Evaluation And Prediction On Acoustic Environment In Large Dining Spaces

As an important component of urban public spaces,dining spaces not only provide people with dining places in daily life,but also are important places of social and public gatherings and carriers of daily communications and activities for people.As an important component of the overall dinning environment,sound environment in dining spaces determines the comfort of the overall environment in dining spaces and affects the dining satisfaction and behavior intention of diners.Therefore,providing the sound environment with appropriate comfort for diners is an important issue of creating a high-quality dining environment and improving the service quality of dining.However,there are few studies on the sound environment of dining spaces at present in China.This research adopts the method of combining qualitative research with quantitative research to study the sound environment of dining spaces and guides further quantitative research through the result of qualitative research.In the aspect of qualitative research,this research selects grounded theory research method and aims to establish the theoretical model of “influence factors of evaluation on the sound environment of dining spaces”,which will provide a theoretical basis for preparing questionnaires on the sound environment of dining spaces in quantitative research.In the aspect of quantitative research,this research selects typical large dining spaces as research objects,adopts the method of combining field questionnaires with objective actual measurement to carry out surveys,conducts studies from the aspect of acoustic preference and comfort through applying the statistical method and aims to reveal the influence factors of acoustic preference evaluation and acoustic comfort evaluation of diners.Based on the obtained result of quantitative research,this research finally selects BP neural network technique and multivariable linear regression model to build prediction models for evaluation on the sound environment of dining spaces respectively.Firstly,this research establishes the theoretical model of “influence factors of evaluation on the sound environment of dining spaces”,which is composed of 4 main categories:“individual differences”,“sound expectation”,“acoustic comfort”,“articulation”.In the aspect of evaluation on the acoustic preference of dining spaces,results showed: Diners expected to feel the sound environment atmosphere of recreation and entertainment with a sense of participation and interaction in dining spaces;the sound pressure level of background noise in dining spaces was 65 d B to 80 d B,but most of diners(30% to 70%)thought it was noisy and very noisy;the sound pressure level of background noise,demographic/social factors and noise level of various independent sound sources were influence factors of diners ’ evaluation on noise level.Evaluation on the noise level of various independent sound sources was significantly and positively correlated with evaluation on the acoustic preference of sound sources.Under the action of different types of sound sources,including background sound,language sound sources,behavior and activity sound sources and mechanical noise,diners showed a high degree of preference for background sound in keynote sound and language sound sources produced by diners,and expressed a low degree of preference for behavior and activity sound sources and mechanical noise in foreground sound and key sound.Based on acoustic preference evaluation,typical sound sources in dining spaces were sorted as follows: background sound,footstep,speech sound of other diners,speech sound of staff,impact sound of tableware and fan sound of smoke ventilators(air-conditioners)from high to low.In the aspect of demographic/social factors,whether dine out frequently,gender,occupation and income showed significant differences in evaluation on the acoustic preference of different sound sources.In the aspect of evaluation on the acoustic comfort of dining spaces,results showed: Evaluation on acoustic comfort in dining spaces had an influence on diners’ evaluation on the comfort of the overall dining environment;background noise was an important factor influencing the acoustic comfort of din ers.Under the action of composite sound sources,the threshold range for the sound pressure level of background noise was from 70 d B to 75 dB when the evaluation of diners on acoustic comfort was acceptable.Under the action of various independent sound sources,acoustic comfort of sound sources including background music,speech sound of other diners,impact sound of tableware and so on exerted an influence on the evaluation of diners on the acoustic comfort of the overall dining environment.When there was background music in background noise,diners’ evaluation on acoustic comfort was higher.The loudness,articulation,noise level and preference degree of various independent sound sources were influence factors of diners’ evaluation on the acoustic comfort of sound sources.In the aspect of demographic/social factors,gender and whether dine out frequently had a significant impact on diners’ evaluation on the acoustic comfort of the overall dining environment.In the aspect of comparing and studying evaluations on the acoustic comfort of overground/underground dining spaces,the acoustic comfort of overground dining spaces was superior to that of underground dining spaces;compared with overground dining spaces,the sound pressure level of background noise had a greater influence on the acoustic comfort of underground dining spaces;however,evaluations on the acoustic comfort of overground /underground dining spaces showed no significant differences when the sound pressure level of background noise was within the acceptable threshold range of acoustic comfort of diners.Finally,Prediction model for evaluation on the sound environment of dining spaces takes the known sound environment conditions(measured sound pressure level of background noise)in dining spaces and individual characteristics(demographic/social factors)of potential diners to predict diners ’ evaluation on the overall sound environment of newly-built or to-be-rebuilt dining spaces.Prediction effects of established models are acceptable.The prediction effect of BP neural network prediction model is superior to that of multivariable linear regression prediction model.The prediction models established in this research can help architects to appropriately grasp the sound environment of dining spaces at the design stage and select the optimal design scheme of dining spaces from the aspect of sound environment.