噪声大。它影响声音的清晰度柔和度和明亮度，严重时会掩盖了会场的声音。
Loud noise. It affects the clarity, softness and brightness of the sound. In serious cases, it will cover up the sound of the venue.
① 本底噪声。由于增益过大采用自动增益控制方式阻抗不匹配等，都会出现本底噪声。
① Background noise. Because the gain is too large, using automatic gain control mode, impedance mismatch, etc., background noise will appear.
② 麦克风“扑”声。麦克风是扩音系统的*个环节，其信号质量的好坏直接影响到整个会议效果，因此要根据其特点和性能声源重现的特征以及各声源之间的相对关系合理选择和设置。对于破音较强的发言者，应选用防“扑”声的麦克风。
② Microphone "flutter" sound. Microphone is a link of the public address system, and its signal quality directly affects the effect of the whole conference. Therefore, it should be reasonably selected and set according to its characteristics and performance, the reproduction characteristics of sound sources and the relative relationship between sound sources. For speakers with strong breaking sound, anti "flutter" microphone should be selected.
失真大。它与设备的非线性失真和人为因素有关。其特征是声音嘶哑破损尖细刺耳，严重时会影响声音的清晰度柔和度明亮度丰满度和现场感。引起失真的原因是多方面的，如麦克风的灵敏度过高摆放位置不合适具有幻像电源的麦克风供电不正常调音台的电平调整过大均衡器的调整不适当设备之间的阻抗不匹配等。
Large distortion. It is related to the nonlinear distortion of equipment and human factors. It is characterized by hoarseness, damage, sharp and harsh sound. In serious cases, it will affect the clarity, softness, brightness, fullness and sense of scene of the sound. There are many reasons for distortion, such as the sensitivity of the microphone is too high, the placement position is inappropriate, the power supply of the microphone with phantom power supply is abnormal, the level adjustment of the mixer is too large, the adjustment of the equalizer is inappropriate, the impedance mismatch between devices, etc.
电平不规范。在调试之前没有对调音台均衡器等设备进行调校，造成信号电平过高或过低。另外，将不平衡的线路输出与平衡的线路输入直接连接，造成信号电平下降。
The level is not standard. Before commissioning, equipment such as mixer and equalizer were not adjusted, resulting in high or low signal level. In addition, the unbalanced line output is directly connected with the balanced line input, resulting in the decrease of signal level.
频响不均匀。它与设备的频响指标和人为因素有关，如麦克风的指向偏离声源中频和低频衰减太多麦克风传输线过长等，都将影响声音还原的清晰度层次感丰满度。
Uneven frequency response. It is related to the frequency response index of the equipment and human factors, such as the direction of the microphone deviates from the medium frequency and low frequency attenuation of the sound source too much, and the microphone transmission line is too long, which will affect the clarity, hierarchy and fullness of sound restoration.
声音比例失调。如果总控室主会场发言的分会场叁者之间的声音比例失调，就会影响其他分会场还原远程声音的平衡度，造成会议的整体效果下降。
The sound is out of proportion. If the voice proportion of the branch venue where the main venue of the general control room speaks is out of proportion, it will affect the balance of restoring the remote voice of other branch venues, resulting in the decline of the overall effect of the meeting.
混响延时不当。不同的会议类型和拾音环境对混响和延时的要求不同，因此要根据声学特性，调整混响和延时的参数。
Improper reverberation delay. Different conference types and pickup environments have different requirements for reverberation and delay. Therefore, the parameters of reverberation and delay should be adjusted according to the acoustic characteristics.
① 会场的大小影响声场混响中反射的时间和听觉上的时间感。
① The size of the venue affects the reflection time and auditory sense of time in the sound field reverberation.
② 混响时间反映声音从声源扩散经周围吸收和反射的过程，混响时间视会场的大小而定，空间越大，混响时间也越大。要通过音频处理设备弥补和修饰某些声音的缺陷，但调整不当，就会适得其反。若混响时间过长，声音就有“浑浊”感，因此要结合实际，合理加入混响效果，以增强声音的纵深感。延时处理也是如此。
② The reverberation time reflects 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 space, the greater the reverberation time. It is necessary to make up for and modify the defects of some sounds through audio processing equipment, but improper adjustment will be counterproductive. If the reverberation time is too long, the sound will have a sense of "turbidity". Therefore, the reverberation effect should be reasonably added in combination with the reality to enhance the depth of the sound. The same is true for delay processing.
