Another (easier) thing you can do is adjust the polepieces on the humbucker - that is, if your humbucker has adjustable poles. Typically, one of the coils will have screwheads on the polepieces. Adjusting the bass side polepieces (low E) will increase the bass, the middle polepieces will increase the mids, and the treble (high e) the highs. In reality, you aren't really adjusting the tone, but rather the output of the individual strings by adjusting the corresponding polepiece, ie, if you raise the low side polepieces up high, and the high side polepieces low, you will hear the bass strings more. The good thing is, it's all easily reversible...