By definition, album gain is not going to make all tracks as loud as possible the quieter tracks are going to remain that much quieter than the louder tracks, and they’ll average out to 89. If you’re using album gain, tracks will be played at 89 dB plus or minus a few dB, depending on how much louder or quieter each track is relative to the other tracks on the album. If you’re using track gain, every song is played at 89 dB no song is any louder than any other. This avoids the common problem of having to manually adjust volume levels between tracks when playing audio files from albums that have been mastered at different loudness levels. ReplayGain … allows players to normalize loudness for individual tracks or albums.
ReplayGain is … a technique invented to achieve the same perceived playback loudness of audio files.
