What is the problem of audio interference in conference sound systems
The quality of sound restoration has been significantly improved, but there are still some problems in individual provinces and cities, mainly for loud noise, distortion, irregular level, uneven frequency response, sound proportion imbalance, mixing delay and so on.
1. Loud noise. This will affect the clarity, softness and brightness of the sound, and in severe cases will mask the sound of the venue.
① Background noise. When the gain is too large, automatic gain control is used, impedance mismatch, etc., background noise will be generated.
② The microphone "flutter" sound. The microphone is the first link in the PA system, and its signal quality directly affects the whole PA effect, so it should be reasonably selected and set according to the characteristics and performance of the PA system, reproduction characteristics and the relative relationship between the sound sources. For speakers with strong broken sound, a microphone should be used to prevent "flapping" sound.
2, large deformation. This is related to the nonlinear deformation of the equipment and human factors. Symptoms are hoarse, broken, shrill, severe can affect the clarity of the sound, smoothness, brightness, fullness and sense of scene. There are many reasons for the distortion, such as excessive microphone sensitivity, improper placement, abnormal phantom power supply, excessive level adjustment of the mixer, improper adjustment of the equalizer, impedance mismatch between devices, etc.
3, the level is not standardized. Devices such as the console and equalizer are not debugged before tuning, resulting in high or low signal levels. In addition, the direct connection of unbalanced output and balanced line input causes the signal level to drop.
4, uneven frequency response. This is related to frequency response indicators and human factors, such as microphone pointing offset, IF attenuation is too large, microphone transmission line is too long, etc., will affect the clarity, layer sense, fullness of sound reduction.
5. Voice imbalance. If the sound ratio is out of whack in the main control room, main venue and sub-venue, it will affect the restoration of remote sound balance in other sub-venues, resulting in a decline in the overall effect of the conference.
6. Reverberation delay is incorrect. Due to the different requirements of reverberation delay time for different meeting types and audio environments, the reverberation delay parameters should be adjusted according to the acoustic characteristics.
① The size of the field affects the time sense of sound reflection and auditory time sense during reverberation.
② Reverberation time is the process of sound diffusion from the sound source through the surrounding absorption and reflection, the reverberation time depends on the size of the venue, the larger the distance, the longer the reverberation time. Audio processing equipment compensates and modifies certain sound defects, but improper adjustments can backfire. If the reverberation time is too long, the sound will produce a sense of "turbidity", so it is necessary to combine the actual situation and reasonably add the reverberation effect to enhance the depth of the sound. Deferred processing also applies.
The frequency characteristics of reverberation reflect the reverberation effect and sound quality of sound at different frequencies. Be familiar with the frequency characteristics of reverberation, adjust the ratio of the microphone to the direct sound and the reflected sound, and improve the realism and clarity of the sound.
Sound diffusion is a parameter that reflects the acoustic characteristics of the site. The microphone should be set reasonably to make up for the defects in the sound diffusion conditions of the venue, and the vibration echo area and strong reflection direction should be avoided.