In this paper, we propose an intelligent sound field tuning system for home theater systems that includes room acoustic compensation and additive artificial sound field processing. Room acoustic compensation is performed based on the information about room transfer characteristics measured by a three-channel microphone array. With a three-channel microphone array, we estimate the exact angular position, distance, level, and frequency response of loudspeakers. Using this information, the proposed system can compensate the degradation induced by non-ideal loudspeaker arrangement with virtual loudspeaker positioning and binaural energy level alignment algorithm. After room acoustic compensation, additive artificial sound field processing is performed for more realistic spacious impression. For artificial sound field processing, directional impulse responses are measured in real acoustic space by three-channel microphone array.
Climate change impacts the urban environment and landscape changes worldwide. To understand how South Korean citizens perceive these changes and what they expect for the future landscape, this study analyzed urban residents’ perceptions through text mining. Data related to the keywords “future landscape”, “future environment”, “well-being”, and “climate change” were collected from July 2020 to July 2021 from the Korean search engines Naver, Daum, and Google using the tool TEXTOM. Keywords, importance, and related words were derived through word frequency, TF-IDF, and N-gram analysis. CONCOR analysis was used to derive the meaning and relevance of the words. In “future landscape”, results showed a high frequency of the words “complex”, “apartment”, “future value”, and “sale”, and the connection strength was higher between “complex”, “landscape”, and “future value”. In “future environment”, “eco-friendly” showed the highest word frequency, and the words “New Deal”, “hydrogen” and “mobility” showed a high frequency and correlation. For “well-being”, “Green Cross” (a well-being-related company) showed the highest frequency, and the connection strength between satisfaction indexes was high. For “climate change”, “response” showed the highest frequency, and the connection strength between “carbon-neutral”, “UN-convention”, and “plan-establishment” was high. These results showed that South Koreans associate landscaping with the value of apartment complexes, that they expect solutions to mitigate climate change impacts with green and eco-friendly strategies, and lastly that well-being-related companies are receiving a great deal of public attention. Thus, it is expected that the results will help plan effective landscaping approaches to respond to environmental changes.
Numerous investigations have demonstrated that diffuse reflection is one of the most important factors in predicting room acoustics by computer simulation. Recent studies have suggested several computational algorithms in order to account for diffuse reflections in the ray-tracing or beam-tracing method. In this study, a computational algorithm for the calculation of diffuse sound reflections in the image method is suggested and a computer simulation system is developed based on the suggested algorithm. The methodology adopted in our computer simulation system is similar to the extended radiosity method, which was developed for computer graphics. Various descriptions of room acoustics, including spatial distribution of image sound sources, impulse responses and other commonly used room acoustical measures, can be obtained from the MLS based monaural room acoustics measurement system. The measured results in a midsized rectangular classroom with/without chairs on the floor were compared with the predicted results using the computer simulation in which diffuse reflection coefficients of the floor were varied. [Work supported by Korean Research Foundation Grant KRF-1999-1-310-004-3.]
In automobile space, we experience sound coloring of reproduced sound quite differently from large spaces such as concert halls. This is assumed to be due to the well-separated acoustic modes in the low frequency range up to the relatively high crossover frequency. Such unwanted sound coloring can be reduced through equalization of the well-separated modes. However, it is not a simple process as binaural responses are different for every person and drivers are likely to move their head during driving. We introduce a novel approach, based on minimum phase inversion, to the equalization of the low frequency response in order to compensate for the coloring. We then compare the proposed approach with the conventional least squares based inversion and attempt to show the superiority of this approach through experimental and listening test results.
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