Primary Study On The Acoustic Characteristics Of Phonetic Sound And The Allowable Volume Of The Classroom Without Loudspeaker System

School is the main place for teachers and students to work,study and live.The quality of the built environment affects the health of teachers and students and the quality of teaching,but for a long time,the quality of the school building environment has not been paid enough attention,and the impact of the learning environment on teachers and students has been ignored.This article takes the vocal characteristics of the teaching language as the research object.Eight male and female subjects were selected and measured in an anechoic room to study the effects of languages,vocal intensities,vocal materials,vocal rates,and gender of male and female on voice characteristics of teaching.The research content mainly includes:(1)Using long-term average spectrum(LTAS)analysis method,the subjects vocalize in two languages,Chinese and English,in an anechoic room,at three vocal strengths: large,medium,and small,and at three vocalization rates: normal,fast,and slow.When reading three different vocal materials separately,the equivalent sound pressure level(SPL)and frequency characteristic curve are continuously at 0.3m,and the influence of different sounding situations on the sound frequency characteristic curve of the language is analyzed;(2)With reference to international standards,using spherical brackets in an anechoic room,using 20-channel measurement technology to test the sound power level and sound power level spectrum of the teaching language under different sounding conditions;(3)Based on the sound power level of the teaching language,take rectangular classrooms and square classrooms as examples,analyze from the perspective of SPL,and estimate the maximum allowable volume of natural sound classrooms.Research indicates:(1)The SPL of the teaching language has little relationship with the content of the vocal materials.For different languages,the SPL of Chinese is higher than that of English,and the dynamic range is also slightly higher.The language,the vocal intensity,and the gender of male and female have a greater influence on the frequency characteristic curve,while the vocal materials and the vocal rates have less influence on the frequency characteristic curve.(2)The total sound power level of Chinese is 61.73-73.37 d B,and the total sound power level of English is 60.88-72.83 d B.The total sound power level and dynamic range of the two languages are not much different.The range of male total sound power level is 60.88-73.37 d B,and the range of female total sound power level is 61.73-72.76 d B.The total sound power level and dynamic range of male and female speakers are the same.The languages,vocal materials,and vocal rates have little effect on the energy concentration frequency range.The sound intensity is increased,and the energy concentration frequency band moves to the high frequency band.And the energy concentration frequency range of female is more high-frequency than male.(3)Based on the SPL control,the rectangular classrooms are 11.7m,6.3m,3.3m in length,width and height respectively,and can accommodate 72 students.The interior volume of the classroom is about 215m~3,and the volume of each is 3.00m~3.The length,width and height of the square classroom are 8.1m,7.5m,and 3.6m respectively,and can accommodate 40 students.The internal volume of the classroom is about 220m~3,and the volume of each room is 5.50m~3.