Yea , the old one will be a backup in case I really need it . Part of the problem is it just doesn ' t seem to be pushing through the same kind of power it used to . I think it ' s just getting old and tired , though maybe I need to do some really deep cleaning <| sep |> Moving electrons create a magnetic field , in a circle around the direction they ' re moving . If you make a coil of wire and send electrons through it you create a fairly uniform magnetic field inside it . If this coil is put near a permanent magnet it will be attracted or repulsed , depending on the direction of the field . If you reverse the directions of the electrons you reverse the direction of the field . If you do this rapidly attached to a membrane or the like it vibrates the air fast enough to be heard as sound .