Most tuners are aware of the dangers of acoustic feedback at the sound reinforcement scene, which not only seriously affects the quality of the sound reinforcement and the atmosphere, but also very likely to cause damage to the audio equipment, even in some very important Occasionally, there will be a liability accident. The sound of the sound of the whistle is usually inseparable from the following several factors: bad sound conditions, inaccurate speaker placement, unreasonable system configuration, non-standard adjustment control, inflexible response measures The The actual work, the existence of these undesirable factors will promote the whistle. After years of exploration and development, the domestic feedback on the feedback has been a lot of solutions and related products, but due to differences in sound conditions on the sound reinforcement, as well as the sound equipment and the use of different requirements, so that some audio practitioners Personnel in the specific program configuration and the use of live sound reinforcement techniques there are still some errors in the treatment method can not accurately grasp the key points, which is difficult to fundamentally eliminate the sound feedback generated.
The field control method is often encountered in practical work. For example, some small-scale conference sound reinforcement system due to funding or other reasons even without the aforementioned 31-band equalizer or digital audio equipment, this time the more practical approach is based on the actual situation of the site and equipment from the field control efforts to overcome the scene Related unfavorable factors, the systems potential to play to the best condition. So, these methods of control and the two methods mentioned above are closely related, but the use of the first two methods, the need to perform or before the meeting have more ample time to complete; now stressed that: in the field Activities have been started, how to system feedback on real-time rapid response. The most practical field control methods are usually the following:
1 sound pressure control method
In the sound reinforcement, when the scene volume to a certain extent will have a whistle, appropriate to reduce the volume feedback can be self-disappearing, to deal with this problem, we must first infer the field feedback critical maximum sound level, in operation to Not more than its fundamental principle. In the sound of the scene where the greatest feedback is: (1) damage to live sound; (2) damage to audio equipment. Therefore, if the sacrifice part of the live sound pressure level in exchange for live sound is still worth it, this point on the vocal microphone and Taiwan back to listen to the volume of the adjustment process is particularly evident. Of course, if the sound reinforcement system and the surplus power channel and speaker equipment is also very useful, through the integration of the deployment, you can increase the temporary fill point, so as to meet the needs of sound field uniformity; reasonable and balanced distribution of the sound reinforcement Of the sound pressure level, so as to avoid the sound from the microphone closer to the sound pressure caused by excessive sound feedback. It must be emphasized here that the standard for the sound pressure level of the auditorium can not be carried out in a rigid manner and it needs to be treated from the sound physiology point of view and according to the different forms of sound reinforcement. Such as in the voice conference class sound reinforcement mode should be the sound pressure level as much as possible to control at a reasonable level (70 dB ~ 80 dB), to avoid excessive promotion, this will not only help to suppress acoustic feedback, but also ease the long-term sound Under the binaural hearing fatigue.
2 real-time allocation method
In terms of volume control, there is also a concept related to sound pressure regulation, that is, if the attenuation of other secondary multi-channel microphone channel level, in exchange for the required main microphone channel volume upgrade. Vividly speaking, that is, in the case of constant system sound gain, only the available sound gain as much as possible to the most important microphone, other silent microphone channel can be as close as possible to close the state, and sometimes even in the multi-person Discuss the speech and duet in the complex case of the rapid multi-microphone will be flexible to switch to ensure the smooth progress of the meeting and the performance. Of course, this on-site tuners pre-sentence response and its ability to operate the equipment has a relatively high demand, otherwise, easily lead to the speakers words to the end of the situation, but this method is indeed in the poor expansion Acoustic environment under the more effective means of strain control.