How do you get sound from a big panel?  By DrM (MUGfounder & ex-MUGmaster). BS, MS, AA, AS, BFD.  Ahem

First off, you need a magnetic field.  Magnetic fields cannot simply exist by themselves, they have to start somewhere and end up elsewhere (unlike electric fields which just start somewhere and can just disappear off to infinity).  This assumes no magnetic monopoles which have never been experimentally discovered.  Here’s a North South bar magnet.

All the lines go between North and South.

How close together the “lines” are (there really aren’t any lines, it’s just a continuous field, think of it like a topographic map) show how strong the field is.  If you want to control the shape, and strength of the field just move the N and S poles around.

Here you see a strong, linear field between the two poles.

Finally, as we all know alike poles repel each other, here’s a picture of how that works.

Now we have the basics of magnetic fields, next how you can use them.