After playing many Ibanez basses "thin sounding" is the feeling I get from the SR series. I think they are pretty good for slap but I don't like their tone for heavy finger style, I much prefer the bulk of the BTB line (I have 2).
You can try changing the pick ups and/or pre amp section but if the natural sound of the bass is thin then that is what it will pretty much be.
You can try changing the pick ups and/or pre amp section but if the natural sound of the bass is thin then that is what it will pretty much be.