③ 混响的频率特性反映在不同频率下声音的混响效果和音质。要熟悉混响的频率特性，调整好麦克风拾取**声与反射声的比例，增加声音的真实感和清晰度。
③ 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 proportion of * * sound and reflected sound picked up by the microphone, and increase the realism and clarity of the sound.
④ 声扩散是反映会场声学特性的参数，要合理设置麦克风，弥补会场声扩散条件的缺陷，同时要避开具有颤动回声区域和强反射的方向。
④ Sound diffusion is a parameter reflecting the acoustic characteristics of the venue. Microphones should be set reasonably to make up for the defects of sound diffusion conditions in the venue. At the same time, areas with vibrating echo and directions with strong reflection should be avoided.
常见干扰
Common interference
音频信号在传输过程中产生的干扰是多方面的，常见的有电源干扰设备之间干扰灯光干扰等。
The interference of audio signal in the transmission process is multifaceted, including power interference, interference between equipment, light interference and so on.
电源干扰。
Power interference.
电源接地不良设备之间的地线接触不良和阻抗不匹配设备的电源未经&濒诲辩耻辞;净化&谤诲辩耻辞;处理音频线与交流电线同管同沟或同桥架铺设，都会对音频信号产生杂波干扰，形成低频的交流&濒诲辩耻辞;嗡嗡&谤诲辩耻辞;声。
Poor power grounding, poor ground wire contact and impedance mismatch between equipment, the power supply of equipment is not "purified", and the audio line and AC line are laid in the same pipe, ditch or bridge, which will produce clutter interference to the audio signal and form low-frequency AC "buzzing" sound.
设备之间干扰。
Interference between devices.
&濒诲辩耻辞;啸叫&谤诲辩耻辞;是扬声器与麦克风之间发生正反馈引起的，其主要原因是麦克风离扬声器过近或麦克风指向扬声器。&濒诲辩耻辞;空声&谤诲辩耻辞;是由声波延时产生的，若麦克风既拾取声源信号又拾取经扩音还原的信号，或者与声源距离不同的两只麦克风拾取同一声源的信号，或者一只麦克风拾取经扩音还原后的另一只麦克风的信号，都将产生相应的路程差而造成延时。当这些信号迭加后，某些频率成份相互抵消，形成了&濒诲辩耻辞;空声&谤诲辩耻辞;。
"Howling" is caused by positive feedback between the speaker and the microphone. The main reason is that the microphone is too close to the speaker or the microphone points to the speaker. "Empty sound" is generated by sound wave delay. If the microphone picks up both the sound source signal and the amplified and restored signal, or two microphones with different distance from the sound source pick up the signal of the same sound source, or one microphone picks up the signal of the other microphone after amplified and restored, it will produce corresponding distance difference and cause delay. When these signals are superimposed, some frequency components cancel each other to form "empty sound".
灯光干扰。
Light interference.
会场若采用镇流器方式间歇启动的照明灯，灯管激发时将产生高频辐射，并通过麦克风及其引线串入，出现&濒诲辩耻辞;哒哒&谤诲辩耻辞;声;麦克风线离灯线太近，也会出现&濒诲辩耻辞;吱吱&谤诲辩耻辞;声;另外，外界的高频电磁也会产生干扰。
If the lighting lamp is intermittently started by ballast in the venue, high-frequency radiation will be generated when the lamp tube is excited, and it will be connected in series through the microphone and its lead, resulting in a "clatter" sound; If the microphone line is too close to the light line, there will also be a "squeak" sound; In addition, external high-frequency electromagnetic interference will also occur.
会议系统音频干扰处理方法
Audio interference processing method of conference system
视频会议的声音还原，应根据声学的理论知识，按照不同的实际情况，灵活调整调音台和均衡器，对声音进行加工和美化，弥补声场的缺陷，营造较为理想的声学环境;适当调整压缩限幅器，遇到突发性的大峰值信号不过载和不失真，同时又要避免压缩限幅器长时间处于压缩状态，使声音衔接平滑圆润。
The sound restoration of video conference should flexibly adjust the mixer and equalizer according to the theoretical knowledge of acoustics and different actual conditions, process and beautify the sound, make up for the defects of sound field and create an ideal acoustic environment; Properly adjust the compression limiter to avoid overload and distortion in case of sudden large peak signal. At the same time, avoid the compression limiter in the compression state for a long time, so as to make the sound connection smooth and round.
