IGain

iGain is an open source utility developed by Dave Lasker of Altos Design to allow Windows users to adjust the loudness of music tracks in their iTunes library to play at a more consistent volume level. It was released as freeware under the agreement.

Description
iGain functions as an interactive front-end for the MP3Gain and AACGain programs, which use the ReplayGain algorithm to compute the overall loudness of an audio track in relation to a selected playlist or series, as perceived by the human ear. It then adjusts the track's volume so that the series of tracks appear to play at a consistent volume. This overcomes any need to constantly adjust the volume of the player while the playlist or album progresses from track to track.

iTunes integration
Integration with iTunes allows iGain to:
 * Automatically locate music files in a user's media library.
 * Update playlists, albums, and tag files so that they will be resyncronized with iPods or iPhones after gain adjustments.

Backup recommendation
Users are recommended to backup their music library before performing loudness adjustments through iGain or related software. Although AACGain 1.9 offers an "undo" feature, the process is not ; files encoded in a lossy algorithm (such as AAC) will not be able to be restored to their exact bit-for-bit original state.

iTunes 3 introduced a non-destructive method of automatic volume adjustment called "Sound Check" that can also operate on AAC files protected by DRM. However, users are mixed over the effectiveness of Sound Check's algorithm compared to that of ReplayGain, used by iGain and MP3Gain.

System requirements

 * Windows 2000, XP, or later
 * iTunes 4.6 or later