The main requirement for speech is clarity and intelligibility, but it also requires a certain degree of loudness to make it sound unobtrusive. At the same time require a balanced spectrum, not distorted. For music, in addition to clarity (clarity) and loudness requirements, there are fullness, sense of space and balance and other requirements. In the meantime, the common premise of both voice discourse and music discourse is to avoid sound quality defects. Sound quality defects mainly refers to noise interference, echo interference and chatter echo and so on.

      Linguistic clarity refers to the percentage of speech signals (words or syllables) that are unambiguously linked to the correct identification by the audience through the transmission of the halls (and sometimes the transmission of loudspeaker systems). The degree of intelligibility refers to the phonetic signals that have the meaning of words, which can be heard clearly by the audience through the hall. Due to the phonetic information of the word meaning, the listener can deduce the inference from the semantic association before and after, so the intelligibility is often higher than the definition. Voice audible requirements Understandability reached 95% or more, sharpness reached 85 or more. Hearing is laborious and difficult to understand when the sharpness is below 60%, and between 60% and 80%, the listener needs to concentrate to understand the content of the speech. Subjective evaluation of indoor Chinese syllabity subjective evaluation test is to find some listening auditions with normal hearing, so that they sit in the hall, from a clearly articulate, pronunciation standard person, read a by 20 with different vowels of Chinese characters The pronunciation of the word table, by the audition in the corresponding word list to select tick. The discriminant list consists of 20 × 5 Chinese characters, and one Chinese character corresponding to each vowel has 5 Chinese characters to choose from. For example, the pronunciation of the word table corresponding Zhuang Zi, a window, Wang, Zhuang, light, double 5 Chinese characters to choose from. After the test is completed, calculate the percentage of words listened by each listener to the total number of words, together with the guesswork correction, the syllable definition of each listener. The average of all auditioners' definition is the language syllabibility of the hall.

      Fullness refers to the listening room in the hall, due to the reflection of the interface and the direct sound from the enhance and contrast role. The lack of reflex sound quality environment is dry and quiet. Sometimes the bass reflex-rich sound quality is called a warmth, while the middle and high reflections sound rich sound quality is called activity.

      The clarity of sound quality is also called Clarity. It can be divided into horizontal resolution and vertical resolution. The former refers to the succession of musical notes separated and definable level, that can hear the rapid and consistent melody playing the passage. The latter refers to the degree of discernibility of the notes of the voices playing simultaneously, ie, the transparency and the sense of hierarchy of the music.

      Music and balance, refers to the balance of low, medium and high treble and coordination, that is, natural tone is not distorted, not distorted. The spatial sense of music has a broader meaning and may include the sense of outline of the sound source, the sense of three-dimensional, the horizontal sense of broadening and the sense of depth of the sound source, and the sense of surround of music, that is, the feeling of being surrounded by music.

      The intimacy of sound quality refers to the feeling of listening in the smaller auditorium, which is the auditory impression of the size of the auditorium.

      It is generally accepted that good sound quality should have four characteristics: (1) an appropriate balance between fullness and sharpness; (2) a suitable loudness; (3) a sense of space; (4) Good sound, that is, low, medium and high frequency of each part of a good balance, the sound is not distorted, not distorted.

      Although the quality of the hall is ultimately judged by the subjective evaluation of quality, but in order to guide the design of the hall sound quality, as well as the more convenient to measure the quality of the hall, we must also explore and explore a number of subjective evaluation significantly related to both measurable Calculated physical indicators, based on them for objective evaluation of sound quality. After a century of acoustic research, found that the following a number of physical indicators of the hall to determine the sound quality is of great significance.

