Burning problems

I hope you can help me,I have had my computer for a year now,its the first one i have owned so i’m not exactly a techno wizard.I bought it mainly for music purposes,I also bought an mp3 mixer and decent speakers because i wanted to do my own mixes and burn them on to cd.The problem i’m having is that however i burn wavs mp3’s or just normal audio cd’s onto discs the sound quality on the bass of the music is always bad,ie I cant turn the music up loud because the bass distorts.I have tried lots of different blank cd’s,various burning software,burning at different speeds and all to no avail.As you can imagine this is very frustrating because the main reason i bought all this stuff was for music and if i cant produce decent cd’s then i’ve wasted a lot of money.I’m at a loss to explain the problem i really dont know what else to do.I’m hoping you can resolve the issue and suggest what i can do.I thought may be i should buy a new cd burner (external) but i dont know enough about them or if it would even help.I am using windows vista and have tried windows media player,express burn,real player and roxio 9 software.Thanks hope someone can help.