leogurl,

Highlight one of your MP3 files, right click on it, select open with MusicMatch, check always use this option.

Peerless is right about the different volume levels. You will want to equalize your files before you burn them.

MusicMatch will equalize the volumes for you. Right click in the library and select "prepare tracks for volume leveling". It may take a few minutes if you have lots of files. You only have to do this one time to each file. The next time you do it only new files will be equalized. MusicMatch will not try to do it again to a file you have already done.

Norm