Research On Acoustic Demands And Acoustic Scene Towards Intelligent Control

Population aging has become a very serious social problem in China,and facilities for the elderly have developed rapidly.However,the lack of consideration for acoustic environment in these facilities in China not only affects the quality of life of the elderly,but also affects their physical and mental health.At the same time,the development of artificial intelligence technology provides the possibility for more accurate intelligent control of the acoustic environment.Therefore,in order to provide more accurate,more efficient and more flexible control of the acoustic environment of the facilities for the elderly,it is necessary to study the acoustic demands of the elderly and the characteristics of the acoustic scenes in these facilities.As for acoustic demands,based on semi-structured interview questionnaire survey and sound pressure level measurement in the field,this study deeply explores the basic characteristics of acoustic demands of elderly people in six typical facilities in northern China,as well as the influence of objective environment,subjective psychology and demographic factors.The results suggested that almost half of the interviewees chose not to add or abate any sound.For the remaining participants,the addition of mainly soothing music to the environment was required,indicating a considerable preference for it over natural sounds,stimulating music,and other sounds.In terms of objective environment,activity type was an important factor influencing acoustic demands,in that playing ball games and sitting still tended to engender demands for the addition of sounds.An analysis of the number of people in a room showed that if that number reached 12,demands for the abatement of sounds increased sharply,particularly for the sound of people talking.For sound pressure level,the higher the indoor equivalent sound pressure level(LAeq),the less need the elderly have to add natural sounds and the more need they have to abate the sound of people talking,especially when the LAeq is greater than 69 d B.In terms of subjective psychology,acoustic preference has a significant impact on demands for the addition of sounds.The more the elderly like the overall acoustic environment of pension facilities,the more they want to add natural sounds and the less they want to abate activity sounds.However,the correlation analysis between sound preferences and acoustic demands for the same types of sound shows that sound preferences do not always exert effects on the degree of acoustic demand.In contrast,age,gender and occupation type all exert effects on demands for the abatement of sounds.On this basis,intelligent prediction models for positive and negative acoustic demands of the elderly are obtained.As for acoustic scenes,based on the collection of sound samples in the field,acoustic scenes in pension facilities were classified according to the characters of the sounds and the behavior characteristics of the elderly,and one type of acoustic scene named as nonmusical activity sound scene was chosen as the research object,which included four specific acoustic scenes of playing table tennis,mahjong,billiards and Chinese chess,respectively,since this type of acoustic scene is in need of and also suitable for intelligent control of the acoustic environment.Spectrogram,MFCC and formant ratio features were analysed and compared,and the results showed that the most significant difference in sound features among four non-musical activity sound scenes occurs in formant ratio feature.Moreover,the ratio of F3 to F4 is the most notable formant ratio feature that could distinguish all of the four activity types.On this basis,this study analysed the effects of acoustic disturbance and sound density on the formant ration features of acoustic scenes,respectively,and the results showed that according to the tendency and the orientation of the regression curve of formant ratio,the interference of speech sound mainly exerted effects on the ratio of F1 to F3,whereas the interference of chorus sound mainly exerted effects on the ratio of F3 to F5.In addition,sound density had a great influence on the characteristics of formant ratio.The regression curve of formant ratio of low-density sound had a notable upward translation in a small range,relative to that of high-density sound,and only the ratio of F4 to F5 was not significantly affected.On the basis of studying acoustic demands and acoustic scenes,this study built the basic framework of intelligently controlling the acoustic environment in facilities for the elderly,the functions of which included the detection of indoor environment,the estimation of real-time acoustic demands of the elderly,and an automatic adjustment of the indoor acoustic environment.Then,a scheme that could help realise the intelligent control system was put forward by demonstrating the kernel mechanism and engineering implementation method.In the end,based on the results of studying acoustic demands and its influencing factors,design strategies of functional layout,room size and soundscape for facilities for the elderly were obtained.The research results of this paper theoretically provided a new angle for applying intelligent technology to China's care facilities,which is conducive to the improvement of the indoor acoustic environment quality as well as the living standards of the elderly,and provided suggestions and help for architectural and interior design of facilities for the elderly in future.