HI, I've got a bass with the Bartolini soapbar pickups and NTCTH preamp (two vol knobs, bass, treble and mid boost/cut). The bass frequently needs a push in the 600-700Hz range and the high frequency adjustment on this bass is too high in my opinion. The low end is a tad boomy, too, and could be improved by optimizing the eq. Is it possible to adjust the frequencies that are boosted/cut, or can I put a sweepable mids option on this setup? If so, what skills does this mod require? Thanks for the help.