MP3Gain: Free Sound Amplifier
When mixing CDs, the only issue I always faced was to adjust the volume of different music tracks I’m going to mix. A few Google searches got me to this wonderful freeware that makes normalizing sound of audio files a piece of cake!
MP3Gain automatically analyzes and adjusts MP3 files so that they have the same volume level. This freeware made my life easy and it’s only takes a few seconds to increase or decrease the loudness.
MP3Gain does not just do peak normalization, as many normalizers do. Instead, it does some statistical analysis to determine how loud the file actually sounds to the human ear. Also, the changes MP3Gain makes are completely lossless. There is no quality lost in the change because the program adjusts the mp3 file directly, without decoding and re-encoding.
The text quoted above from the official site says it all. To use, all you have to do is drag and drop MP3 files in the MP3Gain window, set Target Volume and and press the Track Gain button. Simple, eh?
This freeware works on Windows (XP, Vista and 7).