Alex Kenis put to the test the hypothesis that since guitar pickups with blade polepieces present a more or less horizontally uniform magnetic field, horizontal (side to side) string movement should not be picked up very much.

This has implications for timbre, because the horizontal component from pickups that have individual pole pieces is a distortion. The fundamental (first harmonic) translates to a double frequency signal, due to the string approaching the pole piece twice per cycle.