How to use the automatic gain controller
Audio level varies greatly among different input channels; for example certain Microphones, attached to low-priced sound cards, will result in a very low level audio signal if the user on the system is not speaking close enough to the microphone: for this purpose Active Sound Recorder comes with an embedded Automatic Gain Controller (aka AGC) which allows a good quality signal without saturating and/or cause distortions and other problems, even if the signal to be recorded varies in level.
The AGC keeps the receiver in its linear operating range by measuring the overall strength of the signal and automatically adjusting the gain of the receiver to maintain a constant level of output. When the signal is strong, the gain is reduced, and when weak, the gain is increased, or allowed to reach its normal maximum.
The AGC can be enabled/disabled through the EnableAutoGainController method: its settings can be retrieved using the GetAutoGainControllerSettings method and modified through the SetAutoGainControllerSettings.
A sample of use of the Automatic Gain Controller in Visual Basic 6 can be found inside the AutomaticGainController sample installed with the product's setup package: