Audio normalization
Encyclopedia
Audio normalization is the application of a constant amount of gain to an audio recording in order to bring the average or peak amplitude to a target level (the norm).
Because the same amount of gain is applied across the given range, the signal-to-noise ratio and relative dynamics are generally unchanged. Normalization differs from dynamic range compression, which applies varying levels of gain over a recording to fit the level within a minimum and maximum range.
Normalization is commonly amongst the functions provided by a digital audio workstation
.
sample value or analog signal peak to a given level.
Since it only searches for the highest level, it does not account for the apparent loudness
of the content. As such, peak normalization is generally used to change the volume in such a way to ensure optimal use of the distribution medium in the mastering stage of a recording.
value, or it can be a measure of human-perceived loudness, such as that offered by ReplayGain and EBU R128.
Depending on the dynamic range of the content and the target level, loudness normalization can result in peaks that exceed the recording medium's limits. Software offering such normalization typically provides the option of using dynamic range compression to prevent clipping when this happens. In this situation, signal-to-noise ratio
and relative dynamics are altered.
Because the same amount of gain is applied across the given range, the signal-to-noise ratio and relative dynamics are generally unchanged. Normalization differs from dynamic range compression, which applies varying levels of gain over a recording to fit the level within a minimum and maximum range.
Normalization is commonly amongst the functions provided by a digital audio workstation
Digital audio workstation
A digital audio workstation is an electronic system designed solely or primarily for recording, editing and playing back digital audio. DAWs were originally tape-less, microprocessor-based systems such as the Synclavier and Fairlight CMI...
.
Peak normalization
One type of normalization is peak normalization, wherein the gain is changed in order to bring the highest PCMPulse-code modulation
Pulse-code modulation is a method used to digitally represent sampled analog signals. It is the standard form for digital audio in computers and various Blu-ray, Compact Disc and DVD formats, as well as other uses such as digital telephone systems...
sample value or analog signal peak to a given level.
Since it only searches for the highest level, it does not account for the apparent loudness
Loudness
Loudness is the quality of a sound that is primarily a psychological correlate of physical strength . More formally, it is defined as "that attribute of auditory sensation in terms of which sounds can be ordered on a scale extending from quiet to loud."Loudness, a subjective measure, is often...
of the content. As such, peak normalization is generally used to change the volume in such a way to ensure optimal use of the distribution medium in the mastering stage of a recording.
Loudness normalization
Another type of normalization is based on a measure of loudness, wherein the gain is changed in order to bring the average amplitude to a target level. This average can be a simple measurement of average power, such as the RMSRoot mean square
In mathematics, the root mean square , also known as the quadratic mean, is a statistical measure of the magnitude of a varying quantity. It is especially useful when variates are positive and negative, e.g., sinusoids...
value, or it can be a measure of human-perceived loudness, such as that offered by ReplayGain and EBU R128.
Depending on the dynamic range of the content and the target level, loudness normalization can result in peaks that exceed the recording medium's limits. Software offering such normalization typically provides the option of using dynamic range compression to prevent clipping when this happens. In this situation, signal-to-noise ratio
Signal-to-noise ratio
Signal-to-noise ratio is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. It is defined as the ratio of signal power to the noise power. A ratio higher than 1:1 indicates more signal than noise...
and relative dynamics are altered.