I sold one of my basses to a co-worker (a Steinberger Spirit), and I went over to his place today to help him change strings and give it a quick setup. He bought new Labella .105 double-ball roundwounds. The bass still had the factory roundwounds installed and played well with no buzzes. I went through and set the relief to .014 to start (a minimal change) and the string height to 3/32". I slowly increased the height until it played well fingerstyle, even with enthusiastic playing. However, as soon as he switched to pick, everything fell apart. Buzz city! I kept increasing string height, no luck. I also added a little more relief - no soap. At this point, the bass is set up like Jamerson's. The buzz is up and down the neck, mostly on the E but also on the A. One thing I'm noticing is that the neck end ball windings are long enough that they're actually riding on the zero fret. However, I can't see how that could cause a buzz. Looking at the clearance between the string and other frets when a note is fretted, we can't see where a buzz would be coming from. All hardware is tight. It doesn't sound like trussrod rattle. Our next step is to remount the old strings, readjust and see what happens. Could it be the strings?