It's pretty clear to me, after a lot of expermenting with it, that the magnet and coil wave intermesh like this:
Peak voltage occurs when the center of the magnet and center of the coil are in alignment.
The wave changes polarity when the NSNS magnets pass the coils. With NNNN, you still get the wave, it simply doesn't change polarity. With NSNS you get as much as twice the pulse rate, hence additional voltage.
If you have two coils and one magnet, you will get a long 0 voltage line between widely spaced pulses, just as finsawyer predicts.
If you have two magnets equally spaced NS energizing two coils connected in series equally space, the voltage will simply be cancelled out.
