Effects Preferences allow customizing audio effects, applied to encoded audio. Volume adjusting, Fade-in, and Fade-out, Trimming of silence and Limiting of duration can be managed in Effects Preferences tab.

To open Effects Preferences tab, choose Converter > Preferences > Effects.

Loudness (EBU R128) Normalization

Loudness (R128) Normalization is useful when you need to equalize Perceived Loudness of all files if your audio collection to the same Target Level. 

Loudness Volume Normalization in To MP3 Converter for Mac

Check "Adjust volume ..." option to adjust the volume of converted audio with peak or Loudness Normalization.

Click on "Peak" button to change Normalization Method to "Loudness" if it is not selected yet.

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Target Level of Loudness Normalization

Target level of loudness normalization

Press "...LUFS" button to select target level of Loudness Normalization, expressed in LUFS (Loudness Units relative to Full Scale). Please note that too high Target Level can result in peaks that exceed the audio format limits. Dynamic range compression is applied in such cases to prevent clipping. In normal circumstances, the recommended value for Target Level should be between -23 LUFS and -10 LUFS.

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Peak Normalization

With Peak normalization, the gain is changed to bring the highest signal peak to a target level. Peak normalization is used to adjust the volume to ensure optimal use of the audio format in the mastering stage of a recording.

To normalize the volume of converted files using Peak method check "Adjust volume ..." option in Effects tab and choose "Peak" in the dialogue window if it is not selected yet. To open the dialogue window, click on "Loudness" button.

 Peak volume normalization in To MP3 Converter for Mac OS X

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Target Level of Peak Normalization

Press "...dBFS" button to select Target Level of normalization, expressed in dBFS (Decibels relative to Full Scale). 0.0 dBFS is assigned to the maximum possible digital level.

Target level of peak volume normalization

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Automatic Volume Control

Check "Enable automatic volume control" option to increase the level of too quiet parts of audio files.

Automatic Volume Control is an excellent addition to normalization of audio with too loud and too soft parts, peaks and clicks, including podcasts, interviews, and voice recordings.

 Automatic Volume Control with Peak Normalization

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Fade-in and Fade-out

Check "Fade in ..." option to make the volume of converted audio gradually increased from silence at the beginning.

Check "Fade out ..." option to make the volume of converted audio gradually decreased to silence at the end.

Click on seconds button to change the length of Fade In or Fade Out effect.

Fade-in and Fade-out effects in To MP3 Converter for Mac

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Trim Silence

Check "Trim Silence ..." option to trim silence at the start and the end of the converted audio. We recommend using Trim Silence option together with volume adjusting or normalization. Otherwise, quiet audio of low level can be unexpectedly truncated.

Click on "...dBFS" button to change the Silence Threshold. Audio below this level will be considered as silence.

Trim silence using To MP3 Converter for Mac OS X

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Limit Duration

Check "Limit duration ..." option to limit the length of converted audio. We recommend using "Limit Duration" option to quickly check if conversion results are as expected.

Click on seconds button to change the maximum duration of converted audio.

Limit duration of audio files in To MP3 Converter for Mac OS X