How to Normalize MP3 Files to Play at the Same Volume

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If you listen to MP3 files on your computer, iPod, or MP3/media player then there's a good chance that you've had to adjust the volume between tracks because of varying loudness. If a track is too loud then clipping can occur (due to overload) which distorts the sound. If a track is too quiet, you'll normally need to increase the volume; audio detail can also be lost. By using audio normalization you can adjust all your MP3 files so that they all play at the same volume.

The following tutorial will show you how to use a freeware program for the PC, called MP3Gain, to normalize your MP3 files without losing audio quality. This lossless technique (called Replay Gain) uses the ID3 metadata tag to adjust the "loudness" of the track during playback rather than resampling each file which some programs do; resampling typically decreases sound quality.

Before we begin, if you're using Windows download MP3Gain and install it now. For Mac users, there's a similar utility called, ​MacMP3Gain, which you can use. 

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Configuring MP3Gain

Use the MP3Gain settings to customize how you view files.

Luckily setup time for MP3Gain is very quick. Most of the settings are optimal for the average user and so the only change that is recommended is how the files are displayed on the screen. The default display setting shows the directory path as well as the filename which can make working with your MP3 files difficult. To configure MP3Gain to just display file names:

  1. Click the Options tab at the top of the screen
  2. Select the Filename Display menu item
  3. Click Show File Only

Now, the files that you choose will be easy to read in the main display windows.

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Adding MP3 Files

Add the MP3 files that you would like to normalize.

In order to start normalizing a batch of files, you first need to add a selection to the MP3Gain file queue. If you want to add a selection of single files:

  1. Click the Add File(s) icon and use the file browser to navigate to where your MP3 files are located.
  2. To select files to queue up, you can either select just one or use the standard Windows keyboard shortcuts (CTRL+A to select all files in a folder), (CTRL+mouse button to queue single selections), etc.
  3. Once you are happy with your selection, click the Open button to continue.

If you need to quickly add a large list of MP3 files from multiple folders on your hard disk, then click on the Add Folder icon. This will save you a lot of time navigating to each folder and highlighting all the MP3 files in them.

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Analyzing the MP3 files

MP3Gain analyzes your music to determine if it can be normalized.

There are two analysis modes in MP3Gain which are used for either single tracks, or complete albums.

  • Track Analysis: If you have queued up a selection of unrelated MP3 songs that are not part of a complete album then you can simply click the Track Analysis button. Doing this will examine each MP3 file in the list and calculate the replay gain value based on the target volume setting (default is 89 dB).
  • Album Analysis: If you're working on an album then click on the down arrow button next to the Track Analysis icon and select the Album Analysis mode. This is a better option in this scenario because all the files will be normalized based on the total album volume level. Click the Album Analysis button to begin this process.

After MP3Gain has examined all the files in the queue, it will display volume levels, calculated gain, and highlight any files in red that are too loud and have clipping.

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Normalizing Your Music Tracks

Normalize your MP3 files to even out the volume of the music.

The final step in this tutorial is to normalize the selected files and check them via playback. Just as in the previous analysis step, there are two modes for applying the normalization.

  • Track Gain: For a selection of unrelated MP3 files, Click the Track Gain icon to correct all the files in the queue; this mode is based on the target volume in track mode.
  • Album Gain: If you've got an album to correct, then click the down arrow next to the Track Gain icon and select the Album Gain menu item. This mode will normalize all the tracks in the album based on the target volume but will maintain the volume differences between each track as they were in the original album. Click the Album Gain button to begin correcting all files.

After MP3Gain has finished you will see that all the files in the list have been normalized. Finally, to do a sound check:

  1. Click the File menu tab
  2. Choose Select All Files (alternatively, you can use the keyboard shortcut CTRL+A)
  3. Right-click anywhere on the highlighted files and choose PlayMP3 File from the pop-up menu to launch your default media player

If you find that you still need to tweak the sound levels of your songs then you can repeat the tutorial using a different target volume.