Replay Gain How does it work?

I went through my entire mp3 collection and set the gain for all songs at 89db as suggested in the program. I then loaded some of the albums into my sandisk clip+. I have the replay gain mode set to “song” and the level set at 7db. No matter what db setting I use I don’t appear to hear any audible difference in the sound output level. Can someone explain to me how this works and if I can boost the volume level of songs by using this feature?

See this post from the Fuze forum

If you restart the song after changing the setting you should hear a change.

I can hear the change while the song is playing. I would think that if you don’t hear a change then either you didn’t record the track with the volume analyzed or the analysis was pretty close to zero.

When replay gain is turned on, does the music sound a little muddy to you? Afer a few A/B comparisons I just turned it off. I wouldn’t have expected any loss of fidelity so I’m thinking it is just my ears.