Stylus motion modeled on a CAD program. When stylus is deflected sideways on an arm with an offset angle it 'scrubs' fore and aft along the groove, causing Frequency Modulation of the audio signal, typically excited at the mass/compliance resonance frequency. In this case, +/- 0.0586 inches sideways deflection causes 0.0079 inches backward 'scrub'. With no offset angle, the FM frequency is DOUBLE the resonance frequency. Counterintuitively, this doubling is actually a GOOD thing!