Make quiet MP3 files louder with Audacity

There are many ways to make quiet MP3 files louder ("Normalize"), but the easiest is by far using Audacity, since you can process multiple files at once (also known as batch processing) with the Macro tool:

• Click Tools > Macros... > MP3 Conversion > Files
• Navigate to the folder with the MP3 files you want to convert, select them all, and click Open

The normalized files will be created in a folder called "macro-output".

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