What do guitar pickups pick up?

Tim Wescott · 2016-06-02T15:19:17+00:00

Looking at my kid's bass, the pickups have two pole pieces for each string. Looking at pictures of 6-strings, the pickups have one pole piece for each string. As best as I can figure, the bass pickups are sensing motion that's parallel to the body of the guitar, while the 6-string pickups are sensing motion toward and away. Yes? No? I'm totally cracked? I went looking for a good resource on the theory of just how pickups work and there seems to be one explanation that's been copied around a jillion times, more or less to the effect that the motion of the strings disturb the magnetic field and induce current in the coils. Well, duh, yes, can we move this out of freshman highschool physics and at least into freshman _college_ physics? I know at least one of you out there has actually wound pickups -- can you point me at any _good_ theory texts? I get that the pickup-string system is a variable reluctance machine, and that the pickups are magnetically biased. Beyond that I have theories, but I'd like to have a resource where someone _else_ has cranked through the math for me. TIA. (Knowing why folks seem to want to use Alnico rather than rare-earth or good ceramic magnets would be good, too, but that's not as important to me at this juncture). -- Tim Wescott Control systems, embedded software and circuit design I'm looking for work! See my website if you're interested