Normalize

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• Ed 10Jun11 proofed & all links verified intact

Use the Normalize effect to set the maximum amplitude of single or multiple tracks, equalize the peak volumes of the left and right channels of stereo tracks and optionally remove any DC offset from the tracks.

Accessed by: Effect > Normalize...

Remove any DC offset

When this box is checked Normalize will attempt to remove any DC offset in the selection by finding the average of all the sample values in the selection, then subtracting that average value from all the samples.

Bill 10Jun11: ToDo-2 I'm not sure the following is true. I have not been able to create an asymmetrical waveform where DC offset removal fails.

This works well on long selections containing a mix of sounds, but may actually create DC offset when applied to short sections of recordings of voices or certain instruments that have an inherently asymmetrical waveform.

Normalize Maximum Amplitude to

Enter the value for the maximum amplitude you would like the processed selection to have. Normalize defaults to 0.0 dB, which is the maximum amplitude possible without clipping. Enter a negative value if you want the maximum amplitude to be less the maximum possible without clipping. If you enter a positive value, clipping will occur.

Normalize stereo channels independently

When this box is unchecked (the default) Normalize will work on the channels of a stereo track as a pair and change the level of both channels by the same amount. Use this if your recording is inherently balanced as this mode will preserve the original stereo balance of your recording.

When this box is checked Normalize will work independently on left and right channels of a stereo track. This is useful for correcting stereo recordings of LPs and cassettes which may be unbalanced, as long as significant clicks are removed first.

Tips

Normalizing multiple audio tracks
If you select multiple tracks and apply the Normalize effect, then all audio tracks will be independently normalised to the same peak level.

For example, if you set "Normalize Maximum Amplitude to:" 0.0 dB, every selected audio track will be normalized to 0.0 dB, irrespective of its original level. Whatever peak volume differences there were between the tracks will be removed.

Difference from the Amplify effect
With Amplify, if you select multiple tracks and apply the effect, then all audio tracks will be amplified by the same amount thus preserving the balance between the tracks.

Normalize offers the option to remove DC offset, Amplify does not offer that option.

For a more thorough discussion of differences between the Amplify and Normalize effects, see this page in the Audacity wiki