I. General situation of conference sound reinforcement system

 

 

 

The application of conference sound reinforcement system covers almost all the daily activities of foreign affairs reception, news release, technical forum, meeting exchange, etc. Therefore, conference sound reinforcement system has become an indispensable part of the construction, sometimes even an important part of the whole project completion and acceptance.

 

 

 

There are many forms of meetings: lecture, report, discussion and remote conference. Because the number of participants is different, the size of the venue is different, and the functional requirements are different, the sound reinforcement system of the conference will vary greatly and in different forms.

 

 

 

The function perfection of the conference system, not only the venue environment to pay attention to decoration aesthetic visual effect, but also the pursuit of practical function of audio-visual effect, beautiful decoration and good sound quality of the venue to allow the audience to enjoy spiritually.

 

 

 

The most important thing of conference system is its practicability and reliability. In the meetings before the 1980s, due to limited conditions, the mode of information dissemination was single, and only language amplification was considered. That is to say, the speaker's voice is amplified through sound reinforcement so that more people can hear it.

 

 

 

Since the 1990s, with the popularization of multimedia technology, large screen has been widely used as a display means in conferences, and the broadcasting of related audio and video materials has been more and more used in conferences. Therefore, the conference system should consider not only the language amplification, but also the playback and storage of audio and video signals.

 

 

 

With the development of the times, people are increasingly pursuing high-level and high-quality! Psychoacoustics tells us: people's perception and appreciation of sound has a process of development from low to high, from perception to rationality, and listeners gradually establish the external image and internal image of sound in the process of thinking about perceiving sound effects, which is The perception of some images unconsciously influences people's thinking and judgment of voice. The surface image stimulates the listener, while the inner feeling gives people emotional changes. This is the connotation of psychology.

 

 

 

Therefore, the development goal of conference sound reinforcement is to convey the feelings of speakers. Not only through the speaker's language content as the carrier, but also the emotions expressed by the speaker's language are more appropriate to the audience, so that the speaker's voice can truly reach the effect of infecting the audience's emotions.

 

 

 

However, some people think that the technical difficulties and requirements of conference sound reinforcement are not high. They think that the conference sound reinforcement system is very "simple" and do not pay attention to and research. The venue presents a general and routine. However, the sound amplification of conference acoustics has its particularity and complexity, which implies great technical difficulties.

 

 

 

II. Basic knowledge of conference sound reinforcement system

 

 

 

The human voice is mainly produced by the vibration of vocal cords. The characteristics of language are discontinuous and transient, and its pitch and timbre are determined by the interaction of fundamental frequency and harmonics of language itself. The sound energy density of Chinese is generally concentrated between 200 Hz and 700 Hz. The male vocal cords are longer and thicker (i.e. the structure of the sound source itself), and the audio frequency is produced. The average bass frequency (pitch-tenor bass average) is about 230 Hz (bass can be as low as 60 Hz and soprano can be as high as about 1 kHz). The harmonic frequencies produced by language pronunciation can reach over 6 kHz, the sound pressure level is 60-70 dB, and the dynamic frequency is 80 dB.

 

 

 

The characteristics of Chinese language are that its tone is melodious and melodious, and its logical stress fluctuates greatly. Poetry or American prose are all catchy, melodious, powerful and rhythmic. In Chinese sentences, stress, mood and rhythm, we should analyze the speaker's pronunciation characteristics, as well as the frequency. We should adjust the pronunciation with high or low frequencies to get the best sense of hearing. Chinese voice, because of the different tapes, the gap between men and women is large, men and men, women and women are different, Chinese pronunciation energy is concentrated in 200 Hz-700 Hz, belongs to the low and medium frequency, so we should pay attention to the thickness of male voice, female voice should pay attention to intensity, so that low frequency is not mixed, medium frequency is not hard, high frequency is not sharp. It gives people a feeling of fullness, brightness and nature.

 

 

 

That is to say, human voice can be heard in the range of 100 Hz to 1.2 KHz. With all kinds of harmonics, the understandable pure voice only needs 200 Hz to 3.5 KHz, the upper bandwidth limit of telephone is 4 KHz, the broadcasting upper limit of TV is 8 KHz, and the bandwidth of HD teleconferencing is about 8 KHz. Therefore, in the range of language transmission, there is no need to increase the bandwidth requirement indefinitely, because the bandwidth increase will lead to transmission burden, phase interference and many other negative effects.

 

 

 

The main objectives of sound system design include "reverberation" and "sound reinforcement". This first and last part occurs in the natural environment, which will inevitably be affected by the natural environment. The flow chart shows a common small sound reinforcement system. We need to analyze the links that are prone to different quality changes before we can put forward practical design schemes and achieve excellent results.