      Mixed to the time T60, or recorded as RT (Reverberation Time), is the first and most important sound quality evaluation of physical indicators. The reverberation time is related to the fullness and sharpness of the sound quality. In general, the longer the reverberation time, the fullness increases, while the sharpness decreases. This is because the reverberation takes a long time, and for the performance of listening, both the onset of the sound and the natural decay may be submerged in the reverb sound and become blurred. There is a similar situation for speech. Reverberation time too long, so that the language blog heard obscure. However, if the reverberation time is too short, it indicates that the reflection of each interface in the hall is too weak and the sound absorption is too large, which will affect the fullness of sound quality.

      In general, for the language hearing-based halls, such as classrooms, lecture halls, theaters, etc., do not want reverberation time is too long, preferably about 1s; and for listening to music-based halls, such as concert halls And so on, you want longer reverb time. For the language hearing and music hall, such as the opera house, multi-function hall reverberation time, desirable compromise, for 1.3-1.5s. In short, the best reverberation time must be chosen for the main purpose of the specific toolroom in order to achieve a proper balance of fullness and sharpness. Reverberation time is proportional to the volume of the hall, therefore, when the hall total sound absorption volume, the greater the volume, the longer the reverberation time. When designing the sound quality of halls, especially for view-oriented buildings with natural sound performance, the acoustic energy is extremely valuable due to the limited acoustic power of the noise of musical instruments and people. Therefore, such halls (such as concert halls, such as concert halls, Lecture) are advocating the design as much as possible or less use of sound-absorbing materials. At this time the audience's total amount of absorption to account for the auditorium volume 2/3 or even 75%. When the total number of viewers is determined, the amount of sound absorption of the audience is basically determined, so that the total amount of sound absorption in the hall can be generally determined. At this time, the volume of the hall, especially the influence of each volume (ie, the volume of the hall divided by the total number of visitors), has a decisive influence on the reverberation time.

      Hall volume, especially each volume, does not affect the hall of the Central Committee. Loudness depends largely on the share of sound energy each viewer receives. Therefore, it is proportional to the size of acoustic energy density. Acoustic energy density varies depending on the sound source sound power, on the other hand, depends on the volume of the hall. The greater the acoustic power, the greater the acoustic energy density, the greater the acoustic energy density; the larger the hall volume, the smaller the acoustic energy density, so the loudness is smaller. Therefore, especially for the auditorium with natural sound, there should be some restrictions on the volume of the auditorium in order to ensure sufficient loudness. When these limits are exceeded, a sound reinforcement system should be considered.

      When the direct sound spreads close to the auditorium, due to the auditorium on the sound waves absorbed, there will be additional attenuation. In addition, due to the regular arrangement of hall seats, the sound waves in a certain frequency range are destructively interfered, resulting in further attenuation. This effect is called seat absorption trough effect, usually occurs in the low frequency band. As occurs between 80-250Hz. The wavelength of the maximum absorption frequency is approximately 1/4 of the height of the seat back. This effect occurs whether or not there is an audience. Due to the seat absorption effect, the direct sound in a certain frequency range will be further attenuated. Direct high-frequency sound in the composition, but also due to the attenuation of air absorption and attenuation. This phenomenon is more significant when the hall is larger and the distance is longer. China Building Environment Acoustics Network

      In addition, the voices of human and musical instruments have a certain point, the higher the frequency, the more obvious the directionality. When the audience deviates from the sound source sound radiation from the main axis angle is greater, will feel significantly weakened high-frequency sound, thereby reducing the sound brightness and language clarity. Therefore, in body design, should be fully aware of the characteristics of the direct sound propagation and attenuation, so that the audience can fully receive the direct sound energy. Reduce direct sound energy and reduce the additional attenuation of direct sound energy transmission.

      Longitudinal length of the hall should also be controlled, generally should be less than m. For movie theaters, the vertical length should be less than 40 m so that the faraway audience can not feel the sound out of sync with the image. When the audience seats more than 1500, should adopt a cantilevered floor; when the audience seats more than 2500, should adopt two or more floors. By taking the above measures to shorten the distance of direct sound transmission, so as to ensure that the farthest audience can hear clearly.