随机临界频点识别与声反馈智能处理系统

Stochastic critical frequency recognition and an acoustical feedback intelligence processing system

室内扩音中,由于拾音器的布点位置不同,其声场环境更加复杂,具体表现在声反馈条件下,多点声反馈产生。其特点是相互交叉反射波,在不同拾音点形成声波的复杂、时变、多向、随机及非线性。这破坏了扩声系统的稳定和应有的增益,对于该难题,提出用随机阻带识别技术来处理和替代过去的子带识别处理方法。以全通滤波器为主通道,运用随机阻带识别技术,在对随机临界频点识别的同时,自动生成反向抑制波(阻带)。在保证原扩声系统增益前提下,解决因声反馈带来的啸叫频点的不稳定性,确保室内扩声系统的稳定性。实验在扩音系统中加入以随机阻带识别技术的声反馈智能处理系统,得出两者之间扩声增益的对照,从而证实该声反馈智能处理系统不仅功效显著,而且又快又好地解决了远距离拾音布点容易降低扩声增益的难题。

In the room public address system,the acoustic pickup stationing position is different,the sound field environment becomes more complex.This is because under acoustical feedback condition the multi-spot acoustic feedback produces intercross reflected waves to form a time-variable,multi-directional,stochastic and non-linear acoustic field at different electric pickup spots.This damages the gain and stability of the amplifying system.Regarding this difficult problem,the stochastic stop-band recognition technology is proposed to substitute the past processing method.With this method the entire filter is taken as a primarily channel,the stochastic stop-band recognition technology is used to recognize the stochastic critical frequency and meantime automatically to produce the reverse suppression wave（stop-band）.Thus the frequency instability problem caused by the acoustical feedback can be solved under the premise of keeping the original gain of amplifying system.The experiment and comparison has been done by adding the acoustical feedback intelligence processing system with the stochastic stop-band recognition technology into the public address system.Results confirm that the effect of the acoustical feedback intelligence processing system is remarkable,and the long-distance stationing of electric pickups can be easily carried out without reducing the gain of amplifying system.