Q: I have the following problem, once the final mix on my monitors the song sounds good, but when played as mp3 mix differs  player, the song is diferent to the original mix anyone can help me, thanks.

If you're hearing a lot of distortion in your mp3 mix but levels are nonetheless ridiculously low, try adjusting the output on the limiter on the master output channel of your project.  The output control knob needs to be set at -.3dB or 0.0dB (usually it's 0 by default).  Increase the limiter gain to match the peak dB on your track and the mp3 mix should sound like the project mix, except the level might be a bit lower.  I haven't figured out how to get good volume levels in the conversion with Logic yet.  I hope to discover how someday.

Also, if you're importing into iTunes to listen to your mp3, check your settings to be sure that sound check is off, equalization is off, and the "Normalize" box is NOT checked in the Logic dialogue box.