人们在轻松愉快地观看文艺演出时可曾想到,音响工作者为使观众获得满意的音质效果不仅事先在厅堂中合理地布置了扩声系统,而且在演出的整个过程中他们始终在音响控制台前紧张地工作着。人们不仅要问,为什么在演出时需要有一套扩声系统伴随着工作呢?下面就谈谈午台扩声系统的一些情况。一、午台扩声系统的作用一个声源(例如演员或乐器)在发声时都具有一定的初始能量,叫做声能。它经过空气媒介的传递在到达接收点(如传声器膜片或观众的耳膜)时,由于空气分子的相互碰撞,声能密度便有所减小,能量有所降低。这样,在接收点所收到的声强要比声源发出时为小。在一个周围无反射的声场条件(声学上称为自由场一例如消声室)中,这种声能的衰减是与接收点离声源的距离成比例的,即p∞1/r,距离r每增加一倍,声强 When people look at a theatrical performance easily and pleasantly, it can be thought of that the acoustics workers not only arranged the sound reinforcement system in the hall in advance in order to obtain the satisfying sound quality of the audience, but also always performed the audio control console Working nervously before. People not only have to ask why a sound reinforcement system needs to be accompanied by work during the performance. Here are some situations about the PA system. First, the afternoon sound reinforcement system role A sound source (such as actors or musical instruments) have a certain initial sound in the sound, called the sound energy. When it reaches the receiving point (such as the microphone diaphragm or the audience’s eardrum) through the transmission of the air medium, the acoustic energy density is reduced and the energy is reduced due to the collision of air molecules. In this way, the sound intensity received at the receiving point is smaller than when the sound source is emitted. In a non-reflective ambient sound field condition (acoustically termed a free field such as an anechoic chamber), this attenuation of sound energy is proportional to the distance of the receiving point from the sound source, ie, p∞1 / r, Each doubling of r, sound intensity