The MP3Gain software is actually one that I am personally using all the time, when I prepare MP3 audio collection, combined from different sources. As you understand, the volume for the combined files might not be the same. They even might not be close, so you are forced to adjust volume every time, when the new audio track starts. Too much hassle… and too much headache… which might actually ruin the whole impression of the music.
The small, simple to operate, and easy to learn freeware utility will analyze the files detecting the volume level for each of them, and adjusts mp3 files, so the entire sequence will have the same volume as an average level, or the level, specifically preset by the user.
MP3Gain does not just do peak normalization, as many normalizes 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 interface is simple, but contains everything needed for successful operation. The program is very fast and extremely reliable. It never failed to perform, what I was asking from it.
Program is translated in multiple languages. 20 Languages are already included in the MP3Gain installation package.
The only limitation, I could see, is the software support for the MP3 audio format only.
The utility is highly recommended for music fans, creating their own music mp3 disks, but not only. You may find it useful, when you prepare the audio track for the slide show as well, for example.