Enlarge sound system is to put the weak current signal treatment of peripheral equipment such as mixer, and then through the audio power amplifier amplification, again sent to the speakers sound process, therefore, a faint noise in front of the speaker and covered by ac signal amplifier, power amplifier noise made by the speaker and hum again, So in front of the loudspeaker each device must have a very high sound to noise ratio to ensure that the whole system without noise and hum interference;
At present, there are several possible reasons for the severe hum noise in this system:
A: The microphone, the microphone cable and the microphone signal processor have hum sound;
B: Mixer, feedback suppressor, equalizer and other equipment have their own hum sound;
C: Power amplifiers have their own hum.
In order to suppress AC noise interference, the following methods can be used to solve the problem:
1. replace the former equipment;
2. Reasonable adjustment of line installation and loudspeaker;
3. Use clean power supply. Can use an independent group of power supply, separate power supply with air conditioning, lighting and other equipment; Or the use of isolating power transformers, these are effective measures