Without actually hearing what you're hearing it's hard to know where the unwanted noise is coming from; assuming you know what you're doing regarding setting up a bass and it isn't fret buzz and also that you're being sensible with the EQ then it might be you have steel round wound strings on the bass which usually do start out bright - however after 6 months use I'd have expected these to have mellowed somewhat and lost their initial brightness. Having said all that, and if you don't want flats and the Elixirs [i]are[/i] indeed steel then I'd suggest you try some nickel round wounds which usually have a warmer tone and will probably feel smoother for fingerstyle.