What kind of monitors did you use when recording and playback?
If your monitors are not flat responce, then the're not giving you the true sound; there adding there on bass boost and stuff. so when you play it on any boom box or stereo, it will sound different. Here's what i do. On my stereo, i hardy every turn the volume past 10 because when i listen to pro cds, there really loud at that volume setting. so i think "If i can't here my cds at that volume then i'm doing something wrong." So what i did was, i turned the volume on my studio monitors up to where they was as loud as the stereo volume. Then i would try my best to get the loudest volume possible, without distorting, at that level. then, when i play the cd at home, it's sounds good. you can also use a limiter to keep the volume under control. and if you've got to volume wide-open and it's still not loud enough, use a compresser to pump it up.
good luck.
zeke