An audio compressor is a device or software that reduces the dynamic range of an audio signal. In other words, it reduces the volume of the loudest parts of the signal and amplifies the quieter parts, making the overall signal more even in terms of volume.
There are several controls on a compressor that allow you to shape the way it affects the signal:
- Threshold: This is the level at which the compressor begins to take effect. Anything below the threshold is unaffected, while anything above it is compressed.
- Ratio: This determines how much the compressor reduces the volume of the signal above the threshold. A ratio of 4:1 means that for every 4 dB the signal is above the threshold, the compressor reduces the volume by 1 dB.
- Attack time: This is the amount of time it takes for the compressor to start reducing the volume of the signal after it crosses the threshold. A fast attack time means that the compressor will start reducing the volume almost immediately, while a slow attack time gives the signal more time before the compressor kicks in.
- Release time: This is the amount of time it takes for the compressor to stop reducing the volume of the signal after it falls below the threshold. A fast release time means that the compressor will stop compressing the signal quickly, while a slow release time allows the compressor to continue reducing the volume for a longer period of time.
- Make-up gain: This control allows you to increase the overall volume of the signal after it has been compressed. This is useful because compressing a signal usually reduces its overall volume, so the make-up gain allows you to bring it back up to the desired level.
To use a compressor, you would adjust the controls to shape the way it affects the signal. For example, you might set a high threshold and a low ratio to only compress the very loudest parts of the signal, or a low threshold and a high ratio to heavily compress the entire signal. The attack and release times can be adjusted to smooth out the transitions between the compressed and uncompressed sections of the signal.
I hope this helps! Let me know if you have any questions or need further clarification on any of the concepts I've explained.