Back in the early 70s, Bill Bartolini started developing upgrade pickups for professional musicians. With the new popularity of Jazz basses, their limitations for use in the studio made many professional bass players come to Bartolini for help. As a physicist and acoustic guitar luthier, he leveraged his deep knowledge of acoustics to create pickups that produce the most natural, musical voice from the instrument. He added shielding to block radio signals and noise. He developed a method of sealing, isolating, and stabilizing the coils so they could be encapsulated in epoxy to eliminate microphonics the nasty noise you get when you touch typical pickups.