Loudness Normalization and Dynamic Range Control

Loudness normalization aims to ensure that different audio sources, such as songs, commercials, and movies, have similar perceived loudness levels when played back on the same device.

RMS normalization is a method of loudness normalization that measures the average power of an audio signal over a specified time interval and adjusts the gain accordingly to achieve a target loudness level.

Peak limiting only affects the highest peaks in an audio signal, reducing their amplitude to a specified threshold, while true peak limiting analyzes the entire signal and adjusts the gain to prevent inter-sample peaks from exceeding a specified threshold.

Dynamic range control aims to reduce the difference between the loudest and softest parts of an audio signal, making it more consistent and easier to listen to in different environments.

Compression and limiting are the two main types of dynamic range control. Compression reduces the dynamic range of an audio signal by attenuating the loudest parts, while limiting prevents the signal from exceeding a specified threshold.

Compression reduces the dynamic range of an audio signal by attenuating the loudest parts, while limiting prevents the signal from exceeding a specified threshold. Compression is typically used to make an audio signal more consistent and easier to listen to, while limiting is used to prevent distortion and ensure that the signal does not exceed the maximum level.

The attack time of a compressor determines how quickly the compressor responds to changes in the audio signal. A shorter attack time will cause the compressor to respond more quickly to transients, while a longer attack time will cause the compressor to respond more slowly.

The release time of a compressor determines how quickly the compressor stops applying gain reduction after the signal level drops below the threshold. A shorter release time will cause the compressor to stop applying gain reduction more quickly, while a longer release time will cause the compressor to stop applying gain reduction more slowly.

The ratio of a compressor determines the amount of gain reduction applied to the audio signal. A ratio of 2:1 means that for every 2 dB increase in the input signal level, the output signal level will increase by 1 dB. A ratio of 4:1 means that for every 4 dB increase in the input signal level, the output signal level will increase by 1 dB, and so on.

The threshold of a compressor determines the level at which the compressor starts to apply gain reduction. Signals below the threshold will not be affected by the compressor, while signals above the threshold will be attenuated by the amount specified by the ratio.

The threshold of a limiter determines the level at which the limiter starts to apply gain reduction. Signals below the threshold will not be affected by the limiter, while signals above the threshold will be attenuated to the level of the threshold.

The attack time of a limiter determines how quickly the limiter responds to changes in the audio signal. A shorter attack time will cause the limiter to respond more quickly to transients, while a longer attack time will cause the limiter to respond more slowly.

The release time of a limiter determines how quickly the limiter stops applying gain reduction after the signal level drops below the threshold. A shorter release time will cause the limiter to stop applying gain reduction more quickly, while a longer release time will cause the limiter to stop applying gain reduction more slowly.

A compressor reduces the dynamic range of an audio signal by attenuating the loudest parts, while an expander increases the dynamic range by amplifying the softest parts. Compressors are typically used to make an audio signal more consistent and easier to listen to, while expanders are used to create a more dramatic and dynamic sound.

A gate is an audio effect that reduces the amount of noise in an audio signal by muting the signal when it falls below a specified threshold. Gates are often used to reduce the amount of background noise in a recording or to prevent feedback in a live sound system.