Audio System Value from Potential Acoustic Gain

Writer / VP Office

Have you ever faced the problem that the same microphone perform differently on two different sound system? You can hear the feedback easily in one system, but it doesn’t happen in the other system even the sound quality. What exactly the factor to influence and cause the effect? As an electro-acoustic system, customer wouldn’t buy it if the volume isn’t loud enough, and if there is feedback when using it. Thus, we need to know a physical concept and figure out how to check it.

There is an indicator called Potential Acoustic Gain (PAG) or Gain Before Feedback (GBF). In China, sound transmission gain means the result of threshold limit value of feedback sound minus the audio source and minus 6dB. These indicators are trying to describe the ability audio gain before feedback in the eletro-acoustic system including microphone.

Why we are going to discuss this issue: Many audiovisual engineering vendors face this problem that they would pick up the amplification equipment they choose to construct a conference system, but they can’t increase the volume or they will heard the feedback sound. Is it possible there are something wrong with the equipment? Do we have a standard which we can base on?