Research On Acoustic Environment Of University Laddre Classroom And Its Improvement Strategy

Nowadays,With the expansion of enrollment in colleges and universities in our country,the number of students in colleges and universities has increased dramatically.Universities and colleges have begun to expand or renovate a large number of teaching buildings on the original campus to meet the needs of students' growth and teaching.However,the blind expansion has made the problem of the acoustic conditions of the classroom unsatisfactory.The bad acoustic environment will affect the emotions of the teachers and students to varying degrees,and then affect the teaching quality and teaching activities of the school.This article takes the college ladder classroom as the research object,through field tests,questionnaires and computer simulations,aims to understand the status quo and existing problems of college ladder classrooms,and propose solutions to the problems.The research method used in this paper is based on the literature research to carry out field acoustic environment test,questionnaire survey and computer simulation.The objective acoustic environment data of the aisle classroom were obtained through field tests.Subjective data were obtained through questionnaire survey.The status quo and problems of the classroom were summarized,and the data base was provided for simulation.The strategy for improving the problem was obtained through simulation.First of all,taking the university ladder classroom as the research object,we studied the ladder classrooms in Harbin and classified the ladder classrooms with the literature,and measured the acoustic environment of the typical classrooms in Harbin,including the background noise,the sound pressure level and the reverberation time.,STI value,EDT value,through the comparison with the standard summary of the existence of a ladder classroom problems.Combined with the questionnaire survey,the students' satisfaction with the acoustic environment of the classroom was evaluated,and the factors affecting the satisfaction were analyzed.The students' learning efficiency was investigated,and the factors influencing the learning efficiency were analyzed.Finally,a correlation analysis was conducted between the actual measured data and the subjective data of the questionnaire survey.Secondly,based on the measured data,a lecture hall model was established and simulated in different plane forms,different seat arrangements,different enclosure materials,and different spatial heights.The acoustic environment characteristics and differences in different situations were summarized.The degree of improvement of the acoustic environment in the program,and based on the simulation results,a strategy for improving the sound environment in the lecture hall was proposed.The average indoor background noise of all classrooms was found to be between 29.2 and 42.0.It was in line with the requirement that the background noise value of the school building should not exceed 45 d B.The indoor T30 showed a downward trend with increasing frequency.The airspace T30 of the aisle 500 ~ 1k Hz is mostly between 2s and 3s,which does not meet the requirements of the "Code for Sound Insulation Design for Civil Buildings".Therefore,using 125 to 500 Hz as the focus frequency band for reducing reverberation time can effectively reduce classroom reverberation time.Through a questionnaire survey,it was found that although the current state of the amphitheatre classrooms does not meet the needs of the majority of students,overall,students' evaluation of learning efficiency in the academy is at an intermediate level,and nearly 30% of the students think it is unclear.In the classroom content,60.8% of the students think that the seat position affects their evaluation of the classroom and become the largest factor;by summarizing the correlation between the subjective evaluation and the objective acoustic environment,it can be seen that there are five objective parameters.The correlation is strong,but the objective factors are not all direct effects and subjective factors,but indirectly affect the subjective feelings by affecting other factors.It is found through simulation that changing the shape of the amphitheatre classroom has little effect on the reverberation time and does not affect the sound pressure level by more than 1 d B.However,when the current back wall is tilted,the indoor sound field can be made more even and the seat arrangement mode can be changed.The influence of pressure level is not more than 0.5d B,and the influence on reverberation time is also small,among which is 3.23s> arc 3.04s> 2.94 s parallel,the effect of changing the spatial height on the sound pressure level and reverberation time in the room All are small.As the height increases,the average sound pressure level in the room decreases,but it also increases the reverberation time.Changing the material of the envelope can effectively reduce the reverberation time of the room.Five kinds of sound absorption materials are used.The reverberation time range of 500 ~ 1k Hz is in the range of 0.37 ~ 0.62.It satisfies the requirements of "Code for Sound Insulation Design for Civil Buildings".The program with the highest average sound absorption coefficient of materials has the highest verbal clarity in the room.Therefore,it is necessary to improve the classroom.Indoor acoustic environment,changing the material of the envelope structure is a cost-effective method.After research,the reverberation time is too long in the aisle classrooms.Nearly 30% of the students think that they cannot hear the contents of the classroom.To improve the acoustic environment in the interior,and to change the architectural plane and space height,change the envelope material The best way to improve this problem,this result can provide reference and help for the design of the academy.