Automatic Gain Control


Automatic Gain Control (AGC) is a recorder feature that you can activate in the General settings. Its main purpose is to keep the volume consistent throughout the recording session, especially if there are multiple sources of sound of varying intensities. For example, you record streaming audio from different radio stations using the scheduler. You don’t know in advance what volume to choose, so you choose the middle position. When you return to the recorder, you find that the recording of the loudest radio station contains clipping, and quieter broadcasts are barely audible. AGC helps avoid this by automatically reducing the volume during sharp spikes and increasing it when the sound becomes too quiet.

1 How it works

Unlike the Dynamic Compressor, the AGC function does not directly affect the recorded signal, but controls the Windows audio mixer to change the volume at the hardware level. Instead of amplifying a weak signal along with noise, we simply use the sound card amplifier. This also helps protect against clipping - a phenomenon in which the sound becomes so loud that it begins to distort.



When working with AGC, you can choose one of three modes that determine how much and how often the level will change. A small step provides smooth transitions, while a larger step allows for a faster response to sudden changes, but can lead to a less natural sound.

2 Use cases

Automatic Gain Control is especially useful in situations where you can't know the volume level of the audio source in advance. For example, when recording gameplay, you may encounter sudden changes: background music or silence is replaced by sudden explosions, gunfire, or voice messages. In such situations, AGC helps smooth out these jumps and make the recording more comfortable to listen to. The same applies to creating podcasts or videos, where it is important that all participants are heard equally well - from beginning to end, without having to manually adjust levels.

Another common situation is live broadcasts, where there is no way to process the sound after recording. In such conditions, AGC becomes an indispensable assistant, allowing you to maintain a stable volume level even if you comment on what is happening on the fly or communicate with viewers in real time. Do not consider AGC a panacea, it will only help you avoid the worst-case scenario.

However, it is worth remembering that AGC is not always appropriate. Of course, we are talking about situations when you have complete control over the situation. In this case, it is better to disable this function and entrust the final processing to a sound editor. AGC itself reduces the dynamic range of the recording, and therefore is not very suitable for recording high-quality music.

Pros

  • Automatic volume leveling.
  • Reduced risk of distortion (clipping).
  • Support for both system sound and microphone.

Cons

  • Reduces the dynamic range of recording.
  • Distorts the perception of music and special effects.

3 FAQ


Should I always use AGC?

Not necessarily. If your signal is initially stable and you plan on further processing, it is better to disable this feature. But if you are recording on the fly, for example, for a blog or stream, AGC will help you save time.

Can AGC fix bad audio?

No. AGC only adjusts volume. It does not affect noise, hissing, or poor microphone quality. It is more of an assistant than a full-fledged solution to audio problems.

Why does my audio still get distorted, even with AGC?

Because AGC reacts to changes, rather than predicting them. If there is a sudden spike, the system may react late. To minimize this effect, it is recommended to slightly reduce the input signal level before starting recording.

Does AGC work with microphone and system audio?

Yes, AGC supports both microphone and system audio. The function is activated regardless of the source, ensuring level stability in both cases.

Will AGC affect the audio quality?

No, if the settings are chosen correctly. AGC dynamically adjusts the volume, but does not degrade the quality of the original audio signal. With adequate step values, the sound remains natural and clear.

4 Summary

Automatic Gain Control in i-Sound Recorder is a handy tool that helps you achieve a stable sound level without any extra effort. It is best suited for voice recordings, where uniform volume is more important than dynamic range. However, like any automation, it has its limitations.

If you are just starting out with sound recording, feel free to turn on AGC and watch how it simplifies your task. And if you are an experienced user, use the function consciously to maintain maximum control over the final result.