This was discussed recently on the "Wish List" thread.

Equalizing the volume of your songs is a process called "Normalization". This can only be done at the beginning of the process, when the file is still in .WAV format. This option is available in most ripping software so that it happens automatically for you (provided you enable the option).

Because of they way MP3s are encoded, the only way to change the volume of an already-compressed song would be a lossy process: De-compress the MP3 to a .WAV, normalize the .WAV, then re-encode the .WAV a second time. If you re-compress something that's already been compressed once, you might induce audible artifacts. So it's not ideal. In fact, I don't know of any program that does this for you.

Usually, the only way to solve the problem properly is to re-do your collection from the original CDs, while enabling the normalization option in your ripping software. I'm in the same boat as you are: I have a lot of albums that I encoded without normalization, before I knew it was important. I'm not prepared to re-rip everything now.

My suggested solution (on the wish list board here) is to have the MP3 player software auto-adjust the volume of the next song before it begins playing it. It could do this by peeking ahead at the next song and calculating what relative volume it should be played at. This would be a very serious undertaking and it's not trivial to implement at all. The Empeg folks are pretty busy implementing more important features and fixing bugs, so it's highly unlikely we'll see this any time soon (if at all).

There is a new tag specification for MP3s (called ID3v2) that allows a "relative volume" field to be added to each file. At the moment, the Empeg can't read these kind of tags, so that's not available to us Empeg users, either.

One thing that might help is this: Very soon, the Empeg will have the ability to link a specific song to a specific EQ preset. This is on their "to do" list. You could have some EQ presets that are louder than others (by boosting more frequencies than you cut). For me, this would work perfectly, because my older albums also could use some extra EQ trimming to sound good compared to new albums. These are the same songs that need to be normalized anyway.