I've been having problems with the balance of volume between strings on my bass. I have a Toby Pro 6, and the lowest strings get a lot of low end and are easily heard. However, when I go to play on the C, I have to pluck harder to get the same volume, and in turn, the tone suffers. If I adjust the height of the pickups, would this be corrected, or is there something else I have to do? Thanks in advance.