squier v.m. jazz high action problem.

Hi.I have a V.M. squier jazz and i had lowering the action because it was pretty high.I have set it now about 2.0-2.5mm between the top of the 17 fret and the bottom of the string.

Now the bass is playable but the sound is not good as before.

I have the bass for 2 weeks and play everyday a couple of hours or more.Do you think i need new strings already?
It is my first bass, i dont know a lot about basses.

thanks

bobb
athens