help volumes are all off when put on disc or mp3 player

I have mixed all of my bands songs through audacity, when i burn them to a disc the volume from song to song is different. The first song the volume is one level the next song the level is way lower ect…, How do i make my songs consistantly the same volume for the cd? Seems like a really dumb question but i can not figure this out. please help!

I’ve replied to your duplicate post: http://audacityteam.org/forum/viewtopic.php?f=16&t=7588