I have a Carvin LB20 4 string bass from the early 90's...neck through, and pretty sure the sides are Koa. I love to play this bass, but not crazy about the tone. Stock Carvin pickups in it, and have also tried EMG actives in it. But still don't like it. Searching for a fatter, more round tone. Any ideas on pickups that might suit that need? Thanks!