Ok so my passive MTD Beast 4 sounds awesome as-is, being passive with the exposed pole piece Bart j pickups. In certain songs and compared to some of my other basses it can sound slightly thin? I also have to boost the gain and master more so than others. So what are some suggestions to beef it up a bit still remaining passive? I thought about replacing the Barts with another set of passives but don't have a lot of experience replacing pickups. EMGs? Another Bart set? Outboard preamp? Thanks!