selected for the case studies. The interpretation of the acquired data is carried in order to broaden the definition of “the coupled volume system” with an emphasis on invisible sources and apertures of acoustical coupling in a “single volume system.” The methodology of the research involves joint use of in-situ acoustical measurements, acoustical modeling/simulation methods, and computational analyses. Bayesian analysis approach is applied in quantifying multiple-slope decay parameters. Initial results for selected cases indicate double and triple slopes for field tests and even more slope natures for simulations at various frequency bands. Future work aims to elaborate the mechanism of multiple-slope decay occurrence by energy feedback and distribution analysis.
Window displays, as a part of selling strategies, not only convey the type and positioning of mechanize, but also the promotional strategies and corporate images. The study uses window displays for clothing to examine...
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Window displays, as a part of selling strategies, not only convey the type and positioning of mechanize, but also the promotional strategies and corporate images. The study uses window displays for clothing to examine patterns, selling strategies, merchandize types, and target groups. It investigates the effects of design elements on the customers perceptual responding to configurations. The theoretical framework bases on marketing concepts, visual perception principles, Gestalt psychology, and design's principle and elements. Research found that 14 factors in the design affected to perception. The study perception indicates that purchasing desire and attraction had more relation.
Speech from a target speaker reaches a listener via multiple paths in a room due to room reflections. As sound waves from the target speaker approach the listener, degradation to the signal is caused by ambient noise ...
Speech from a target speaker reaches a listener via multiple paths in a room due to room reflections. As sound waves from the target speaker approach the listener, degradation to the signal is caused by ambient noise and reverberant energy. The speech transmission index (STI) is a commonly used metric for predicting speech intelligibility accounting for both noise and reverberation. This metric, however, is a monophonic measure that does not take into consideration binaural cues used for unmasking undesired effects. As a result, using the STI on its own tends to under-predict intelligibility under binaural listening conditions. The proposed research aims to improve speech intelligibility predictions with the presence of room effects by implementing a psychophysical binaural model as a front-end to the STI calculation. The equalization-cancellation (EC) theory is applied to spatially unmask noise, while late incoherent reverberant energy is suppressed by applying a weighting function based on interaural coherence. Preliminary comparisons between listening tests and model predictions reveal promising results, indicating a useful tool in acoustical planning in addition to further study into binaural suppression processes.
According to the advancement in internet and web-based application, the survey via the internet has been increasingly utilized due to its convenience and time saving. This article studied the influence of five web-des...
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A method to estimate the physical parameters of rigid-frame porous materials through measurement of the acoustic impedance of such materials is presented. Porous materials are widely used as sound absorbers in many in...
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This study investigates the effect of head movement in the evaluation of listener envelopment [LEV] and apparent source width [ASW] under 15 different concert hall conditions simulated over eight loudspeakers using Vi...
ISBN:
(纸本)9781618393968
This study investigates the effect of head movement in the evaluation of listener envelopment [LEV] and apparent source width [ASW] under 15 different concert hall conditions simulated over eight loudspeakers using Virtual Microphone Control. The conditions consist of varying ratios of front-to-back energy and varying coherence levels of cross-correlated reverberant energy. Head movements are monitored in terms of angular rotation using a head tracker while listeners are prompted to assign subjective ratings of LEV and ASW. The tests are repeated while listeners are asked to keep their heads fixed. Head movements are analysed and results of the tests are compared.
Aerogel is a material with unique nanoscale properties. In monolithic form aerogel is too costly to be practically used in acoustic applications. Recently a cost-effective technique for producing granular aerogel has ...
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ISBN:
(纸本)9781618392800
Aerogel is a material with unique nanoscale properties. In monolithic form aerogel is too costly to be practically used in acoustic applications. Recently a cost-effective technique for producing granular aerogel has been developed, but the acoustic properties of granulated aerogel were not well known. The normal incident acoustic absorption and attenuation of three configurations of granulated aerogel have been determined by means of the transfer function and the transmission matrix methods of measuring normal induct acoustic properties: using the granules as a loose fill, woven into glass fiber blankets, and bound into a solid plate with a poly-vinyl acetate binder. Measurements were conducted using a 64 m impedance tube, the design of which is also discussed.
Conventional metrics for predicting speech intelligibility are commonly described using the speech intelligibility index (SII) and speech transmission index (STI)--both of which are calculated using a monophonic signa...
Conventional metrics for predicting speech intelligibility are commonly described using the speech intelligibility index (SII) and speech transmission index (STI)--both of which are calculated using a monophonic signal. Under binaural conditions, these predictors often underestimate intelligibility due to the fact that beneficial binaural cues for unmasking detrimental effects are not accounted for. Beutelmann et al. [J. Acoust. Soc. Am. 127, 2479-2497 (2010)] proposed a binaural speech intelligibility model that determines the SII after suppressing spatially-separate noise using the equalization-cancellation (EC) process. This research expands on previous work by extending the model to analyze auditory scenes with more complex room acoustics, namely reverberation. In order to account for speech intelligibility degradation in the presence of room effects, the SII calculation is replaced by the STI. The current work also incorporates binaural release from reverberation by introducing an additional reverberation suppression mechanism into the model based on interaural coherence. The use of speech intelligibility metrics as an objective form of measurement may be used as a means to further understand binaural suppression processes within various room acoustic configurations through subjective listening tests.
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