Here's my issue....just received a custom bass with my choice of pickups (Bartolini 59J1's mated to an Audere pre). The bass kills when I'm playing fingerstyle by when slapping, it totally disappears in the mix. Just totally thins out. No booty at all! No issues with any of my other basses (Lakland 55-01 w/stock pups and US Fender Jazz w/Bart Classic Series Single Coil Brights). I am a fan of Barts but I don't know about these particular pickups. Any info provided would be greatly appreciated. Any recommendations?