What is the audio interference problem with the conference sound system?

 Looking at the routine debugging and holding of the conference system of the national organization department, the sound reduction quality has been significantly improved, but there are still some problems in some provinces and cities. The conference sound is mainly manifested as large noise, large distortion, irregular level, uneven frequency response, imbalance of sound proportion, delay of mixing and so on.

1. The noise is very big. This will affect the clarity, softness and brightness of the sound, and will cover up the sound of the venue in serious cases.

Background noise. In the case of excessive gain, automatic gain control and impedance mismatch, background noise will be generated. The conference audio microphone "flipped" out. The microphone is a link in the sound reinforcement system, and its signal quality directly affects the whole sound reinforcement effect. Therefore, it should be reasonably selected and set according to the characteristics and performance of the sound reinforcement system, the reproduction characteristics and the relative relationship between various sound sources. Sound breaking strong speakers to choose to prevent the "beat" sound of the microphone.

2. Large deformation. This is related to the nonlinear deformation of the equipment and human factors. Symptoms are hoarse, broken, sharp and harsh. Severe can affect the clarity, softness, brightness, fullness and perception of the scene. There are many reasons for distortion, such as high sensitivity of the microphone, improper placement, abnormal power supply of the phantom power supply, excessive level adjustment of the mixer, improper adjustment of the equalizer, and impedance mismatch between devices.

3. The level is not standardized. No equipment such as mixer or equalizer was debugged before adjustment, resulting in too high or too low signal level.

4. The frequency response is not uniform. This is related to frequency response indicators and human factors, such as microphone pointing deviation, excessive medium frequency attenuation, and long microphone transmission lines. It will affect the clarity, layering and fullness of sound reduction.

5. Disproportionate. If the proportion of the main control room, the main venue and the sub-venue is out of balance, it will affect the recovery of the long-distance balance of other sub-venues, resulting in the decline of the overall effect of the meeting.

6. The reverb delay is incorrect. Due to the different requirements of various conference types and audio environments on the reverberation delay time, it is necessary to adjust the reverberation delay parameters according to the acoustic characteristics.

(1) The size of the sound field affects the sense of time and auditory time of sound reflection during reverberation.

(2) reverberation time is the process of spreading from the sound source to the surrounding absorption and reflection. The reverberation time depends on the size of the venue. The greater the distance, the longer the reverberation time. Conference sound audio processing equipment compensates and modifies some sound defects, but improper adjustments may be counterproductive. If the reverberation time is too long, the sound will have a "turbid" feeling. It is necessary to combine the actual situation and add a reasonable reverberation effect to enhance the depth of the sound.

(3) Sound diffusion is a parameter that reflects the acoustic characteristics of the site. The microphone should be set up reasonably to make up for the defects of the acoustic diffusion conditions of the conference in the venue, and avoid the vibration echo area and strong reflection direction.